Tuesday, December 6, 2016

Today i am hear to write about submersible pump control box wiring diagram , in this post you will complete understood about 3 wire submersible pump wiring diagram which is an single phase submersible pump motor. Why we called a single phase submersible motor a 3 wire submersible, that we also know that we have two wire in single phase power supply.
As you know that we have two types of winding in a single phase motor and these coils have also two starting and finishing ends, So we connect one one end of each coils and make a common point which know also with name of common point. And the other ends called starting and running terminals or connection. So we have 3 wire terminals or wire which out form the motor , that's why we called this 3 wire motor.
In the post you will completely learn about single phase submersible pump control box wiring diagram, and this diagram not to hard to understand like there own diagram which is mostly available in control box back side.

Single phase submersible pump control box wiring diagram - 3 wire submersible pump wiring diagram

In submersible pump control box we use a capacitor, a resit able thermal overload and DPST switch (double pole single throw). The wiring connection of submersible pump control box is very simple. Here is the complete guide step by step.

  • First of all switch of the main circuit breaker in your distribution board, this for that reason that you can work safely and protect himself form electric accidents.
  • Then connect the supply to input wire connectors. 
Now if the box is not wire then flow the steps and if the box is wired then last steps is for you.

  • After that get connection from wire connectors and then connect your neutral and Line wire (hot wire / phase) to the double pole single throw switch as i shown in the below diagram.
  • Then get hot wire connection form DPST switch and connect to the reset able thermal overload protector. And form overload protector connect this (black wire) to one of the output wire connector.
  • Now get your neutral wire (blue) form the switch and connect to capacitor, and form same terminal of capacitor connect it to one of the output connector.
  • Then connect a wire form other free side of capacitor terminal and connect to the one of the out wire connectors which i shown with red or brown color in diagram.
  • In 1 number connector connect your ground or earth wire as i shown in diagram with green color.

Now you have 4 out put wire connector, in which 1 number for earth connection, 2 number for starting terminals because this wire comes form capacitor, 3 number for running wire for motor and 4 number for common.
So you need to connect the running, starting and common wire of submersible pump to control box, so mostly in submersible pump 3 wires the Black color wire is common, Blue is Running and Brown or red for starting, But these color can be change or may be in your submersible pump different color wire are used. 

First if you know about the starting, running and common wire then connect it box connector as i shown in the below single phase 3 wire submersible pump box wiring diagram.

submersible pump control box wiring diagram
single phase submersible pump starter wiring diagram

Now if you did not know about the star, run and common wire in your pump motor then follow the below compressor terminals identifying tutorial and same follow the steps to find out identify submersible pump wires start,run and common. (Note that identify compressor terminals and submersible wire method is same)

Also read
How to identify start , run and common in single phase motor or compressor?
How to control a single phase motor using circuit breaker?
How to wire resetable overload?
How to control and wire a single phase motor with contactor?

In the above wiring diagram i shown the complete method of submersible pump control box wiring and installation diagram. Now if you have any question regarding single phase submersible pump starter wiring diagram then you can use below comment section.

Wednesday, November 30, 2016

As you know that i also published a post about wiring water heater, today i am writing about testing water heater element. As you know that we use water heater element for heating water. The testing of water heater element using multi meter or ohm meter is too simple connection. So lets start step by step it. As you know that electric water heater we use two or one element for heating water. If two element and water heater stop producing the heating then you can test or check your upper or down water element by using this method which i am gonna to to share with you in this post

Testing Water Heater Element Using Multimeter or Ohm Meter

Before i am telling you about the process of testing, first we get step one which protection. So first switch of the circuit breaker form your main distribution board which you used for water heater or if you don't know which breaker is control the wiring connection of water heater then switch off the main circuit breaker and then start work.

Now remove the water heater element form the water heater thermostat and then set your multi meter knob on connectivity testing. Or set your multimeter on ohm testing or diodes testing. Then connect your testing leads to water heater element terminals or connection points as is shown in the below diagram.

testing water heater element

So if the meter did not shown any reading like above diagram then it's means that water heater element is cut internally. However if it's shown reading like below testing water heater element diagram.

test water heater element

In the above diagram i shown that meter shown the resistance, so it's means that your element is working fine however if your water heater is a shortage problem then test the shortage as shown in the below method.

how to test a heating element with a multimeter

For testing shortage in your water heater element, you need to connect a multimeter one testing lead to connection terminal and other lead to element body as i shown in the above diagram. Note that if your multimeter shown the reading or connectivity as i shown in the diagram then your heater element is internally shortage and you must change it. However if it don't show any reading then your element have no shortage problem and you can use it.....

Also read
How to wire water heater?

Message :
I think after this post you will be no need more help for testing water heater element using multi meter or ohm meter. However if you have any question or any suggestion then you can use the below commenting system.

Monday, November 21, 2016

Today i am gonna to to guide you about how to fix refrigerator compressor not running problems, which we mostly face. This is a complete  guide of fixing fridge compressor not working or running problems. In this post i am writing about the common problems of refrigerator compressor and how to fix these compressor problems step by step with complete explanation.

Refrigerator Compressor Not Running Problems and How to Fix it

There are many problem which may case of Ref or fridge compressor stop working, but i try my best to cover some most common reason. We will highlight it step by step....

refrigerator compressor not running

Mostly compressor or fridge not working in case of no incoming power supply, for this issue first of all check your main distribution board to check breaker from which you get your supply for your refrigerator or for electrical outlet which is in used for your REF. If the breaker is in off or tip state then on it and if still it is trip again then check your supply line, may be a short circuit in your supply. Now if you switch on the breaker and breaker not tripping then check the outlet where your plug in the fridge plug, for testing the outlet (socket) the easiest method is that to plug in the plug of other electrical appliances (i.e example stand fan, set the knob of multi meter for testing AC voltage and insert the meter testing leads to the outlet.) Now if outlet have not receiving the power supply then change the outlet or fix the outlet problem. For that call a professional and if you can do this him self then do it but carefully. Here some posts which help you about outlets connection.

Also read
How to wire Electrical Outlets?
How to identify compressor terminals?
8 Reason of refrigerator / fridge not cooling
What is PTC Relay and How it's works?
What is working of Overload Protector?
How to check compressor winding?

Then next common problem of compressor not starting is that " your fridge supply wire will be cut internally", in this case your refrigerator all machinery will not work, the cooling fan, light etc. Note that in above electrical supply problem the refrigerator will same problem and other devices cooling fan , light etc will not working too.

The other common reason of compressor not running is that your fan internally light will be glowing but your compressor will not working, for that i suggest you test first of all the internally thermostat that refrigerator thermostat is working or not working, As you know that thermostat is connected in series with compressor and supply goes through the thermostat, now if thermostat is stop working and making a open connection then how can the electrical supply will run to compressor. For that fix the refrigerator thermostat or change it.

In some cases, some one or mostly children move the thermostat knob on switching off direction, so first of all chick the thermostat switch and if this on off direction then change the direction of thermostat knob. One thing more that we use thermostat switch for regulating the temperature and if your compressor start only for some time and before to make ice , compressor is switch off, so in this case your refrigerator thermostat switch is on low cooling , for that do setting of your refrigerator thermostat for high cooling.

Some time overload burn or cut due to high current flow, this happened when the supply off and again ON in some seconds, and the ptc relay can no start compressor again and compressor get high current and overload cut internally. (This happened because when compressor is running form the ptc internal heating resistor heated and make high level resistor shape between the run and starting terminal. As you know that ptc relay heating resistor provide a starting current form run terminal to start terminal for a small time and when it's provide current to start terminal it's heat up and due heat up the heating Resistor make high resistance and stop the current from run to start.)
So test thermal overload protector by using the multi meter and if thermal overload have connectivity between two points then your thermal overload is working and have no internal problem but if the thermal overload is internally open then change it. (Note that when thermal overload temperature is high it's make an open circuit, so the best method is to cool the thermal overload protector and when it's cool test it by using the multi meter.
PTC Relay is the main part which start the fridge compressor, When ptc relay stop working the compressor also stop running. So if your PTC (positive temperature coefficient thermistor) relay is not working or burn then change with same type of relay.

Capacitor is also one of the reason of  refrigerator compressor not running. Some time we use capacitor with capacitor start relay which make a strong starting current for starting compressor. There are two types of capacitor which we use with refrigerator compressor with relay which are starting capacitor and running capacitor. And if capacitor not working then change capacitor with same type of capacitor.

Due To Low Voltage
Voltage is also one of reason of  which make refrigerator compressor not running, so use a voltage regulator or voltage steplizer to provide the same ratio voltage which compressor need to start.

I hope this article help you fix refrigerator compressor not running problems, however if you have still face any fridge compressor not running or working problem then you can ask in below comments section.

Wednesday, November 9, 2016

Today i am writing about electric water heater wiring . I am writing about this post because in winter session we use hot and cool both water in our washroom and for other things. For heating water we use geyser and in which we use electric heater elements which heat the water. We use different type of electric heater element regarding voltage and regarding element type. We use water heater thermostat for controlling the water temperature. These thermostat we used for controlling the water heater element.
In this post i am gonna to share with some diagrams which clear your concept about the wiring of water heater geyser.

Electric Water Heater Wiring With Diagrams Explanation

In this post i am gonna to show some diagram form which you can learn how to wire water heater or you will be able to do the connection of water heater thermostat and element. Here i a shown a electric water heater geyser, in which two heater element instill  upper and lower. And also shown two thermostat switches but the upper thermostat switch is different from the lower element thermostat.

Both elements never on in same time and when the upper element is on working and when this element complete hotness it's range which is set up in thermostat. And when upper element work done the upper thermostat switch off the upper element and start supply to lower thermostat and through the lower thermostat the current will flow to lower element. This is called non simultaneous operation. Here i design the image diagram in which i shown the incoming supply neutral and phase which is connected thermostat and form upper thermostat the connection goes to the lower thermostat and water heater element.

electric water heater wiring diagram

Double Element Water Heater Wiring Diagram

Here i want to share with you electric water heater wiring symbol diagram, water heater wiring diagram which will help you in understanding. In the below diagram the upper element is ON and Lower heater element is OFF.

electric water heater wiring

When upper water heater element done his work, upper thermostat switch of the neutral wire to upper thermostat and provide the neutral wire to lower thermostat. As i shown in the below electric water heater wiring diagram.

water heater wiring diagram

In the above diagram i shown that the upper water heater element is switched OFF and lower heater element is switch ON.  Note that these element is 220 volts ratings and you can also 440 volts heater elements but you need to provide the line supply, my mean to lines or two hot wires supply 440 volts.

Single Element Water Heater Diagrams

Now Here i design another diagram for single heater element water geyser, in which i shown only one element wiring. On thing more the below water heater thermostat is different then double element thermostat.

water heater element wiring diagram

In electric water heater we use a type of element which have fix with thermostat switch. These elements mostly use in my country Pakistan. And these is instill in the bottom of water geyser. We called this type of water geyser a simple type of geyser. In this types of geyser one heater element in instilled with thermostat. The thermostat switch have two connection point just lick a bulb socket or holder. You need to connect the power supply neutral and phase to thermostat terminals. You can regulate the temperate form the thermostat switch, i shown the diagram of this types water heater element.

water heater element wiring diagram

How to Control Water Heater ?

The best option to to control the water heater form the circuit breaker box, so if you did not want to control the water heater form the main distribution board (DB Box) then instill a double pole MCB circuit breaker with water heater geyser. So i suggest to read the below posts.

How to wire and control electric machine form double pole breaker?
How to wire distribution board?

Message :

I hope you learn, how to wire water heater element with thermostat. Now i hope you understand the electric water heater wiring and it's water heater wiring diagram.

Friday, November 4, 2016

In this post i am gonna to share with you a room wiring diagram in which i shown the complete electrical wiring instillation. This a simple and basic guide and in this room electrical wiring diagram i shown a electric board which consist  two electrical outlets, 3 switches and one dimmer switch. The distribution supply comes to board and from the board it's connected to the bulb sockets and ceiling fan. I also shown the the power socket outlet / 3 pin socket wiring for which i get another connection from DB board which will be used for electrical heavy loads.

How To Wire  A Room / Room Wiring Diagram

The below room wiring is too simple connection example, fist i want to show you the room electrical wiring diagram and after that i will explain you ever part of diagram.

how to wire a room
Room electrical Wiring Diagram

In the above room electrical wiring diagram i shown a electric board in which i shown two outlets 3 one way switches and one dimmer switch. Note that this a simple wiring instillation diagram for one room in which i shown the wiring connection of two light bulbs and one ceiling fan connection. I also shown the wiring connection of 3 pin socket / power outlet. For complete understanding the below wiring room follow the below steps.

  • First of all switch of the main circuit breaker in distribution board and then start work.
  • Get the neutral and phase wire for room connection from distribution board.
  • Then connect the neutral wire to outlets, to bulbs and ceiling fan as i shown in the above diagram. (in the above diagram i denoted the neutral with "N" and with black color).
  • Then connect your phase (hot wire/ red color wire) to the switches and to outlets as i shown in the above diagram.
  • Then provide the hot wire form switch to bulb and form 2nd switch to bulb 2. Then connect the hot wire form a one way switch to dimmer speed controller switch and then from dimmer switch connect the hot wire to ceiling fan as i shown in the above diagram.
  • If the board base body is made form metal then connect the earth (green wire) to board body base.
  • Do the power outlet / 3 pin socket connection as i shown in the above room wiring diagram but get this supply from distribution board.
  • When you done it make sure that you done all connection correct.
  • Now switch one the main circuit form DB board.
However after doing wiring in home or room we follow some testing methods, IN SHA ALLAH soon i will write about this. Now i hope you learn about the room wiring diagram and now if you will be able to wire a room in House wiring.

Wednesday, November 2, 2016

In this post you will learn about checking compressor windings or testing compressor windings. As you that in refrigerator or fridge compressor we have a electric induction motor which rotate the pump. In fridge compressor mostly in rated in single phase which have 3 terminals. i already publish a post about the start, run and common identification guide on this blog.
Some time when our refrigerator compressor stop working or not running problem then we must called a professional to test compressor or refrigerator. But if you want to check your compressor him self then this post is for you.

In this post i am telling you about some main and common reason of compressor not working and about testing compressor methods. There are many problems which we face in electrical refrigeration system and due which or refrigerator or Air conditioner stop working. But this post specially about the check compressor motor winding.

checking compressor windings

Checking Compressor Windings Using Multi Meter

As you know that in single phase fridge or air conditioner compressor we have internally instill a single phase motor which consist two types of winding which we called main winding (ruining winding) and Auxiliary winding (starting winding). But if the compressor have receiving the power supply and still not working or running then may be it's starting capacitor or relay is not working. But if you want to test compressor winding then follow the below steps.
First of all i want to gave an example of fridge compressor

If you want to check your fridge compressor then flow the below steps.

  • First of all plug out the fridge main electric plug. or switch of the supply which is connected to the fridge. 
  • Then see the relay and find our that which one terminal is common, start and run. The common terminal will be connect to overload protector or connect direct to electric supply wire. (note that direct wire was connected in those single phase compressor, in which the overload protector is instill internally).

  • After that find out the run terminal, in ptc relay the 2nd supply wire will connect direct to the run terminals of compressor, my means that the the 2nd wire which connect to relay point and that point supply goes to direct a terminal of compressor will be your run terminal.

  • Now you find out the common and run terminal of fridge compressor. So the other wire will be start terminal, otherwise 2nd supply wire will be connect to start terminal through a capacitor or heating resistor. (note that heating resistor is instill internally in ptc rely).

  • Now you find and marked your compressor terminal. Now set your multi meter knob on connectivity text or Ohm. Now connect one lead of meter to compressor common and other connect compressor un insulated body place. Continue this process with start and run terminal.

  • Now if you find our the connectivity of winding and body then it's means that your compressor winding is short with compressor body or winding is uninsulated with iron core. And if have not connectivity between terminals and body. Then flow the next step.

  • The next step to test it's resistance between one another. Test the compressor by unsung below method . So first read the below post, and flow the method to test the compressor.

How to identify compressor terminals?

  • Now if your compressor terminals reading shown same as in the above post then your compressor winding is not burn or if it's shown different reading between common, start and run then your compressor winding is burn.

  • Now if compressor winding resistance shown same as i shown in the identifying compressor example then change your PTC (positive temperature coefficient thermistor) relay and com.. overload protector or capacitor and if still not working then call a professional.

Mostly in some compressor in which the common terminal is on upper side then left side will be start and right hand side will run terminal, and danfoss compressors in which the common terminal on down side the right side will be start terminal and left side will be run as i shown in the below diagram.

compressor terminals diagram

How To Test or Check Air Conditioner Compressor Motor Windings
  • Now if you want to check the Air conditioner compressor then it's also too simple, in air conditioner compressor we have label in which the R , S and C written or parked.

However if this rubber label is not available or removed then follow the below steps.

  • First of all, terminal of air conditioner compressor terminal is connect to overload protector or direct to supply wire is your common terminal. Mostly we use white or black color for common. The other supply wire will be connect to capacitor and to compressor terminal will be your run terminal, mostly in split unit AC the blue color wire is use for run terminal. And the other wire will be your start terminal which will be connect to capacitor. Mostly this red color wire used for start terminal connection.

  • Now set the multi meter on ohm or resistance tasting or use a ohm meter and check the compressor, follow the same method as we use for fridge compressor terminal. However lets see the example.

  • If your resistance between common and ruining is lower then resistance between common and starting then all is right and your compressor is winding is good condition and if that shown different result then compressor winding is burn or cross.

If it's shown good result then flow the steps.

  • Now test the compressor shortage between compr.... terminals with compressor body like fridge compressor and if the meter shown no reading then compressor winding is not shortage with body and if it's shown the reading then it's means that compressor windings is shortage with compressor body.

  • Now if you check compressor motor windings and not find any problem and still compressor did not run then change the capacitor and if still compressor not working then check the overload protector.

As you know that overload protector is connect to main terminal of compressor in series and if compressor overload protector stop working or internally open, the compressor is also stop working. However these are simple methods for checking compressor windings of single phase and now if you have any question then you can use the below comments section.

Friday, October 28, 2016

As you know that Safety is important in electricity works. Today i am writing about shunt trip breaker wiring diagram which related with safety and protection of electricity. As you know that electricity is dangerous but it's become more dangerous when it's upgrade from the 220 volts to 3 phase 440 volts. As you that mostly we use 3 phase  system in industrial state where we can not protect our electrical distribution using RCD (residual current device).
In Single phase wiring or house wiring we use electric power supply between phase and neutral which can be control by using a simple double pole RCD Breaker. But When it's come to high load places or where we use the three phase supply then use a MCCB (module case circuit breaker) Shunt trip circuit breaker with emergency push button switch which we know better with name of EPO (emergency power off) button.

Shunt Trip Breaker Wiring Diagram with EPO Button.

In this post i am just tell you about wiring of single EPO button with shunt trip MCCB breaker. In industrial state,  Electric operator duty is to operate the machinery and his duty is on the front of Main panel board.
Now if a short circuit is done in electrical instillation or other electrical accident, the operator can easily push a small push button switch and the all electric power supply will powered off. If we comparison it between switching off the main circuit breaker then it's will get more time.
In the advantages of shunt trip breaker, a most important things is that we can instill the emergency switch (EPO) anywhere, from where can easily push button or where the push button is near to us.

One thing more that we can instill more then one EPO buttons for one breaker and every button will work same. However is this post shunt trip breaker wiring diagram i shown only one EPO button and INSHALLAH in next post i will show you instillation of  multi EPO (emergency power off) buttons for a single shunt trip MCCB breaker.

Also read below
How to wire 3 or 4 pole MCCB Breakers?
How to wire RCD Breaker?
How earthing system works?

How Shunt Coil Work

In simple words, a shunt trip a electromagnetic coil which make magnetic field by providing external power source. In the coil a move able rod is fixed with spring and when we provide the supply
The shunt trip move able rod hit the tripping point or disconnecting point of circuit breaker internally and the breaker become off or trip.
In the MCCB circuit breaker, we have a push able button or place which is named with "push to trip" and when we switch on the breaker and push this button the breaker become switch off and trip due to pushing this button.
The shunt trip coil rod push this point internally when the shunt coil is operate.

Here is some images of shunt coils and after that we will discuss the shunt trip breaker wiring diagram with image + symbol diagram.

Shunt Trip Device

breaker shunt trip coil

shunt tripping device

Now lets how to wire shunt trip device (accessory), it's too simple as i shown in above shunt trip device images that a shunt coil have only to wires , just like a magnetic contactor or magnetic relay coil. But you must provide the power source regarding coil rated volts. You can find out the rate coil label on shunt coil, circuit breaker or on shunt trip coil.
But the question is that how to wire it. And the answer is that "it's also too simple".
We use a push button switch for shunt coil which we know with it's short name "EPO" which i discuss in my above words.
In EPO switch we have four terminals in which tow are Normally close with each other and other two are normally open.
So we need to provide the supply / current to the shunt trip device circuit breaker when the emergency moments come.

I.e example " if we have a shunt trip coil which is operate on 220 volts, so we need to provide the 220 volts AC current to shunt trip coil to operate or to do trip the breaker in emergency time. So our neutral will be connect direct to the shunt tripping coil and Phase (hot wire) will be connect to coil other side through the EPO push button switch normally open contacts.
So the EPO switch will be normally open and when we push the switch in emergency time the switch normally open contacts will make a close contacts connection and the hot wire current start flowing to the coil and complete the circuit because the neutral wire current is already connect to coil. So the coil will make a magnetic field and push the rod, the rod will press the trip point and breaker will disconnect the power supply to load.

Here is complete explanation of shunt trip circuit breaker wiring diagram which help you understanding completely.

shunt trip breaker wiring diagram

What is the purpose of a shunt trip circuit breaker

The main purpose of a shunt trip breaker is that we can easily switch off main circuit breaker form our nearest place in short time and can safe us from electrical accidents.

Final words
To wire a shunt tripping breaker follow the below steps.

  • First of all wire your Circuit breaker.
  • Then connect the neutral wire to shunt trip coil.
  • Then connect the Phase (hot wire) to the EPO button normally open contact.
  • Then get connection form EPO other side of normally open contact and connect to the shunt trip coil.
That's all you done it, in the above diagram, i shown the complete the of shunt trip circuit breaker wiring diagram using image and symbol diagram, however now if you have any question regarding the shunt trip breaker wiring diagram  with emp switch or want to gave us some suggestion then use the below comments section below.

Monday, October 17, 2016

As you known that capacitor are numbering in those electrical and electronics component which we use very much in different circuits for different uses. In this post i am just writing about that what capacitor and how it's works.

Capacitor Definition and Explanation

Capacitor (Cap) is a component which consists of conducting surface separated by by a non-conductive region or by a layer of on insulating me dim called dielectric. Note that the non-conductive region mean also dielectric.
or An example of dielectric is that it's a electrical insulator. I.E example is glass, air, paper, vacuum can be use as dialectic in capacitor.

The purpose of capacitor is that to store electrical energy by using electrostatics. capacitor can better explain by below definitions.

  • In simple words a Cap is an electronic component which can story the electrical energy from of electrostatic field is called Cap... or condenser. Note that we also called condenser to Cap...
  • A device which is consists with two metal plates, in which any insulating medium use between palates as dielectric is called cap....
  • If we place two conductor plates near with one another and place a insulating material between the plates and provide the electric charge to plates from potential difference source (voltage) source is called Capacitor.
  • Any two conductors in which electric flied can be maintained is a from of cap..
  • In  simple words a CAP is a electrical device which is consists two conductive plates in parallel and which is separated by an insulating material is called dielectric.
Also Read Below

In capacitor we have connecting leads which is connected to these parallel conductive plates. In the blow diagram i shown internal structure - construction of capacitor and it's circuit symbols.

capacitor structure and capacitor symbol diagram

In the above diagram i shown the Cap symbols which we use in circuit for Cap. If we have an paralleled plate type of CAP. So one plate supply wire is connected to positive end and other is to negative or earthed. When we connect link of this type of  Capacitor to the battery supply. So the electron flow start from plate A to plate B for a time. (It's happened because Plate A can bearer more charge due to plate B earthed)
Due the negative electron emission from plate A and Plus to B plate. Due this electron emission- the positive charge on plate A and negative charge on Plate B.

Monday, October 10, 2016

In house wiring, we install two types of wiring in which one 3 phase wiring installation for house and other one single phase installation. In this post you will learn how to install three phase electrical wiring using a simple diagram in which i shown how to install three phase 4 wire system in a multi story building. One thing more that i shown 3 distribution boards in which every story have there own electrical main distribution board.

3 Phase Wiring installation In Multi Story Building / House

The three phase 4 wire system installation in home is very simple but to understand you must study each part of this class and devices which i use in the below diagram. I start from this from step one.

Utility Pole 3 Phase 4 Wire System

In the diagram is start from the utility pole and i get service line supply from utility pole to 3 phase kWh energy meter. This utility pole connect to step down transformer (supply from sub station). My means that the pole supply comes from the substation or step down transformer.

3 Phase kWh Energy meter

I also shown the wiring diagram for there phase 4 wire system kWh (kilowatt-hours) meter, I also published a post about the wiring and installation of three phase four wire system kWh energy meter. So kindly read the below article if you did not understand the method of 3 phase kWh energy meter connection.

Also read
How to wire and install the 3 phase kWh energy meter?
How to wire Single phase kWh meter?

4 Pole MCCB Breaker

After the connection of energy meter, i connect the 3 Phase 4 wire power supply to the MCCB (module case circuit breaker). However if you can do this connection then read the below post.
Also read
How to wire 3 Pole or 4 Pole MCCB Breakers?

Now come to the connection for distribution board for one story. The method of installation 3 phase wiring is simple, you divide your load in three parts and each part have there own Line (phase). My means that divide your load in 3 parts and provide one one phase to each part.
Now here i have multi story building in which each story have there own single phase distribution board.
So we will provide one one phase or line to each story. And our neutral will be common but this will be common in circuit breaker output point and each story have there own neutral wire. So provide my Line 1 or phase 1 to the first distribution board and you can see in diagram. So come to Distribution board.

Distribution Board Wiring Connection

In the db board, i use the following electrical devices.

Double Pole MCB Circuit Breaker 63 Amps

I get phase and neutral wire from the main circuit breaker( 4 pole MCCB) and connect to double pole MCB (miniature circuit breaker). Note that double pole MCB will be consider a main circuit breaker for single phase distribution board for below diagram.

Also read below
How to wire double pole MCB breaker?
How to wire and install single , double , three and four pole MCB (miniature circuit breakers)?

RCD Brekaer.
I also install and wire double pole RCD (residual current device) in each distribution board. If you did not understand the wiring and installation of RCD then read the following post.

Distribution Electrical board Wiring for Single phase
How to wire and Install the double pole RCD breaker?
How to wire a 4 pole RCD circuit breaker?

Earthing or Ground connection

I also done the earthing connection in 3 phase wiring installation diagram in multi story house. I shown this connection by using a earth symbol and green wire. In the below diagram the earth symbol consider as earth electrode.

Also read
How earthing system works for protection?

AC Voltmeter Wiring connection for single phase

I also do the voltmeter wiring connection is each distribution board and you can see it in diagram. However here is some post which help you more then this. (Note that the VM denote the ACV voltmeter in below diagram.

Also read
How to wire a voltmeter for single phase?
How to wire a voltmeters for Three phase?
How to wire voltmeter selector switch for 3 phase with volt meter?
How to install the volt meter selector switch for 3 phase 4 wire system?
How to wire light indicator for 3 phase 4 wire system?

Ampere meter / Ammeter connection with CT (current transformer)

I also shown the ammeter connection with current transformer in 3 phase installation diagram for multi story house. The connection of CT is simple with ammeter but this will be better for you if you read the following articles.

How to wire a ammeter for AC and DC?
How to wire ammeter with current transformer?
How to do digital ampere meter connection with CT Coil?

Complete Explanation of Three - 3 phase wiring installation in a multi story building

The installation of three phase 4 wire system in multi story building is simple if you want to use single phase supply for each story. Note that by doing this type of connection you must wire 4 distribution board where one for main MCCB circuit breaker and other for each story. And you can also do these connection in a single main DB but you must use a big size  distribution board box where you can easily install all circuit breakers. But if use there own distribution board in every story then this will be better option.

So let's do it step by step.
In the 3 phase wiring diagram i shown a utility pole from where i get service line connection for 3 phase kWh meter (energy meter). Now i connect the supply wire Red, Yellow , Blue and Black to the energy meter input connection terminals and get supply from energy meter out going connection to load.
One thing more that that we use color code of red yellow and blue when we are doing the three phase wiring but when it's come to the 3 phase four wire system, we use the black for neutral. And when we are gonna to doing connection of single phase ( current between phase and neutral) then we use red for phase (hot wire) and black for neutral.

After the connections of three phase kWh meter we provide the 3 phase 4 wire supply to 4 pole MCCB circuit breaker which on th- 100 amp. Now the next step is outgoing supply from the 4 pole MC CB circuit breaker. The N neutral wire will be common for each story or load and you see it in the below diagram, that i connect the neutral black color wire from the breaker and wire it with a connection point connector.

So the neutral will be common for each story or distribution board and one one phase will be distribute to the each story. So i connect the neutral wire to a neutral connection point or connector from where we can get connection of neutral for load.
I connect a neutral wire to this neutral connection point and connect to the story 3 distribution board double pole MCB breaker. And then i get Phase wire from the MCCB and connect to this MCB breaker. Then MCB supply goes to the double pole RCD and you can see it in below diagram. Note these two breaker are 63 amps.

3 phase wiring installation diagram

Now from the RCD breaker the neutral wire goes to neutral connection point as i shown in above 3 phase wiring diagram and the phase (hot wire) red color is goes to all single pole MCB breakers which i shown in above diagram.
In the above3 phase wiring diagram the 2 single pole breaker are 16 amp , 2 are 10 amps and other sex are 6 ampere breaker. Note that this just in example and you must install or wire breaker regarding your total load. Note that use high quality wire for your wiring system. And always chose or use the wire regarding load (amps).

I also wire the voltmeter in above three / 3 phase wiring third story building wiring, for which i get hot wire connection from input points of single pole MCB breakers and neutral from neutral connection connector point. And same i wire the light indicator.
In the above diagram i shown the ammeter connection with current transformer (CT coil) and also provide the complete method of wiring and installation of ammeter with current transformer in above links. However use always the current transformer regarding the ammeter requirements. If the ammeter is 60/5 then use a current transformer with same value 60/5.
You can also use AC series type of ammeter but the CT type ammeter is better then ammeter which we use between supply in series connection.

As i shown in above 3 phase wiring diagram that i do the earthing connection, and provide the earth wire to each point. I shown in bottom of diagram earth symbol with name of earth electrode and from here i provide the ground connection to all story loads / rooms etc. And in each story i use the earth connection point, from where a person can provide the earth wire to any load / electrical machine, outlets etc.

In the above 3 phase wiring diagram 1,2,3,4..... in circle means that these wire goes to load 1 , load 2 and load 3. It's mean that if the 1 hot wire (phase - red) wire goes to the room A then the neutral 1 (black wire) is also for the room A and the earth connection 1 number wire is also for the same point (load- room A).

Follow the same method for story 1 and story 2, but provide the L2 (phase 2 - Hot wire 2 ) to the story 2 and Line 3 to story 1 which is bottom of 3 phase wiring diagram. However lets get another review on diagram step by step.

3 Phase Wiring Step By Step Guide Multi Story Building

  • First of all provide the serves line wire to the 3 phase kWh meter from utility pole.
  • Then provide the 3 phase 4 wire supply to 4 pole MC CB Circuit breaker.
  • Then connect the neutral point from MC CB to neutral connection point.
  • Then get connection from the main neutral point and connect to story 3 or other story double pole MCB circuit breaker.
  • The connect the L1 to the story three double pole MCB between the CT (current transformer) and from MCB connect neutral and phase to the RCD circuit breaker. (Note some people know RCD with name of ELCB  (earth leakage circuit breaker).
  • Then from RCD connect the neutral wire to neutral connection point and phase to circuit single pole breakers.
  • Then provide the supply to the voltmeter and indicator light.
  • Then Do connection between CT coil and ammeter.
  • Then provide the earth connection (green wire) to story three earthing connection point.
  • Then provide the supply to each loads from circuit breaker , neutral connection point and earth / ground connection connectors.
That's all , same follow this method for each story. but provide there own different phase wire and neutral wire.


This in example of 3 phase wiring installation in multi story building, and i use different ampere circuit breaker, just for your understanding. However always use breaker regarding your load. Now i hope you understood the 3 phase wiring in multi story house or building, now if want gave us suggestion or any question then use the below comments section. 

Saturday, September 24, 2016

In this post you will learn about the replacing capacitor in ceiling fan. Ceiling fan numbering in those electric appliances and machines which we use very much in our life and mostly in summer season. In AC fan we have two types of internally winding which called main winding and starting winding. Most people know main winding with the name of running winding and starting winding as auxiliary winding. However in this post we only high lights the procedure of replacing capacitor in fan.

Replacing Capacitor in Ceiling Fan Motor or other Fan Motor

When your fan running slow or not running and make a type of sound then maybe your fan winding problem or capacitor but mostly this problem comes with capacitor. I also publish a post about role of capacitor in fan and you can learn by using the below link.
Also read
Role of capacitor in fan
Ceiling fan capacitor connection diagram
How to control speed of fan using speed control switch
How to control speed and wire dimmer switch for ceiling fan

So we use capacitor with fan but when capacitor become week, our fan RPM or speed become slow or if the capacitor stop his duty totally or blown then our fan stop running. Note that in some case the fan slow due to the Dimmer switch which we use for ceiling fan to regulate the speed. So if your fan running slow then first chick your dimmer switch , may be some one regulate it on slow direction. However fallow the steps before you gonna to change your capacitor in fan.

  1. First of all switch off your supply from your main DP board
  2. Then open connection point of fan where the capacitor instilled from company
  3. Then check the capacitor value and buy the same value capacitor from market or online store.
  4. Now remove the old or blown capacitor wire one by one and connect these wire to new capacitor.
Note that change the same ratio capacitor to fan. If a fan have 2 uf capacitor then replace a 2 uf capacitor to fan.
After replacing capacitor fix all thing and start your supply form Distribution board and check the fan, if ceiling fan running slow or still fan is not starting change the dimmer switch and after that if fan have same problem. Then this may happen in case of following problem.

  • Your fan main winding or starting winding is burn if fan still make sound and not starting. Or the fan bearings is jam.
  • If the ceiling fan not staring and have no making sound or vibration then may be your fan internally winding is burn or cut ( open circuit).
  • OR your in coming supply is not receiving to the fan. 
Now If your fan not starting and have no sound then conform that the current supply is receiving to fan , so if fan receiving the current and still not working and not making any type of sound then may be your fan internally winding is cut (open circuit)/ burn. Or maybe it's connection wires are cut.

Now come to explain it using a simple clip art replacing capacitor in ceiling fan diagram. In this below diagram i shown the ceiling fan motor and it's connection point where the capacitor instilled. For example your fan capacitor is blown and you want to change it with new one, then the first option to check the number of old capacitor. It's for that reason that you buy a new capacitor with same model and ratio. Now if your fan capacitor have 3 wire red, yellow and purple. So if all wire are connect to fan other wires then buy same type of capacitor and if your fan old blown capacitor have three wire and only two is connect to the fan wiring then follow these step.

  • First of all buy the same type of capacitor form market.
  • And if the same type of capacitor is not available then check the capacitor value. You will find that there two types of value written on capacitor. For example 1.2 micro farad and 2.3 micro farad . You will see that the red and yellow wire capacitance value is 2.3 uF and red and purple wire value is 1.2 uF. So your common wire is red. I also shown the 3 wire capacitor diagram inside the below ceiling fan capacitor changing diagram
  • Now if the red and yellow is connect to the fan then buy a 2.3 uF capacitor form market and connect it to the fan.
The all process of replacing capacitor in ceiling fan i shown in the below diagram which help you in understanding.

replacing capacitor in ceiling fan

In the above replacing capacitor diagram i shown three wire capacitor, it's for that if you required a 2.3 uF capacitor and which is a two wire capacitor and in market the two wire capacitor is not available then buy a three wire capacitor which have a value of 2.3 micro farad. And connect the 2.3 uF wire to the fan a leave the other wire as i shown in the above diagram. Note that insulate the other wire.

Replacing 3 Wire Capacitor to Fan Motor In Speed Control Switch

If your fan motor is working on three wire capacitor and it's connected to the fan speed control switch then connect the connection as shown in the below diagram and also read the post which i given after below replacing 3 wire capacitor to fan diagram.
replacing capacitor in ceiling fan

By reading the below post link, you will completely understood about the replacing of 3 wire capacitor in fan and also read the other post for better understanding.
Also Read Below:
3 Wire ceiling fan capacitor instillation with speed controller switch
3 wire ceiling fan motor capacitor diagram
5 wire fan motor capacitor diagram and explanation

I hope now you will completely understood the replacing capacitor in ceiling fan motor or other fan, however if you have any question regarding this post then ask me comment section. 

Wednesday, September 21, 2016

In this  post i am gonna to tech you about ceiling fan speed control wiring diagram, from which you easily learn fan speed regulating speeds. In this post i am gonna to share speed controller diagram with low, med and high speed diagrams. On thing more i also shown in the below that how can we control the speed of fan motor using 3 wire ceiling fan capacitor. One thing more we can also use dimmer switch for regulating speed of ceiling fan. However in my last most i shown 5 wire ceiling fan capacitor diagram, in which i also shown a speed controller diagram using speed control switch diagram.

Ceiling Fan Speed Control Wiring Diagram

First of all i want to clear you that we can control the fan motor speed using 3 method in which we can do the ceiling fan motor speed control using two methods, while in stand fan motor we can also regulate the speed by doing the connections in axillary winding / starting winding. For ceiling fan speed controlling we use mostly two methods in which on is by using speed control using three or five wire capacitor. And other one is using a dimmer switch from which we can control the RPM (revolutions per minute) of ceiling fan or other fan motor.
So First we talk about ceiling fan speed wiring diagrams, which i designed 4 diagram in which i shown Off , low , med and high speed direction of fan motor speed switch controller. Here is the fan speed low, high and med speed direction diagram,

ceiling fan speed control diagram

So As you know that by using 3 wire capacitor, we can control the speed of motor using speed regulator switch. So in the the above diagram i shown the switch in 4 types of diagrams. So for example our fan capacitor is 3 wire capacitor red, yellow and purple. So yellow for 1.5 uF and purple for 2.5 uF. So here is an complete diagram in which is shown the ceiling fan motor main winding and auxiliary winding / starting winding with speed controller switch, capacitor and AC supply. In the below ceiling fan speed control switch diagram i shown the fan speed switch knob on off direction.
ceiling fan speed control wiring diagram

In the above ceiling fan speed control wiring diagram i shown the main winding / running winding and i connect run wire of motor to the speed control switch and you can see it in above diagram that connection of run wire of motor in switch L point and and 1 and 2 for capacitor. I connect Purple color wire of capacitor to 2 terminal of speed Controller which 2.5 micro farad and 1.5 uF to 1 point of speed which yellow wire of capacitor. And red is common wire of capacitor and i connect this wire to start point of fan.

On thing fore the phase (line) wire to 3 point of switch and neutral to common wire fan motor. So in the above diagram the switch contacts on L to 2 it's means that  the 3 wire current is not connect to fan and fan is off.
So lets see the low speed wiring diagram of fan.

ceiling fan speed control switch wiring diagram
So in the above diagram the fan speed regulating switch contacts on L, 3 and 1 side and the line current is start to run wire of fan and 1.5 uF and the fan on low speed. lets see the fan on med speed.
ceiling fan speed controlling diagram
Also Read
Ceiling fan capacitor connection diagram
3 wire ceiling fan capacitor diagram
5 wire ceiling fan capacitor diagram and installation
Role of Capacitor in fan and single phase motor

So in above diagram the speed switch contacts on L , 3 and 2.5 uF and fan on running or start on 2.5 micro farad Cap and on med speed. Now lets see the High speed of fan diagram.

fan motor speed control wiring diagram

So in the high speed direction of speed controller switch the all contacts are connect with one another, and both 1.5 uF and 2.5 uF are connect to the motor, it's means that 1.5 + 2.5 is 4 uF capacitor is connected to the fan motor. So high capacitance number of capacitor is connected to fan motor and fan motor run fast on high number of capacitor which 4 micro farad. One thing more that don't connect too high value capacitor which is out of fan motor range. For example if a motor required 4 uf capacitor and you connect a 10 micro farad capacitor then the result will be bad and fan motor winding will be burn.

Fan controlling Speed Using Dimmer Switch

This is another method of controlling speed of ceiling fan, in which we use a dimmer switch from controlling or regulating speed. For better understanding about wiring connection of dimmer switch read the below posts.
How to wire dimmer switch for ceiling fan?
Fan motor dimmer switch diagram

(Note that this an Basic guide of single phase AC (alternating current) fan speed regulating)
I hope now you understood the ceiling fan speed control wiring diagram or ceiling fan motor speed controlling switch diagram. Now if you have any question regarding this post then you can use comments section.

Monday, September 19, 2016

In this post i am writing about the 5 wire ceiling fan capacitor wiring diagram, in my last post i written about the 3 wire capacitor diagram which we use for fan and can regulate speed by using speed controlling switch. Now in this you will learn about ceiling fan 5 wire capacitor and it's diagram.

5 Wire Ceiling Fan Capacitor Wiring Diagram

In ceiling fan we use the 5 wire capacitor for speeds, low Med and High speed. On this type of capacitor we have five wire in which two is common and 3 other for different value capacitance micro farad.
In the below diagram i shown a 5 wire fan motor capacitor with it;s capacitor diagram.

5 wire ceiling fan capacitor wiring diagram

In the above diagram i shown an image of fan motor capacitor which CBB61 and it's a 5 wire capacitor, the two gray wire are common and red is 4.5 uF 250V and Brown is 6 uF 250 Volts and Purple is 5 micro farad and 250 V.

Ceiling Fan 5 wire Capacitor Working and instillation Diagram for Fan regulating Speed Low, Med, High

Also read
3 wire ceiling fan capacitor wiring connection diagram
Ceiling fan capacitor wiring diagram
Role of capacitor in ceiling fan or single phase motor

Mostly we use this type of capacitor for speeds, as i told in my above words, so here is an diagram form which you can get idea of using this capacitor. in the below diagram i shown how can we regulate fan speed. Here i shown a diagram in which i shown a ceiling fan main winding / running winding and auxiliary / starting winding with capacitor with speed controller / selector switch and one way switch with low , med and high speed.
5 wire ceiling fan capacitor wiring diagram with fan speed controller
In the above diagram i shown AC supply and i connect the neutral wire to motor winding (common winding point) and the phase (Hot wire) connect to the one way switch and form switch connect to the motor main winding and capacitor all wires of capacitance which is 4.5 uF, 4 uF and 6 micro farad. and you can see that speed selector switch on low direction and when it;s switch move on the 5 uF," the ceiling fan will be on med speed and on 6 micro farad the speed will be high. This is an basic diagram of 5 wire ceiling fan capacitor wiring diagram and it's working.
Now if you have an question regarding this post ceiling fan wiring diagram 5 wire capacitor then you can tell me in below comments section.

Sunday, September 18, 2016

As you know we use single phase types motor in ceiling fan and a ceiling fan required capacitor to run. In ceiling an we use capacitor, in which one type capacitor have 3 wire. In this post i am gonna to explain the ceiling fan 3 wire capacitor wiring diagram. This capacitor have 3 wires in which one is common for both and other two for different value capacitance. My means that there are two capacitor instill in this capacitor and both value is different from one another.

Ceiling Fan 3 Wire Capacitor Wiring Diagram

The 3 wire fan capacitor diagram mostly available on capacitor but most people did not understood. And he always try to buy a 2 wire fan capacitor. But the 3 wire capacitor is better than 2 wire because we can use if for two different requirements.
In this capacitor one wire is common and between common wire and 2nd wire the capacitor is different then between common and 3rd wire.
One thing more in some ceiling fans we use this type of capacitor for regulating speeds. I.e example that form example when the fan motor start on 1.5 uf the motor will be on low speed and when the capacitor on 2.5 then the motor will be on med speed and when ceiling fan motor run on both capacitor in same time (1.5 + 2.5 = 4 uf) then the motor on high speed.  And as i told in my above words that we can use it for a fan motor which only required the 1.5 micro farad capacitor.
However ceiling fan 3 wire capacitor we use in fan for mostly for speeds. In fan we use speed regulator switch form which we can regulate the speed using capacitor.
We have 3 wire is ceiling fan capacitor in which red is common and other two are for different capacitors values.

Also read
How to connect capacitor to fan ( ceiling fan capacitor wiring diagram)?
What is role of capacitor in fan?

First i am gonna to explain the 3 wire capacitor diagram and you can easily learn form below three wire capacitor diagram.
ceiling fan 3 wire capacitor wiring diagram

As i shown in the above ceiling an 3 wire capacitor diagram that red is common wire and yellow for 1.5 microfarad and Purple for 2.5 farad. However IN SHA ALLAH in further post i will explain the fan 5 wire capacitor, regulating speed switch diagram and replacement of fan capacitor in fan motor.
Now i hope you understood about the ceiling fan 3 wire capacitor wiring diagram. Now if you have any question or suggestion then post on comments box below.

Thursday, September 1, 2016

As you know that there are different types of circuit breaker , in those circuit breaker a well known name is mccb which molded case circuit breaker and in this post you will learn about the mccb wiring and initiation. in this post i am gonna to share with you two diagram of mccb in which one is about the wiring of 3 pole mccb circuit breaker and other one is about 4 pole circuit breaker.
By using the the three pole circuit breaker we can control three phase power system and by using the four pole we can control 3 phase 4 wiring system. However i also share diagram about the wiring and instillation of MCB (miniature CB) and you can also read about those diagram and post by using the following links.

Also read below
How to wire 4 pole mcb
how to wire 3 pole mcb
how to wire a distribution board
How to instill mcb breakers in home wiring

How to wire Three Pole and 4 Pole MCCB circuit breakers

The wiring of mccb and mcb circuit breaker is same, and it's too simple but the difference between in mcb (miniature CB) and mccb is that we can use mcb the load between 0.5 to 100 amps and range of ampere of mccb is 1000 amps.
So if are doing a connection for distribution board which ampere is over then 100 ampere then we can not use the mcb and we must instill the MCCB.
The three pole type of molded case circuit breaker are use mostly for controlling the three phase system and this also design for that work. However we can use it for any work regarding work. If our single phase load is over than 100 ampere than we can also use this circuit breaker.
In the below mccb wiring diagram i show the complete method of wiring and installation of three pole molded case circuit breaker.

mccb wiring diagram

When we have to control a 3 phase circuit by using a breaker the first option to chose a three pole but if the circuit is three phase 4 wire system then this work can not be done with out a 4 pole circuit breaker. In the below 4 pole mccb control wiring diagram i shown the complete method of instillation and wiring of 4 pole molded case CB.

4 pole mccb wiring diagram

On thing more that if you are gonna to wire a multi storey building and instillation  three phase 4 wire system then use mccb in your main distribution board but chose your breaker regarding your total load. However further soon i will will publish post about wiring instillation in multi storey building diagrams and a guide in which i will also do the mccb wiring connection.

Monday, August 29, 2016

In electrical technology and electrical maintenance work, the most important thing is protection and safety and earthing is one of them. In this post is about what is earthing system or grounding. As you know that In single phase and three phase wiring we have a wire which is green or green plus Yalow and which connection is with electrical machine body which is called earthing but why this is important and how it's work. To clear these question from minds i am writing this post.
As i told in my above words that protection and safety is important in every work and when we talk about those works which is related with electricity power, the dangerous is very big then other works. Every one now that electricity is danger and but in world if some thing is dangers and make problem but every one agree with this that every problem have a salutation. In electrical works we can not say 100 % that we can make people completely safe from electrical shocks and accidents. But if we follow some protection roles and also do work with complete safety roles then we can stop these accidents  more then before.

What is Earthing System or What is Grounding System

Most electrical appliances, machines and motors body are made from the steel, these bodies are insulated to make safe but a Small mistake can case of big accidents. Due to this we face accidents in which many lost lives and money. The necessary is that to protect and safe him self from these accidents or do the right work which can stop these accidents. For that we do connection between electric machine steel body and earth by using a thick wire which is called earthing system.
Or we can said that the connection between electric appliances steel body and earth is called earthing system.o

In this process a steel or copper plate is buried in earth which we known with name of earthing plate and cooper wire is connected to the earthing plate. This wire connect to electrical machine body or frame to make a connection between machine body and earth. This is called earthing system or grounding system.

Import acne Of Earth / Grounding System in our lives 

All electrical machine or appliances insulated but if this insulation remove or hot or phase wire connect the machine body frame then some quantity of current live his right way and start flowing to the machine steel body which is called leakage current. In this case the workers which working on these machine can fell or get a big electric shock which may case of injuries or deaths.
But if we make a link between electric machines body and earth then the electric current flow through the machine steel body to earth and the human life safe from electric shock. In this process the electric current flow to earth instead human body because the resistance of earth is low contest a human body. The electric current flow always select way in which have a low resistance. And we can safe him self from a Strong electric shock.

How earthing system is working for protection of electric shock

In earthing connection we make a link between electric machinery by electric wire (which we called earth wire) with earth. The connection of earthing is that we  connect the earth connection wire to the metal body of electric machine which we connect which connect to earth. The connection of earth and machine by using the a conductor or electric wire is called grounding or earthing.
As you know that electron flow is called current and current always chose those way for flow which have low resistance.

So what happen when we did not do the ground connection to electric machine. When we did not do this connection and in case machine have faulty or the phase (line wire) connect to the machine body or the the machine is internally short circuit. So the phase current always try to flow to ground and when some one touch the the metal body of this faulty machine , he fell a big electric shock and which may make case of a big injury or death. In this case the phase current use the human body as conductor and start flow from human body to the ground. If that person stand on insulator type of surface and have no link with earth then by touching this faulty machine nothing happened.
So if we connect the a earth wire to the machine body then the phase current start flowing from metal body to the earth my earth wire.
The resistance of earth wire is low from a human body and as i told in my above words that electricity or electric current always flow and chose those ways which have low resistance or in which the current flow can move easily,

Let take an example. In the below example diagram i shown protection of shock in case of earthing system.
earthing system diagram

In the above earthing system diagram i shown incoming supply from supply substation which 220 volts of Alternating current supply. So the neutral wire direct goes to the machine (refrigerator) and phase wire is connect to a 10 ampere fuse and from the fuse it is connected to to machine. The substation is an transformer which secondary connection is in star (Y connection) and on star point a earth wire is connect. So machine have a fault to frame and the phase current start flowing from the frame to earth and this current goes to neutral point of substation through the earth and it's make a strong short circuit which start the over current flow and due over current flow the fuse will be burn or melting.
One thing more in case of installing high ampere fuse or circuit breaker, or connecting machine to low quality earthing system ' the fuse will not melt and when a person tech the machine, the fell a small electric shock or earth leakage current but if the earthing system is too week or the earthing system is high resistance earth then this earthing system can not protect you from electric shock accidents.