August 2016
A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
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.

  
A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
Today you will learn how to test battery with multimeter , as you know that a multi meter is an testing device or meter which we use for multi testing, but as you know that battery are numbering in those electric devices which have a history and and which we use more then other devices. In daily life we use batteries in our cars , we use in our mobile phones and laptops etc. There are different types and shapes of batteries. Some we use for high load and some we use for low load. Some batteries are big in size and some are Small.
But the batteries have a life and expiring date, for example we use batteries with inverter / UPS for emergency power supply. A high quality brand batter work very well with an inverter for 2 years. A car battery have also a time of life, some batteries work for 1 years and some are work for 2 to 3 years. However the better life is depend on the quality and it's type. Today i am writing about how test batter with multimeter. In the post you will learn the testing of batter by using the analog- and digital multi meter.


How to test battery with multimeter

The testing of batter with multi meter is too simple and easy, you can easily test you battery with multi meter by setting the multi meter knob on DC volts. But note that if your testing an 12 volts battery then set the knob on option which is design for 1 volts to 12 volts or higher. i.e if your are testing an mobile batter of 3.7 volts then you can set your multi meter on 5 DC volts or 10 volts testing option. But this is only for the analog multi meter. In digital you have some option like 10, 50, 200, 600 DC (direct current) volts etc. So if your are testing a better of 12 volts the you can use the 20 or 50 volts option in your digital multi meter.

Now come to the step one if your are testing a battery which is 12 volts then you can easily test your battery by using an analog or digital multi meter. You need a multi meter in which DC volts testing option available. Now set your multi meter knob on DC volts testing. Connect multi meter red lead to the positive terminal of battery and black lead to the negative terminal. Now if the meter shown 12 volts then your battery is good contention-, however the better checking method is that to test your battery during using time . My mean connect a 12 volt fan to battery (a car engine coaling fan) now test your battery, now if your battery volts reading or 11.8 or 11.9 or steel reading are 12 volts then it's means that your battery working state is good or it's is a good battery. And if the battery shown 5 or 6 volts and your fan are also running slow then charge your battery and after fully charge. Check it again if it's shown the same problem or have a short- backup then it's mean that your battery life is over and this batter is not good working state. The better option to change this battery.

Do follow the same method which i told in my above words and which i shown in the below diagram.



In the above test battery with multimeter diagram, i only shown the method of testing battery with a digital multi meter, and i shown a car battery testing. I set the meter knob on 20 volts range and i check a car batter which is 12 volts but you can also check your mobile battery by using 20 volts option in digital multi-meter.
So the above diagram i shown how testing a car battery using digital multi meter . Now come to do it piratically.


  • First of all set your meter on DCV or DC voltage testing. As i shown in the below image.

multimeter use


Now connect the negative lead to the negative terminal of batter and positive (red lead) to the positive terminal as i shown in the below image of testing battery by using digital meter.

multi meter leads to battery


Now the see the reading

dcv multimeter reading


How to test battery with analog multi meter


The testing and setting method of both meters are same, First of all set your meter on DC V testing and then connect the black lead to batter negative terminal and red lead to the positive terminal of battery. As i shown in below images test batter with multimeter.
  • Step one Select DCV by using the knob
dcv multimeter testing

dcv multimeter


  • Step 2 connect meter leads to battery as i shown below.
car battery testing

car battery voltage

  • Now read the volts as i shown in below image
car battery dc volts test by multimeter

Also read Below

How measure AC voltage by Digital multi meter
How to test AC voltage by multi meters
What is a Multi meter


The testing of a mobile battery is also same just like a testing of a car battery however IN SHA ALLAH i will write about the testing of an mobile battery in my incoming posts. Now i hope you lean about test battery with multimeter , however if you have any question regarding the post then ask me in below comment section.
A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
I Published a number of post about the voltage meter wiring and measure voltage. Measure ac voltage is one of them and in this post i am gonna to show you a complete method of measure ac voltage with a multimeter. In this post you will learn completely that how to measure ac voltage with a multimeter. In one of my last posts i write about the testing AC Voltage using a digital meter with images and complete method and in this post i am gonna to tech you about measuring ac (alternative current) voltage using analog multimeter with step by step.



How To Measure AC Voltage With A Multimeter?


As you know that a diagram is very important for better understanding, i also shown below how to measure ac voltage with a multimeter with practical examples, however to understand clearly i design a diagram which work better for you. In the below measure ac voltage with multi meter diagram i shown a analog multimeter which i set on testing ac voltage 250 volts and i connect the leads to the electrical outlet.

how to measure voltage with a multimeter


Now let's Do it practically step by step.

The measurement of ac voltage process is too simple , first of all insert the multimeter leads to negative and positive terminal. (black led to negative - and red led to positive +) as i shown in below image.

Measure AC Voltage


Now by using the multimeter knob select the AC voltage . If you want to test voltage above form 250 volts then set the knob on 500 volts . However in multimeter we have different option for AC measuring voltage, like 20 volts, 50, 250, 500 and 1000 volts. I select the knob on 250 volts because i testing voltage between phase and neutral and if some one want to test voltage between the 2 lines or two hot wire then 500 volts option work for that measurement.
Now come to the next step... Set the knob on AC 250 volts as i shown in below image.

testing ac voltage with multi meter





After that inter the multi meter leads testing points to the outlet or connect to the point where the voltage is available as i shown in below image.

measurement of ac voltage


testing of ac voltage in outlet


Now lets see the reading,  the multi meter shown the the incoming voltage is 230 volts. This is too simple to measure ac voltage with a multimeter. I shown the reading of multi meter in below image.
reading of multi meter during ac voltage measurement


Measure AC voltage Using Digital multimeter

I already published a post about testing Alternative current voltage using digital multi meter and you can find out by the using the below links but the best option to read all the below link posts to understand it completely.

How to test AC voltage using Digital multi meter (complete Guide)
What is multi meter and it's uses
How to wire an outlet?
How to connect voltmeter in home wiring?

Message :

I hope you understood it completely and now if you have any question in yours mind regarding measure ac voltage using multi meter then you can ask me by using the below comments section.
A platform to learn electrical wiring, single phase, 3 phase wiring, controlling, HVAC, electrical installation, electrical diagrams.
In this post you will learn about the fridge thermostat wiring diagram and instillation, as you know that we use refrigerator in our daily life, in refrigerator / fridge we have knob switch which is a movable switch from which we can control the coldness. We can easily make colder or cool from this knob. This is called thermostat switch and in this post you will learn about thermostat wiirng connection complete gudie which is a very simple connection. This connection is done in every refrigerator and air conditioner , There are different types of thermostat switches regarding wiring connection and regarding temperature.
The working of thermostat in refrigerator / fridge or air conditioner is that switch off the compressor when the machines complete the coiling range.



Fridge Thermostat Wiring Diagram - Fridge Thermostat Connection

In Thermostat switch we have two types of connection, in which one is for main and other for out going to compressor, in some thermostat switches we have main or common connection with two terminal in which one is for incoming supply and other one for light.
In some thermostat we have only two connection in which one is for incoming and other on is for outgoing to load or compressor.
fridge thermostat wiring connection is done in series connection, my means that this instill between compressor and supply current.
In fridge, the supply one wire goes to the ptc relay and other one goes to thermostat from which the 2nd wire goes to compressor. Direct cool refrigerator and no frost refrigerator wiring is different but if we talk about fridge thermostat wiring diagram and connection , so this same in both.
Now lets' the below fridge thermostat instillation / connection diagram for completely understanding

fridge thermostat wiring diagram

In the above diagram i shown how to wire a ref thermostat, but this only a basic diagram and we will publish complete refrigerator diagram soon. However from this diagram you get an idea about fridge thermostat instillation . On thing more in above fridge thermostat diagram i shown electric plug which is refrigerator plug and from which i connect one wire to compressor and 2nd to thermostat switch and from thermostat i connect it to compressor. In compressor we use PTC relay and overload protector which are also important parts of refrigerators, so for better understanding kindly read the below posts.

Also read below
How to identify compressor terminals?
What is overload protector and it's working?
What is the role of PTC Relay in refrigerator?
Refrigerator not cooling problem and salutations

I hope after this article now you will completely understood the fridge thermostat wiring diagram / connection. However IN SHA ALLLAH soon i will design complete ref / fridge diagrams.