How to Wire Reset Thermal Overload Protector?

Nowadays protection is very important in electrical works, and for different Electrical appliances we use different methods and different devices for protection, today i am writing about overload protector and it's wiring. In this post i am taking about automatic reset thermal overload protector which we use for single phase load. This overload we use to make safe our electrical devices from over current flowing.

Some Thing about Thermal overload protector relay

Today in which type of overload i talking, is a type of overload switch which is cut off the electric supply in case of over current flowing. This device is also called reset thermal overload switch. Mostly we use this device for single phase power supply, and i also published a post about refrigerator overload and it's working principles and this overload also working same like refrigerator O/L protector.

Also read below

How to Wire Reset overload Protector Switch

The over current overload protector wiring is very simple, and many places for single phase / one phase supply we use it in series connection between supply and the load. In the below diagram i shown a overload thermal protector which i wired in series connection. I shown the incoming AC supply and out put supply. I connect the L (phase) wire to protector and then i get the supply form O/L protector to the load as i shown below.
overload protector wiring

In the above diagram i shown 20 A (ampere) overload and when ever it's trip you can also reset by pushing reset switch.  When ever some over current flow from it's range it's will cut off the Electric supply and make his contacts open. Note that always use these overload regarding your load. If your overloading current 10 A and you use 20 A then it's will not trip until it's reached to the 20 Ampere.

Sikandar Haidar is a hub of electrical and electronics tutorials and easy diagrams.


  1. Hello, thanks for your explanation. How do I stop this from tripping off. It wouldn't stop doing this since about 4 days now, and it's really annoying. I don't have any water to use. It keep tripping off at about 3 seconds after pushing it back in. Please help before I break it.

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  3. the electric supply in case of over current flowing. Someone To Write My Essay For Me This device is also called reset thermal overload switch.

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