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DIY tips. Do not overload a circuit or the main breaker


Educate yourself before doing electrical work. And do not do it unless you know what you are doing.

It's a hot summer. You have bought a window Air Conditioner. But the cord was too short and you decided to do it yourself and install an extra wall outlet right near the window.

The job is done, you turn it on but in two minutes or one hour the breaker trips and the AC stops. You reset but it happens again and again. Why?

An experienced electrician always asks questions and conducts investigations before he does anything. He finds out how many lights, plugs and devices are already connected to the line. Every branch circuit in the house is able to carry only 15 Amp. And if it was loaded before the AC to, say 12 A and the new appliance took 6 A more, than 18 A was too much for the breaker to handle. It tripped as designed, intended, and expected protecting the 15 Amp wire from overheating and the excessive 18A current, saving the line, you, and your house from burning and fire. You just made a mistake because you did it yourself without knowing what you were doing.

Here is another typical error most people do when they add loads even without installing extra receptacles. If a microwave uses the same line with another kitchen outlets it will overwhelm the circuit when you use a toaster or coffee maker simultaneously. That is why the code demands a dedicated line for the microwave and split receptacles for the kitchen counter appliances.

The older is electrical system, the higher is the probability of overload. This leads to another unpleasant consequence. A panel and its main breaker filled to a maximum capacity could sometimes trip even if you turn on a light fixture. A sudden loss of all power in the middle of extremely hot or cold night is very unpleasant. Organize yourself, turn off all unused lights, devices, buy LEDs, and do not go over the system rating repeatedly.

The best solution for the problem of losing power completely is panel upgrade. The increased capacity will sustain higher total current and enable it to function properly even during the peak hours.

The same applies to properties of any size. Be careful not to go over the main breaker amperage limit. Before adding a 30 Amp two or three phase (240V) cable in a restaurant or warehouse even with a 400A capacity, we always do current calculations first. And so should you.

During the peak times many homes and businesses use 95% or more of all lights and equipment. Adding an extra item could trip the main breaker or blow main fuse. Losing power when you need it most is the last thing you want to experience.

You started with a purchase of the window Air Conditioner. But instead of making life more comfortable, you have created a problem for yourself.

So don't do electrical work if you are not 100% sure about its outcome. And never replace a fuse or breaker with another one of a higher current rating. Using a 20A or 30A breaker/fuse instead of the 15A original one when it trips/blows repeatedly is the simplest yet deadliest mistake.

If you still need more plugs or planing to buy a hot tub, welder, EV charger, baseboard heater, cooktop, oven, etc., call Electrician Toronto to get a safe, worry and problem free code compliant work. We have six locations all over the GTA.


(289) 217-9643
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