I do wood working in my garage. I have two saws a miter saw and a table saw. About 1 in 10 times when I start either of the saws the circuit breaker will immediately trip. Nothing else is running on the same circuit at the time of the trips. They have never tripped after startup, including when actually cutting wood. The breaker is a 20 amp breaker. I attached an image of it and a label of the panel. The outlet is GFCI, but its not the GFCI tripping its the breaker. Their cords dont reach the outlet, they are plugged into this extension cord.
What are possible solutions to stop the breaker from tripping? I read about trip time delay, is there a way to identify the trip time delay of my current breaker? My guess is the solution will involve messing with the panel which I am not comfortable doing and will get an electrician to do, but I am interested to know what they might do. Also interested if there is anything I should try before calling an electrician?
Thanks
Best Answer
I believe your problem is the extension cord. Is there any way you can locate the saw(s) so that they can be directly plugged into the outlet?
What happens when you use an extension cord with an induction motor (which is almost certainly what you are dealing with) is that there is an initial surge of current until the motor builds up a resistance (called back EMF) as its magnetic field starts to stabilize. When you use an extension cord there is voltage loss across the cord and so it takes more current to generate the back EMF.
Another possibility is to get yourself a heavy duty extension cord so as to minimize the voltage drop due to the cord. These are generally more expensive since they contain larger copper conductors but may help resolve your problem. I realize your cord is marked as "heavy duty" but it's a 12 ga cord. A 10 ga cord is probably a better choice here.