If you are wiring something you may want to get one of those wireless thermometer guns. I didnt have one at the time, but used my hand the old fashion way to check temp. Notice the orange extension cord I used to plug in my enginer phev kit was warm to the touch. Got a good deal on a 10 gauge extension cord. It was cool to the touch and my charger was 45 minutes quicker at charging my battery pack.
I then used the 2 cords on a leaf vac/shredder. The orange cord made it work, but performance was lacking. The yellow 10 gauge cord it was sucking up rocks, sticks, etc. That day I grabbed all the extension cords we had for outdoor use and tested them in this manner. I tossed 14 cords, kept 2. I then made a few trips to harbor freight to buy replacement 10 gauge extension cords.