Why is 40 Amp Circuit Breaker Used with 10 Gauge Wire for Universal Wiring Kit

Updated 03/20/2023 | Published 03/19/2023

Question:

Hi etrailer, I was looking at your ETBC7 7-way harness kit. It listed #10ga wires. Is the Black wire in the black/blue bundle awg#10ga? It shows this is connected to the 40A fuse to the battery. The run from the battery to the 7-way connector is about 12 feet. From looking at wire current ratings everything says 40A should be #6awg wire. You guys are the experts and the kit is designed with 40A rating it just seems awg#10 is too small to carry 40A 12 feet. What am I missing?

asked by: Richard D

Expert Reply:

The 40 amp circuit breaker included with the Universal Installation Kit # ETBC7 is installed really close to the vehicle battery which is why it's rated for higher amps. True, by the time it reaches the back of the vehicle the amperage will be lower, but if we placed a lower circuit breaker up by the battery it would trip at times when we really don't want that happening.

Hopefully this helps clear things up for you! Let me know if you end up having any other questions.

expert reply by: Jon G