Hello, I am inspecting the electrical panel in my home as part of the training course, and I need help understanding how the wiring on the breakers work. I’ve included 2 photos below for reference.
In the 1st photo, at the bottom are four 20-amp breakers, and each one has 2 setscrews, with a hot and neutral wire attached in each of those breakers. Then behind those breakers, there’s a white wire coming from the breaker and attaching to the neutral bus bar.
In the middle there is a 15-amp and two 20-amp breakers. Each of these only have one setscrew with a hot wire connected. The neutral wires from those circuits are attached directly to the bus bar.
So my question on the 1st photo is, why do some breakers have 2 setscrews for both hot and neutral, and other breakers have 1 setscrew for hot, and the neutral conductor goes directly to the neutral bus bar?
On the 2nd photo, you can see 15-amp breakers with hot and neutral conductors leading to them. Then there are conductors going from the breakers to the neutral bus bar, but those conductors are much larger diameter than the 14 AWG leading to the breakers. I’m guessing maybe the electrician just used larger-than-needed wires due to what he had on hand. Do you think the wire leading to the neutral bus bar would normally be subject to the same rules for sizing as the wiring in the branch circuit?
The electrician didn’t install those larger conductors they are an integral part of the circuit breaker and are installed at the factory. In answer to your second question the answer is no they do not have to follow the conductor sizes based on the NEC.
If you think about the AFCI or GFCI breakers as an operating device, they each require both a Hot and Neutral to operate their circuitry. Conventional breakers do not. Code changes now require switch boxes to contain neutrals also. The reasoning is that smart switches also require a hot and neutral to operate their circuitry. (in the past and most installations the switch needs only to make or break the Hot to the light fixture).
