How to Replace an Electrical Service Panel (PART 2)
Now that we’ve gotten the enclosures mounted on the wall and the riser built it’s time to install the breakers and tie this service up.
I’ve landed my service entrance conductors into their places, now it’s time to start dealing with the circuit breakers and branch circuits. When this house was wired it was done so by utilizing multi-wire branch circuits rather than individual branch circuits. This is a tad unfortunate, but not the end of the world. It just means getting arc-fault protection on the circuits per 210.12 of the 2020 NEC will be difficult, as it will require very expensive “shared neutral” 2-pole 20a AFCI breakers which cost around $100 each.
For the time being I’m just going to install standard 2-pole 20 breakers so that my multiwire branch circuits have a common trip feature, meaning both circuits that share a neutral will trip if either of the circuits have a problem. The last thing that you want is one circuit having a problem with a neutral and it affecting the other circuit because it doesn’t trip.
I begin landing my neutral (grounded) conductors first. I decide to use a ground bus in the back of the enclosure to land each of my neutrals, and then run a conductor-dependent bonding-jumper to the neutral bus, rather than installing wirenuts and adding jumpers to every neutral in the panel. The problem is that the neutrals are too short for this new larger panel. But by adding a conductor depending bonding jumper I’m able to extend the neutrals up to the incoming neutral and not rely on the enclosure to carry short circuit current in the event of a fault.
I do the same thing for the equipment grounds, I add a bus in the bottom of the panel and connect it to the neutral by a conductor-dependent bonding-jumper. YOU DO NOT HAVE TO DO THIS, THIS IS JUST MY CHOICE TO DO.
Lastly I knock out all of my dead-front tabs and put the panel back together, call the inspector, and power company to come back out and re-energize the service.