Quote:
Originally Posted by schwarz633
If you're combining circuits and/or even moving circuit breakers you have to be aware of the possibility of two circuits "sharing" a neutral. These are called a multi-wire branch circuits. The dead give away will be a 3 wire romex connected to two circuit breakers. But if you've got conduit things can get a bit elusive.
Each of these circuits needs to be on opposite legs of the panel. Breakers across from each other will be on the same leg, but on alternating legs from top to bottom. If you don't do this, there is the potential of overloading the neutral by 2X. I believe in recent times the two breakers needed to have a handle tie between them, but it wasn't always like this.
Also, if you disconnect the neutral on a multi-wire branch circuit you will send 240V across both 120V circuits in series. Depending on the balance of loads on these circuits, each of them may see anywhere from 0-240V and something will get toasted. Ask me how I know.
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My house was re-wired with Romex. I haven’t come across any MWBC but will check more carefully for it.
Thanks for this discussion and suggestion. If I can combine some circuits then I may not need to expand at all.
Thinking about it, I just need to free up room in the main panel for two new 240 v circuits (one for each dual head minisplit) and one more 240 v circuit (to move my espresso machine from the subpanel into the main panel).
The purpose of moving the espresso machine to the main panel is to have all the circuits I want to run through the generator transfer switch together in the main panel, to make the transfer switch wiring tidy. I want the generator to power the heater furnace blower, water heater blower, espresso machine, kitchen lights, kitchen outlets, range (gas range but needs power for convection oven), and maybe one other circuit that my internet and WiFi will be on.
So during power outages, I’ll be warm, have hot showers, internet, be able to cook with the gas range, and be able to pull shots and make lattes and tea. Circuits allowing, I may wire up a single exterior outlet so as to afford my neighbors a grudging extension cord so they can charge their phones as they huddle miserably in their cold houses, BwaaHaaHaa!