We wired in the electrical panel today using an eight space 125 amp rated subpanel. This is still a lot bigger than it needs to be but is actually quite modest compared to what I’ve seen in other tiny houses. While I agree that it does make sense to separate some circuits and also to follow standard electrical codes for the most part, strict adherence results in an oversized panel, a lot of unnecessary wiring runs, and a lot more circuits than you need in a tiny house.
Our overall electrical strategy was to keep it small, simple, and safe with room for future off-grid tie ins. Our main service is a 10/2 wire coming off of an RV plug and feeding the panel through a normal 30A breaker. A AWG jumper wire connects both legs of the hot bus bars. We added a separate ground bus bar to isolate the ground from the neutral as is required in any subpanel. Our water heater is also on a 30A breaker. A 15A AFCI breaker feeds the lights and bedroom outlets. A 20A dual AFCI / GFCI feeds the under counter outlets and outdoor outlet. Another 20A combo AFCI /GFCI feeds the countertop outlets and the bathroom light and fan.
I always try to be as focused and meticulous as possible when doing electrical work. I want my wires to be well supported, cleanly routed, strain relieved, and clearly marked both inside and outside the box, and on the panel as well. All connections should be triple checked for tightness and checked again after moving the tiny house. It’s important to understand that residential electric codes were never designed with the possibility of a five hour long simultaneous earthquake and hurricane in mind, which is exactly what moving a tiny house can be like on the structure. It’s not hard to imagine that kind of vibration loosening the electrical connections, creating an arc fault and starting a fire. It’s for this reason that doing good work and paying for AFCI breakers is so important. Always remember that the life of everyone who will EVER use your tiny house is in the hands of whoever is wiring it. I have a lot more to say on the subject so make sure to watch our channel for a YouTube video in the future.
NOTE: We changed how our box was wired when we decided to switch to 50amp service, see our other electrical posts for more details.