A power distribution box would be nice for connecting different loads to a generator at an off-grid job or camp site. But commercial units are big, heavy, and expensive, and they offer some features I don't need, while lacking some of the connections I'd like.
Could I build a safe, simpler, cheaper version of this myself?
My generator is rated for 40 A peak, 30 A continuous. Its 240 V output is on a NEMA 14-50 receptacle with a 40 A breaker. Like the commercial products, my box would have a suitable generator inlet, and I'd connect the generator to the box with an extension cord.
I'd like a distribution box with another 14-50, a duplex 5-20, a 6-50, and maybe a 6-20. I anticipate using the box with other equipment that needs to be sheltered from weather, so while a weatherproof enclosure might be nice to have, I don't require it.
What would make a suitable enclosure?
What should I use as connectors internally? I've seen terminal blocks but not with insulated jumpers rated for this current. I've also seen set-screw connectors with a cover that looks like a wire nut.
My understanding is that the generator breaker will protect my box from overcurrent, but should I use GFCI outlets for the 5-20s? Is there other protection I should incorporate? Any opinions about the usefulness of a power switch at the box?
Should the components be rated for 50 A like the generator outlet, even though it's on a 40 A breaker? Is there some standard derating applied here?