Hi Mark,
Thank you again for taking the time to answer my questions and help. But while I've been trying very hard to remain receptive and positive in my replies, I feel a bit like I'm being yelled at. I really do want to understand what I'm doing and be safe - honest.
Thankfully, I won't be running anything inside the walls. If you think it's hard to run new wiring in a fully dry-walled house, you have no idea how difficult it is to do in a 7' x 18' box where the furniture and appliances are all bolted down. I'll be drilling through the floor and running wiring along the underside of the vehicle in a plastic cable protector. That way I only have to work around moving parts, exposure to water, road debris and chemicals, and heat sources like the exhaust.
If you look back you'll see that I've been consistently asking for ideas on protecting the wiring to the relay, since it's a separate parallel circuit and I don't want to run #12 wire to power a 20 milliamp relay.
What do you think of this breaker?
W28-XQ1A-025 If I understand the data sheet, it looks like it would trip in less than .3 seconds if at 2.5 amps.
Do you have any thoughts for low current wiring on how to determine the required gauge?
http://www.engineeringtoolbox.com/wire-gauges-d_419.html seems to indicate that #22 can handle 3 amps, and #24 can handle 2 amps. If I use
Wikipedia American_wire_gauge, the ratio for NEC seems to be 1/11th the Preece ~10s fusing current. That would give #22 gauge a 3.7 amp rating, and #24 a 2.6 amp rating. From either source, with a 250 milliamp breaker, it looks like 22 or 24 gauge wire would be safe even if it's not code.
That would allow me to use
Southwire-22-2-Shield-Security-Cable for the relay wiring. However, that's only 300v. Safe, again because I have a hardwired energy management system (fancy surge protector) which protects the RV against over and under voltage on the shore and generator lines.
If I need to have 600v rated wire, I have to go with something like this:
http://www.mouser.com/ProductDetail/TE-Connectivity-Raychem/44A0121-24-0-9-US/?qs=sGAEpiMZZMv1%2f%252b2kKkGMBR432jei1SPkxrIu7AJt0tY%3dThoughts?