RV to power home temp

JaxDad wrote:

crawford wrote:
it people could read and see the interlock system it is safe and legal and yes you can back feed by turning off main and locking it out you can legally do it. I been doing it for years and never a problem.

It is absolutely NOT legal.

The NEC requires you use a transfer kit or interlock to abolutely ensure you can't feed power back onto the grid (which would be amplified up to 17,000 volts or so by going backwards through your transformer, by the way).

Turning off your mains also doesn’t completely disconnect your house either, it only breaks the two hot legs, the neutral bond remains. This could create potential in lines that the people working on them think are dead and therefore safe.

There’s a reason the cords used to connect this way are called ‘suicide cords’ or ‘deadman cords’.

I assumed (lacking any other information) that the interlock being described was NEC approved for that purpose. There are approved interlock kits that physically prevent the main breaker and the generator feed breaker from being turned on at the same time. (Here are some available from Home Depot.) Such kits, of course, aren't used with a suicide cord and a branch circuit, but require a dedicated generator power inlet or hardwiring the generator.

Having the neutral connected with the hots disconnected does not pose any threat of backfeeding the grid. You can't have a circuit with a single wire, and without a circuit there's no power transfer. Indeed, since the neutral is bonded to earth ground, it can't even rise or fall in potential very much at all.

An RV transfer switch has to switch the neutral because it is switching the neutral/ground bond (bonded at the onboard RV generator, not bonded for shore power), biut that's not a concern for a sticks-and-bricks house where the bond is at the main panel in both cases.