Running 2 AC units on 30 amp

time2roll wrote:

myredracer wrote:

We Cant Wait wrote:
Also pulling a full 30 AMPS for an extended period of time could in all likely hood over hear and melt the pedestal plug or your cord plug as shown above.

A receptacle and a circuit breaker are designed to operate at their rating indefinitely.

NEC says for continuous load circuits the supply should be 125 percent of the load. Or rather 24 amps is the maximum continuous load that should be on a 30 amp circuit. IIRC continuous is defined as 3+ hours. Air conditioner is not generally considered a continuous load as it should cycle. In reality we all know they can run 12+ hours without cycling the compressor.

Just some perspective.

To clarify that, the NEC circuit loading only applies to buildings and facilities that have permanent/fixed wiring systems and components and the 80/125 percent rule doesn't apply to RVs. The NEC doesn't cover "portable" plug-in loads and restrict the load relative to the recept. rating it's plugged into. NEC article 551 requires a demand load of 3600 watts (30 amps) for an individual 30 amp RV/site and there is no provision for continuous/non-continuous loads. Art. 551 specifies how wiring within an RV is to be done but does not restrict the total demand on the 30 amp (or 50 amp) shore power connection. I'd post some links to the NEC but can't find a free online version lately.

If you stop and think about it, there is no way that demand in a 30 amp RV can possibly be restricted to max. 80 percent (24 amps). If you added up the available load per branch circuit in the panel, it would far exceed 30 amps. The way you find out if you are drawing too much is simply that you end up with a tripped breaker - you unplug one or more items and reset the breaker and hopefully won't do it again. :) An RV is kinda like an extension cord with a few receptacles on the end of it and it's not possible to restrict how much you plug into it.