Thor Forums

[RustyJC]

Originally Posted by bevedfelker

Hooligan's drawing makes way more sense. The adapter is not providing two legs with 50 amps and my 30 amp circuit breaker is limiting the 50 amps to 30. I thought if you apply 50 amps to a 30 amp circuit breaker -- well it pops because that what it is designed to do for an overload of 50 amps on a 30 amp CB.

Being plugged into one hot leg of 120/240V 50 amp service versus the single hot leg of 120V 30 amp service has absolutely nothing to do with how much current your RV draws. Ohms law applies here, and current (I) is equal to voltage (E) divided by resistance (R). If I plug a 60 watt lamp into a 120 volt outlet, it's always going to draw 0.5 amps since its internal resistance is 240 ohms. I (0.5 amps) = E (120 volts) / R (240 ohms). It doesn't matter if I plug that lamp into a 120 volt 15 amp, 20 amp, 30 amp or 50 amp receptacle - it's going to draw 0.5 amps. Likewise, if you have loads on line in your RV that would draw 25 amps through the shore power line, your RV is going to draw the same 25 amps if it's plugged into 120 volt 30 amp or 120 volt 50 amp service.

Originally Posted by bevedfelker

Hooligan's drawing shows that one leg of the 50 amp end does nothing except provide a "neutered" leg to fit the hole of the 50 amp connector on the pedestal. So the real limiting factor with the adapter is that one leg is not connected to anything (thereby not providing 110 VAC at 25 amps). Rather, the one leg that is properly wired provides 110 volts at somewhere around 25 amps.

If that single leg of the 120/240V 50 amp service is providing 25 amps, it's because that is what the loads of the RV are drawing as described above. If not for the 30 amp breaker in your RV, that single leg of the 50 amp service is (by definition) capable of providing 50 amps. Go look in the power pedestal. There are two 50 amp (not 25 amp) linked breakers, one for each hot leg of the 120/240V 50 amp service.

Rusty