Quote:
Originally Posted by SAABDOCTOR
they should both be 120v
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Well, yes and no. True, Barney? The way the RV is wired, both the 30 amp and the 50 amp "act" as 120VAC. But the 50 amp does have two hot leads (red and black wires), both at 120VAC and at 180 degrees opposite in phase polarity. So technically, across the two hot leads of the 50 amp, there is 240VAC along with a neutral (white wire) and a ground (green wire). The campground usually puts a 50 amp breaker on each of these hot leads and the two breakers are ganged (joined) together. If you look in the RV's circuit breaker box, there will be two 50 amp master breakers (usually in the center of the circuit breaker panel) that control each hot lead distribution to each side. If you took a multimeter and measured across the two hot leads, you would find 240VAC. Measure across one hot lead to neutral . . . 120VAC. Same for the other hot lead and neutral.
So, technically, a 50 amp connection allows 50 amps per hot lead. If you use a 30 amp to 50 amp adapter (aka, dogbone), the single phase 30 amp hot lead is connected to both 50 amp hot leads inside the adapter. So out of the adapter, you only have a total of 30 amps available, single phase alternating current.
It's all in the wiring. The way the circuit breaker box is wired, one only sees 120VAC inside the RV. This is also a reason, if you have 50 amp service in your RV, and two AC units, you want each AC unit on different hot leads of the circuit breaker box. You probably don't want both AC units on the same side (hot lead).
I do understand that some RVs do utilize 240VAC from 50 amp service for the air conditioning. But I am not aware of any Keystone models that utilize this service.
So, yes, Barney is correct - from the typical RVer's perspective, the 50 amp service supplies only 120VAC power. However, you might want to be aware of what's behind this power.
Ron
Barney - congratulations on the new lifts!