50 amp to a 30 and 20 out how to do? HELP!
I'm adding a second ac to my WW trailer, it has a 30 amp service, I am wiring the 2nd ac with seperate wiring and load center and breaker out of the load center will be a plug for the ac. I was looki...
Forum Discussion
Gil made some good points. But here is a newer point that may be rather rare yet.
You may not have 240V anyway. In some parks, you may run into a 50amp service that is two, 25amp, protected circuits of the same phase giving you "0" volts between the two. In residential services, the 240V comes from the voltage between two different phases. In commercial power distribution, the power companies change phase paring in residential areas to equalize load management. But every house has two different phases (AB, BC or CA). Within RV parks, it seems they're starting to do their own oddball phase load management since 240V isn't generally needed in RVs that I know of. I don't know about the small RV electric cloths dryers, I don't have one. But I suspect they run on only 120V.
The parks might just bring one phase to a slow blow, 50A breaker that's imbedded in the pedestal and feed the entire pedestal from that. If it's a dual pedestal, they may feed one side with one phase through an imbedded 50A breaker and the other with the other phase through another imbedded 50A breaker. They might feed one phase to odd number pedestals, or spaces, and the other phase to even pedestals.
If you check on the pedestal with a multimeter from one hot side to the other on the 50A receptacle and read "0" volts, you have the same phase. Then read from one side to the hot terminal on the 30A service and so on. If you read "0" volts between all hot sides, you have all of one phase. This assumes of course, the pedestal is hot as it should be. You can measure hot to neutral and/or ground first to make sure.
The benefit to the park of doing it this way is they can easily prevent guests from pulling any more than 50 amps no matter how a guest tries to get around it. The guests would not have access to the imbedded 50 amp breaker and would have to call park management to have it reset, if it isn't automatic. Since larger units today are becoming more and more power hungry, some folks trip a breaker when using the microwave on a hot summer night and try to get around that by "creative electrical engineering" and plugging one AC unit into the 30A or 20A service. They turn on the microwave and will still trip the imbedded 50A breaker.
I would expect to see more and more new parks wired this way. If guests are abiding by park rules, they should not have any problems except for the rare weak breaker. Breakers do wear out and get weak over time. But other than that, no worries mates.
You may not have 240V anyway. In some parks, you may run into a 50amp service that is two, 25amp, protected circuits of the same phase giving you "0" volts between the two. In residential services, the 240V comes from the voltage between two different phases. In commercial power distribution, the power companies change phase paring in residential areas to equalize load management. But every house has two different phases (AB, BC or CA). Within RV parks, it seems they're starting to do their own oddball phase load management since 240V isn't generally needed in RVs that I know of. I don't know about the small RV electric cloths dryers, I don't have one. But I suspect they run on only 120V.
The parks might just bring one phase to a slow blow, 50A breaker that's imbedded in the pedestal and feed the entire pedestal from that. If it's a dual pedestal, they may feed one side with one phase through an imbedded 50A breaker and the other with the other phase through another imbedded 50A breaker. They might feed one phase to odd number pedestals, or spaces, and the other phase to even pedestals.
If you check on the pedestal with a multimeter from one hot side to the other on the 50A receptacle and read "0" volts, you have the same phase. Then read from one side to the hot terminal on the 30A service and so on. If you read "0" volts between all hot sides, you have all of one phase. This assumes of course, the pedestal is hot as it should be. You can measure hot to neutral and/or ground first to make sure.
The benefit to the park of doing it this way is they can easily prevent guests from pulling any more than 50 amps no matter how a guest tries to get around it. The guests would not have access to the imbedded 50 amp breaker and would have to call park management to have it reset, if it isn't automatic. Since larger units today are becoming more and more power hungry, some folks trip a breaker when using the microwave on a hot summer night and try to get around that by "creative electrical engineering" and plugging one AC unit into the 30A or 20A service. They turn on the microwave and will still trip the imbedded 50A breaker.
I would expect to see more and more new parks wired this way. If guests are abiding by park rules, they should not have any problems except for the rare weak breaker. Breakers do wear out and get weak over time. But other than that, no worries mates.
