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Re: 50 amp to a 30 and 20 out how to do? HELP!
I don't know what the code is for RV site services. A friend of mine ran into this fairly recently after a discussion on electrical services. Just out of curiosity, he checked the service he was plugged into at the time and discovered his two 25A circuits were on the same phase. He had voltage from hot to neutral on both circuits and "0" between the two. Of course you know this must mean they're in phase since any phase difference would show some voltage difference between the two. He didn't look into this any further before they left the next morning, and since it was of no consequence to him at the time anyway. He just thought it odd enough to comment to me during a recent conversation on the same subject. I don't know how the pedestal in question was wired internally. Nor do I know if others in the same park were like this one. I made an estimate on how it might be wired to get the results of the same phase on both circuits of a 50A service. Perhaps there have been changes in the code that might allow this, something the park manager did himself without knowing the code, or perhaps an honest error by someone else that should never have been working on a power pedestal. It is only 50A at 120V which really isn't that much for one conductor to the pedestal. I don't know. My friend is a retired Radar Engineer and I trust what he told me to be accurate. He's actually sort of anal that way. He probably took his oscilloscope to the pedestal for a better investigation. lol727Views0likes0CommentsRe: 50 amp to a 30 and 20 out how to do? HELP!
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.727Views0likes0CommentsRe: First 5er, Weight Questions
If you subtract the trailer "GVWR: 13,920 lbs" from the "20,000 GCWR" for the truck, you're left with only 6,080 pounds for the truck. To be honest with you, I would suspect the empty truck weighs in somewhere near that figure. Would it not? Going over the MGCWR for the truck is never a good idea IMHO.532Views0likes0Comments
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