RVing message boards > Tech Talk
Fried electrical
nbounder:
Got to agree with John on this one. His scheme is foolproof.
I have done a LOT of troubleshooting over many years, and one thing I learned was that when all the facts are presented, & everything looks perfect, but the damn thing don't work, likely one of the 'facts' is wrong, or you need to ignore one or more of the facts in your analysis.
pilotguy25:
Thanks for the answers to my post. I originally wired a 30 amp receptacle. Long story but I built a metal building to house my motorhome. I was given advice from Home Depot on how to run electrical (30 amps) from my main power pole (that feeds a circuit breaker panel on my house) and the new metal building with its own circuit breaker panel. I was told to run just three wires. Later they told me I should have run 4 wires (two hot, a neutral, and a ground). I then used a two pole circuit breaker on the power pole and a two pole circuit breaker in the new circuit breaker panel. The 30 amp receptacle was wired with two hots and a ground (per instructions from home depot "expert". Apparently 220 volts went into the motorhome. I have since wired a 50 amp receptacle with the two hots, a neutral, and a ground (correctly) as John suggested with 30 amp circuit breaker but with a 50 amp cord and plug. When I plugged it in there wasn't anything electrical applicance on ( no tv, ac, fridge, washer/dryer, etc) Everything was off. Just didn't have anything coming on (the light on the AC light switch, etc). To answer Alfa38user. I am wired for 50 amp service. I have been plugged in many times at campgrounds to 50 amp service. To answer Wizard46. Yes I do think I need a new transfer switch. Just worried why no power at the circuit breaker in the coach when I push transfer switch (contacts) in and am receiving power on the outbound side of transfer switch. What is between the transfer switch and the circuit breaker. By the way when the power was plugged in originally with the 220 volts, none of the circuit breakers tripped in the coach. I also have a power surge hooked up to the transfer switch. Isn't this supposed to guard against errant voltages such as this?
Gary RV Roamer:
Depending on what model of "surge protector" you have, it may have prevented the over-voltage from doing damage. And in doing so it may have sacrificed itself, so you might try removing or bypassing that to see if you get power. But not all surge devices have voltage monitoring - what make and model do you have?
No matter how you did it, wiring two hot wires into a 30A outlet pretty much guarantees you put 220v where only 120v should ever be. Breakers won't trip due to over-voltage - only excessive current will do that. But the over-voltage can still fry electrical components. Chances are good that one of the things fried is a relay or two in the transfer switch.
I'm unclear on what you have to "push and hold in" to get 50A shore power, especially since you say you have no shore power anyway. What is it you are holding in, and how/where are you detecting that you have power when holding it in?
pilotguy25:
Gary,
I'm pushing in the switch inside the power transfer switch causing the contacts to come together. When I turn on the generator the contact hooked to the generator will pull itself together. The shore power contact will not. I'm at work now but I think I remember seeing something like Liebert on the surge protector. I use a voltage meter to see the power before the contact switch and then when I push and hold the switch in I use the volt meter on the "power out" side to verify I have voltage.
teddyu:
Reading the OPs last post, running three wires from the pole to the new subpanel in the metal building was OK. A local ground from the new subpanel was needed to be in compliance with the electrical codes. The 2 circuit breakers at the pole isolates the subpanel; then 2 circuit breakers in the subpanel isolates the receptacle. Hopefully this is the configuration.
Here is what I surmize occurred from the original post: in order to adapt the 30a receptacle to the MH 50a cord, the OP must have used a 50a [L1, L2, N, & G] female to a 30a [L1, N, & G] male adaptor. The adaptor (typically a 1-120v) input [L1] with a neutral [N] and a ground [G] put 2-120v feeds on L1 & N into the adaptor causing a dead short in the female end. All of the breakers and wiring should have been checked. Assuming that everything is satisfactory between the pole and subpanel there should be power to the 50a receptacle.
It is pretty hard to follow the OP second post. Understanding the power input configuration is important in order to help in troubleshooting. Is the output of the subpanel a female receptacle or wiring with a male plug? Is the surge protector in line between the transfer switch and the MH breaker panel? or somewhere else. My surge protector has a time delay (~2min) prior to powering the MH. Is the OP waiting long enough before checking power at the MH circuit breaker panel? I'll subscribe to this post in order to aid the OP. Just my two cents...
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