Question about trailer electrictity.

Reverse polarity. The trailer when plugged into shore power may be providing voltage along the negative and ground along the positive wiring. It has to be that according to
Nvr2loud on 09/24/13 11:00am

I agree that something is wrong and it shouldn't do this. But, I'm not willing to take a guess on what the problems is from here. You need to find a decent auto mechanic and take him both the truck and the trailer hooked together if he knows his stuff he should be able to find the problem in not too much time.

Oh, and my house has no grounded receptacles. It was built in 42.

I had my trailer battery polarity reversed and it burnt my brake controller. Check your trailer battery polarity. The lights in your trailer will still work if the battery is wired incorrectly.

If everything is wired correctly, there should be no problem.

I would be pretty confident your truck connection is wired backwards though. etrailer.com has the pinouts listed.

Nvr2loud wrote:
Reverse polarity. The trailer when plugged into shore power may be providing voltage along the negative and ground along the positive wiring.

The trailer AND the truck SHOULD have a catastrophic breaker or fuse in place in case of shorts or reverse wiring.

The trailer should have a silver box near the tongue which is the breaker, that protects the trailer wiring from shorts at the trailer battery and the converter also has a fuse which connects to the trailer battery.

The truck should have fuses either under the dash or in the engine compartment which should have protected the truck wiring (unless of course the vehicle was not prewired and someone added the wiring).

Typically connecting a vehicle while the shore power is one should never burn up the vehicle wiring.

You have a definite problem and I would recommend seeking some local help to sort it out...

Well, it seemed the first time I did that at home, a lost a fuse in the truck. Now I unplug from truck while setting up TT and prior to plugging into shore power. I also check pedestal with a cheap electrical tester (3 lites) before plugging in, but also have a better tester plugged into 120v. outlet in trailer. Recently cheap tester showed 2 yellow lites (all good) but inside tester showed a ground fault code, meaning the ground from the pedestal was not there. Way back, older homes never had a ground at the outlets either.

DutchmenSport wrote:

beemerphile1 wrote:
Either your tow vehicle or trailer is wired incorrectly. If the wiring is correct it won't cause any harm.

Unless a wire is loose and it's arcing (sparking) causing excessive heat and eventually a burn-out? Possible theory!

This isn't a loose wire, it is a dead short;

dwkesterson wrote:
It burnt the ground wire completely...trailer plug...to...the cab....

I have left my plugged into shore power and also the truck, no problem was encountered. We did this to keep the fridge cooling because we were leaving out early in the morning. Like has been mentioned, you have a problem somewhere.

Nvr2loud wrote:
Reverse polarity. The trailer when plugged into shore power may be providing voltage along the negative and ground along the positive wiring.

Shore power polarity would have no effect. IF the shore receptacle was wired backwards you may get a shock when touching the trailer since current is flowing through the neutral, but the polarity input to the converter does not affect the polarity output of the converter.

In other words if the converter is plugged into a wall socket, the red output wire is positive and the black output wire is negative. If you unplugged it, turned the plug upside down and plugged it back in, the red would still be positive and the black would still be negative.

IF the output polarity of the converted was backwards, the bathroom fan would blow in, the radio wouldn't work, etc.

More likely there is an issue with the trailer pigtail that plugs into the truck. Look under the trailer tongue for the junction box where the pigtail connects to the trailer wiring. Start there and see what you can find out.

beemerphile1 wrote:
Either your tow vehicle or trailer is wired incorrectly. If the wiring is correct it won't cause any harm.

.... unless a wire is loose and it's arching (sparking) causing excessive heat and eventually a burn-out? ... possible theory!

Either your tow vehicle or trailer is wired incorrectly. If the wiring is correct it won't cause any harm.