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[drcampbell]

Originally Posted by ryano2121

I wired a trailer with 110V power. I have a female plug on the outside of the trailer I use to plug an extension cord from a generator to. ... What is wrong here?

First, you have the wrong gender connector.
This is the connector which should be mounted on the outside of the trailer. It's called an "inlet".

I recommend that you immediately disconnect all of your 120-Volt wiring, then request the on-site assistance of someone who knows what they're doing. What you've done is dangerous.


As for the GFCI tripping, the most likely defect is the grounded (white) wire in the trailer being connected to the trailer frame ground.

If the fusebox you've installed was designed for a building, not a trailer, it is likely that there's a bonding screw in there which connects the W terminals to the box. Remove that screw.


The next-most-likely defect is compromised insulation on either the hot or white wire(s) causing a current leak.

To test for a current leak, unplug the trailer's 120-Volt plug. Use an ohmmeter to check for any continuity between the trailer plug's grounding (G) pin and the grounded (W) blade, then check for any continuity between the grounding (G) pin and the hot blade.

If either test reveals a continuity 20,000 Ohms, (or less) the GFCI is tripping because you have a 6 milliAmp (or more) current leak, which is precisely what GFCIs are supposed to do. Find that current leak and insulate it properly.

Although it may "work" on a generator, it's unsafe.

The hot & grounded (white) wires being reversed will not cause a GFCI to trip if that's the only defect in the trailer. As long as the outbound and inbound currents are the equal, (no current diverted to ground) a GFCI is satisfied.



This is the face view of a NEMA 5-15 (125 Volt, 15 Ampere) receptacle.
(courtesy of levitonproducts.com) The plug will be a mirror image.

The terminal labeled "G" carries the "grounding" conductor and is identified by green screw terminals and green or bare wires. It connects to a ground rod buried in the Earth and doesn't carry any current when all's well.

The terminal labeled "W" carries the "grounded" conductor and is identified by white-metal (silver-colored) screw terminals and white or tan wires. It is grounded at exactly ONE point in the building's service entrance, no more, no less. It is a current-carrying conductor and carries however much current your trailer uses. It is not a "neutral" conductor; there is no such thing as a neutral conductor in a single-phase system.

The remaining terminal carries the hot conductor and is identified by yellow-metal (gold-colored) screw terminals. In residential work, the wire is often red or black but may be any color other than green, white or tan. It, too, is a current-carrying conductor and carries the same amount of current as the grounded (white) conductor.

Although named "grounded", the white wire(s) must not be grounded anywhere in the trailer. It must be grounded at exactly one point, at the building's service entrance. (strictly speaking, that's called "bonding", not "grounding". For the complete scoop, see the National Electrical Code, Article 250 – Grounding and Bonding.)