'72 Sovereign Land Yacht porch light woes

[3irdeyephoto]

So I got this 31-footer in near perfect condition except the front lounge lights and range hood exhaust fan didn't work - so I replaced the blown 10 amp fuse in the Univolt box and All came back to life! ... but no outside lights So I bought a new scare light assembly and porch light socket as I'd learned that one wont work without the other and soon they both Worked! My girlfriend comes home to a beautiful externally-lit patio and just touches the unattached porch light housing and *spark* there goes the fuse ... after the newly blown fuse is replaced and the housing is firmly attached, I plug in the power and *pop* goes fuse #2.
So after all this stupidity the stupid question is: Why won't the ground wire ground? or What's the best way to secure the ground wire to keep this fuse from popping and keep my outside lights on?

[Minno]

Let me see if I understand this. You replaced the porch light and the scare light. Both worked while the porch light socket was hanging free, but after installing the porch light socket into the housing, the fuse is blowing immediately. Is that correct?

You say the fuse blows as soon as you plug in power. Do you mean the shore power cord? Do you have a battery to provide 12 VDC power without being plugged in? Does the fuse blow before you turn on the light switch for the porch light?

Kinda sounds like you wired the socket backwards. As long as it was not connected to the trailer, it worked ok. But as soon as you installed it, the fuse blows. That's my guess.

Chris

[3irdeyephoto]

Thanks, I'll try and explain in better detail ... I replaced the entire scare light assembly first and no light came on. That's when I learned it shares it's circuit with the porch light. I then wired the porch light with the same white/black wiring arrangement as it was before (white for ground/black for power) the only difference is I didn't solder the ground, I just wrapped it around the bracket and taped it. Both lights worked initially until the whole unit was moved and arced (sp?). I thought it might be due to the cover not being mounted since the bulb socket bracket mounts to the cover and the ground wire connects to the same bracket (confirmed by airstream). So I checked my connections, mounted everything firmly, changed the fuse and plugged in the power and the fuse popped the second I did (because I had left the light switch on?). This is on shoreline power only, no battery at all. Oh, and I didn't have any electrical tape so I used duct tape - could this be the culprit?

[J. Morgan]

I think 3rdeye got it right, the socket is wired backward, regardless of the color of the wires.

Either that or hot wire on the new light is grounded agains the housing.

It is probably the first option.

New does not always mean right.

[SuzyHomemakr]

My '72 Ambassador's porch light is wired backwards, as well! The ground leg is switched... how silly is that?

[3irdeyephoto]

Wow, Suzy! Can you give me more detail? And I don't know, J.Morgan, I took apart the scare light this morning and it only has one wire - it's the power line and it's the black one. Since these two run on the same circuit I'm assuming the black wire in the porch light is also the power. As I mentioned, the white wire was soldered to the old rusty fixture in the porch light so I'm thinking it was the ground because it wasn't connected directly to the bulb socket itself.
I'm gonna try again this time using real electrical tape to insulate the ground wire (and a fresh 5-pack of 10 amp fuses) and will post results ... anybody else have any ideas?

[3irdeyephoto]

Ok, the electrical tape seems to have worked, as well as the wiring order (white ground/black power) Both lights are working again!! But ... now if I try to mount the bracket to the light cover it arcs - is this a materials issue? As in, should I be trying a nylon or other non-conductive screw? Or should I just close it up and leave well enough alone ?

[JCWDCW]

Take the fixture off the wires and check for 12 volts on both black and white wires. It almost sounds like the white wire has 12V positive on it and when you assemble the fixture into the trailer it gets grounded (shorts)

If there is only one wire on the fixture then the ground is meant to be back through the trailer body and you shouldn't need a neutral wire.

JCW

[J. Morgan]

If there is only one wire to the fixture, and you blow a fuse every time the fixture touches the trailer, then it is about sure that the fixture is shorted out.