Any Electricians Out There?

I've installed 2 halogen lights in my backyard today. There were a white, black and ground wire coming out of the light BUT there was also a ground wire on the mounting.

I hooked up the ground wire on the mounting to the house ground and the lights worked fine BUT:

I couldn't finish the installation because the electrical box had a 3 inch gap between the screw holes and the light's mounting was 3 1/2" wide. SO:

I bought crossbars with tapped holes and used those to mount the lamps to each box. NOW:

The d**n lights don't work after I put them back together again.

Why the crossbars make a difference I really don't know BUT should I now take the ground wire from the light and connect that to the house ground and forget about the ground wire from the mounting or should I connect either ground wire directly to the crossbar?

It doesn't make any sense to hook up both ground wires but I'll try that too if necessary.

Any input is really welcome.

Marty

I'm not sure about the box. Maybe you have the wrong size.

I will explain the wires though. You have three wires. The black wire is the ungrounded power conductor also called the hot power conductor. The white wire is the grounded power conductor, also called the neutral wire. These power conductors should be used to power the light.

The green or bare wire is called the grounding conductor, also called the safety ground. This should never power anything. It should be connected to all metal electrical enclosures. It's purpose is to insure that the metal enclosures are always at ground potential, so you won't fry yourself if you should touch the metal while standing in a mud puddle, if there should be some kind of short inside the box.

The green/bare grounding wire should always be at ground potential. If it isn't, there is a wiring fault. The white wire will be somewhat above ground when it's conducting current. Every wire (except a superconductor) has a voltage gradient (voltage drop) when conducting current.

eluminator

Thanks for the info but why do I have two ground wires on the light and its base? Should the light's ground go the house ground or to the crossbar. Should I ignore the ground on the base?

Marty

I'll let other chime in on the ground issue(s). But, with a valid white and black connection the bulb should light up. If not, check: breakers, fuses, switches, connections, bulb, etc.

I'm confused. Send pictures. If there is a ground fault interruptor (GFCI) in the circuit, and you have the grounds wrong, it will probably trip.

Like turbodog said, if you have the black and whites connected, and the safety grounding wire isn't hitting one of them, it should light.

If there is a black wire coming from the light, it should connect to the black wire feeding it. It should connect to nothing else, unless there is a switch. Same goes for the white wires, but of course, you shouldn't switch that one.

The green/bare wires should be connected too. But if there are any metallic enclosures there, they too should probably be connected to this grounding wire. When you are done, for safety sake, all exposed metal, if any, should be securely connected to the grounding (green/bare) wire somehow.

Sometimes old wire will break within the insulation when being flexed during work such as you're doing. This is a rarity but I thought I'd throw that out in case you don't find a more common problem. Try eluminator's and turbo's suggestions first and post your results.

If you are splicing wires with wire nuts, and you aren't practiced at it, it's easy to end up with no electrical connection there. Especially if you are splicing stranded wire to solid wire.

You need the right size for the job.

There are lot's of ways to splice the wires. If you are good with a soldering iron, that would do it. The black and white wires could then be wrapped with electrical tape, or use the wire nut.

You do need the wire nut or some mechanical connection for the safety grounding wires though, according to the code. Solder isn't enough there. They make little brass split bolts for such jobs and I prefer them. At least you can see what the hell you're doing. Unless you have x-ray vision it's hard to tell what's going on inside those damn wire nuts.

The reason for separate ground wires on lamp and housing is likey that something inside the lamp may be electrically isolated from the housing, but still needs to be grounded. Those 2 ground wires should be tied together with the house ground.

The crossbar shouldn't make a difference here electricly. The hot (black) and neutral (white) are all that are strictly needed to make the circuit complete (the grounds are for safety). Since this is outdoors, chances are good that there is a ground-fault interupter outlet or circuit breaker in this particular circuit. If it isn't properly grounded, a ground-fault may be detected and trip the GFI breaker, thus no power. Check your outdoor outlets to see if they are GFI outlets, and if one is tripped (or the breaker box).

Of course this all assumes that you've pulled the light fixture and removed the wire nuts to see if the wires are still twisted together. The proper way to make these connections is to twist the bare wire ends together with a pliers and then screw down the wire nut.

Really... I just got through installing about 5000 wire nuts and every box (all different sizes) said to NOT pretwist the wires. Proper way it said was to strip them, insert them, twist away till the wire outside the nut showed two conplete twists.

Hammer

As soon as there's light in the morning, I'll check all of the connections and consolidate the ground wires as well as look for any GFI outlets outside (I don't think so).

I've already looked at the GFI outlets inside that are on the same circuit and they didn't trip (neither did any of the breakers).

As usual, a seemingly small job has turned into a full days work /ubbthreads/images/graemlins/smile.gif. I had to abandon this job because someone came to install a new built-in microwave and trash compactor and they needed the kitchen lights on, which are on the same circuit as the outdoor lights that I'm messin' with.

I really appreciate everyones input on this silly little problem.

Marty

turbodog

I just looked at my large box of twist-on wire connectors and it says to hold stripped wires together with ends even;pre-twisting unnecessary.

Marty

Thanks for all of your suggestions.

I went outside at the crack of dawn and disassembled the lights. I stripped the wires down to an acceptable 3/4", attached all of the ground wires to the house and used NEW twist-on connectors.

Both lights work great. I can't wait for another 10 hours for darkness so I can adjust the beams /ubbthreads/images/graemlins/smile.gif

Marty

Yea! Isn't it incredible how so many quick & simple jobs are anything but Q & S?