Outdoor Wiring

Old 07-30-02, 03:47 PM
Doug Lon
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Outdoor Wiring

I just had my front walkway redone. A new pier at the end of the walkway has a new fixture. However, when I rewired the fixture, which is connected to a timer inside the house---- the timer controls a hanging fixture outside the front door as well as this pier fixture------and manually pushed the on button, both fixtures went on for about four seconds and then suddenly both went off. The breaker switch did not trip. I tried it again and the same thing happened. My house was built in the 1950's so there is not a green wire or bare copper copper wire coming into the base of the fixture. The fixture itself did, of course, come with a bare copper wire. When I unwired the new fixture, the front door fixture worked fine as did the timer. I also checked the timer itself to see if it was overloaded, and that's definitely not the problem. I checked the connections in the box. I made sure the terminals outside were clean. If the underground cable was in some way compromised could I expect these symptoms? I've entertained the idea that the new fixture may be broken, but that's really reaching. Also, the mason who worked on the walk was careful, clean and well organized. I'm pretty sure he didn't damage the cable, and the previous fixture in the same place had been working fine. I'm thinking I'm somewhow at fault here! So--------- now what. Thanks alot!!

Old 07-31-02, 07:58 AM
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This does seem puzzling! Here's my one and only thought so far.
You say that these lights are connected to a timer. I am assuming that this is one of those in wall timers that replaces the switch that originally controlled the light. That being said the only thing that I can think of is that it may, in fact, be over loaded! Look at the rating on the timer and see what it is rated for. Some are rated for 300 watts some are rated for 600 and there are even some that I have seen that are only rated for 150 watts Max. Once you have that information you have to look at how many watts you are actually putting on that timer. You make mention that you didn't overload the circuit, how did you come to that conclusion?

One thing that you haven't told us, which could figure in here, is how far that new fixture is from the house and what size wire is run to that fixture. I know this all sounds odd but, I can't come up with any other reason that the addition of the new fixture would cause the timer to stop working in the manual mode. Especially, when you say that this only occurs when you add the pier fixture.

It's possible that when the distance is added as a factor that your additional load will exceed the timers limits! Other than that I am at a loss. One question: Were you able to clearly distinguish which wire was the hot and which wire was the neutral in the cable that you used and are you sure that you terminated them on the correct wires on the fixture.

Some wall timers use the light bulbs themselves as part of the circuit that the timer requires to operate. In essence, the timer seeks it's neutral through the light bulb that it serves.

Hope this at least gives you a starting place.
Old 07-31-02, 02:59 PM
Doug Lon
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Outdoor Wiring in Response


This same cable operated the old fixture which is the same distance as the new fixture. I had previously checked the timer which is rated for 400 watts. The load from the two fixtures doesn't come close to this. The hot and neutral are clearly coded. The new fixture is wired the same way as the old.

If I'm to think strictly in terms of variables that have changed, only one thing has potentially changed and that is the mason had to demolish the old pier and there was digging that he did in the area the cable emerges from the ground. I'm more psychologist (by profession) than electrician, and I'm not comfortable testing volts and what not (unless I could be made to feel more able!!). It just seemed so odd to me that not only did both lights turn on for several seconds and then abruptly go off, but it did this two more times, before I decided it seemed prudent to unwire the new fixture. Could the cable be damaged in such a way to make that happen. This seemed more like the ways the lights would go out if the timer turned them off. I guess I could disconnect the timer and connect a regular switch--- but do I want to that. This is a middle of the run wiring with a 2 gang plate (There's a switch next to the timer that operates another light inside the house). So its a formidable array of connections in there (even though I do believe I know what the basics of why what wires are connected where).

Anyway thank you Sparksone-------------------- Doug
Old 07-31-02, 05:42 PM
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You may want to temporarily replace the timer with a switch to verify that the timer is not the culprit.

When you unwired the new fixture, where did you disconnect it - at the fixture or at the house? If at the house, reconnect it there and disconnect at the fixture - if everything works that rules out most of the possible cable problems.

Did you try hooking up the old fixture again?

Can you give more information on the new fixture, and how it may have differed from the old one?

You don't have a dusk-to-dawn feature (daylight sensor) with this timer that the new fixture could be falsely triggering when it turns on?

Just a few straws to grasp at.
Old 08-01-02, 07:29 AM
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Those are good!! Here may be another good straw to grasp at!!! You may be closer to right than you think about the mason possibly damaging the line. What you describe sounds like it could also be a high impedance type of short. That would explain why it takes about 4 seconds to shut off. The only problem with that theory is that it should trip the breaker.
My only other thought is if this timer has some kind of integral protection to it, the timer itself could be doing the tripping.
If you know where the cable is buried then I would take the time to CAREFULLY dig the cable up, in the same place the mason did, and visually and tactily inspect the cable for any signs of damage. The short that I would think you would be looking for is one where the jacket of the cable would have a slice in it from the shovel but, that slice would not go all the way through the cable severing it.
Short of finding anything there, your only other avenue would be to use an ohmeter and disconnect the light leaving the two wires open and not touching each other and then going into the switch box in the house and locating all of those conductors coming in from that light and checking the resistance of each one against the others. If there is some kind of a short you will find it that way. One of your readings will be significantly different than the others.
Hope this helps some.

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