The case of the back fed light circuit.

[aftershock]

I tend to pride myself on my residental troubleshooting skills.
I guess though, we all have our bad days.
Scenerio:
Customer has a problem with a light circuit blowing fuses. On that same note, the lights on this circuit will cycle on and off in a random pattern. According to the customer, this has just started happening, and he has not had anyone touch the electrical system in this house for atleast 1 yr.

First thing I find out is, this circuit is being back fed somehow from a receptical circuit. I find which circuit it is, but, after 2 hours and inspection of several openings, I am still scratchng my head. It is not a direct back feed though. The lights cycle on and off.

To make a long story short, I find out that that someone had installed a photocell for some outside lights in a JB with both the receptacle circuit and the light circuit in it. The hot for the receptacle circuit along with some switchlegs for some outside fixtures were tied into the switchleg from the photocell, and a switchleg from the light circuit was tied into the line side of the photocell.

Now, if no one has touched this electrical system for about a year, how is this problem just now starting to happen? :shock:

 

[ramdiesel3500]

Was that customer Tim Taylor???

 

[roger]

Years ago I worked in Fl and the company I worked for received a call from a customer after we had installed a dryer receptacle in a utility / mud room saying that the exterior light outside of this room quit working after the installation.

I happen to be the person available at the time to go check it out.

This house was only about three years old and there was a switch at the exterior door.

When I arrived the owner proceeded to tell me that the electrician should have made sure everything was in working order when he left. (even though the light and it's circuitry had not been touched)

He was adamant that the light had always worked up until now.

After going through some trouble shooting I find no box or wire to the fixture, just a fixture screwed to the wall, the switch had a feed cable capped off in the box but no cable leaving.

The original contractor probably missed it on the RI and simply put it up to get the final.

Since the particular area of FL did and still finals with out power, it was never caught.

It was funny to hear this owner back track and tell me that he was not really sure it had been working but his wife had told him it did.

It was obvious it had never worked and he thought this would be a good opportunity to get it repaired at no expense to himself.


Roger

 

[sparky_magoo]

Are these can lights by any chance? I was on a call last week where the lights would go off for no apparent reason. The HO installed over sized incandesant bulbs in the can lights. The thermal protectors were opening up. He was convinced that he had "gremlins" in his wiring. He had a hard time believing the wrong bulbs were causing the cans to die. Could you have a simalar situation?

 

[aftershock]

These were surface mount overhead fixtures. The photocell in my opinion was cycling on and off due to the fact that it had a hot from one leg of the panel switching a hot from the other leg of the panel through the photocell thus blowing the 15 amp fuse for the light circuit as well ad backfeeding this same circuit.

 

[aftershock]

Are these can lights by any chance? I was on a call last week where the lights would go off for no apparent reason. The HO installed over sized incandesant bulbs in the can lights. The thermal protectors were opening up. He was convinced that he had "gremlins" in his wiring. He had a hard time believing the wrong bulbs were causing the cans to die. Could you have a simalar situation?

Oh, and I have ran across things such as this. I always tell the GC to keep the insulation away from the cans, but Im always back within 6 months because the customer claims the lights are blinking on and off. I end up crawling in the attic and moving the insulation away from the cans myself.
Time is money.

 

[Jim W in Tampa]

Are these can lights by any chance? I was on a call last week where the lights would go off for no apparent reason. The HO installed over sized incandesant bulbs in the can lights. The thermal protectors were opening up. He was convinced that he had "gremlins" in his wiring. He had a hard time believing the wrong bulbs were causing the cans to die. Could you have a simalar situation?

Oh, and I have ran across things such as this. I always tell the GC to keep the insulation away from the cans, but Im always back within 6 months because the customer claims the lights are blinking on and off. I end up crawling in the attic and moving the insulation away from the cans myself.
Time is money.

You will keep doing this too untill you tell him to get the insulation man back to fix it and hand him a bill for you trip.As long as you fix it for free they don't have a problem.Same applies to covered up outlets.