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stephenbishop 03-09-2012 10:50 AM

confusion with track light
I'm trying to fix a problem with a track light installment over the a bar I've just put in. I've done it before. never had issues. but this particular problem is driving me nuts. It just defies logic. The electrician who actually installed the associated dimmer switches with this dining room area was called as it seems it may be a flaw with his wiring, but he's blown us off and I have to try and solve this myself.

This is how it's all set up. I've been rehabbing our home from top to bottom, and converted our old kitchen into a dining area. Within this dining area are four sets of lights, all controlled from one box containing four dimmer switches. I set up all the new wiring and installation of the lights in the ceiling, and we paid an electrician to come in, check everything out, set up the multiple switches, and connect it all to the board. It's all new copper wiring from beginning to end, as I didn't want to connect or splice in to the old aluminum wiring that was in place. All the new wiring and lights are on a dedicated 15 amp breaker. Three of the sets of lights were set up to be available from the day the electrician came around. The fourth, for the track light over the bar, was left hanging from the ceiling capped off and with the switch off, as I still had work to do installing an overhead wine rack, under which the track was going to be set.

Two days ago I finally got around to putting the track up, but after setting it in place and connecting the power up the lights wouldn't work. I took the lights out to our kitchen, where I installed another track light system some time ago, plugged one of the lights in, and it worked just fine. I then went back to the bar area and used a spare track, then a spare connector, to see if I could isolate the fault, yet neither of the items provided a solution. Now here's the weird bit - every time I tried checking the system out, I'd get 120 volts showing from the wiring and from the track when I'd test with the multimeter. But the second I'd put a light into the track, the multimeter would drop to zero on the voltage reading on either the wiring or the track. Take the light fixture back out, and the voltage would pop back up. Inserting the light was thus completing some kind of odd loop. It wasn't just one light - I double checked by grabbing working lights from the kitchen track and inserting them into the other track - the same problem would pop up. Finally, having come to the conclusion that there was nothing wrong with the track at all, I took the whole assembly over to a nearby wall outlet, used some spare electric cable to connect up to the appropriate slots - presto, the light came on! I even double checked all this by grabbing another light fixture destined for our bathroom, and tried connecting it to the wiring over the bar. Nothing. Yet as with the track light, the minute I took it over to the wall outlet and connected it, the light worked.

So everything logically points to the fact it has to be something to do with this individual circuit, right, because a) the light fixtures work when plugged into another circuit and b) the other three dimmers and lights hooked up in the same box work fine and draw power from the same wire cable/breaker combination. The only things left that I can think of is that the electrician has either wired the dimmer switch up incorrectly or that there's some kind of flaw inside the switch itself. Does this make sense?

A friend also told me to double-check to make sure that the black wire feeding power to the light was indeed the hot wire, and it is. If I touch it with the black test lead from the multimeter and put the red one to the neutral I show 120 volts. If I keep the black test lead on the black wire and put the red test lead to the ground - I also show 120 volts.

A final point. I know I'm not overloading the circuit - not even close. With all four dimmers maxed and every light on - including the test light on the track - I'd only be drawing 8 amps on a 15 amp breaker, besides which I'm only using one set of lights while I'm working on this problem anyway. This is a dedicated circuit, so there's no additional power being drawn away by something else.

So how am I getting 120 volts from this wiring, according to my multimeter, yet it won't light up ANYTHING and keeps giving off the indication that some kind of loop or short is being created every time I actually plug a light into the track? It's got me totally stumped.

Anyone have any ideas?

hawkeye11 03-09-2012 11:05 AM


Originally Posted by stephenbishop (Post 874082)
The electrician who actually installed the associated dimmer switches with this dining room area was called as it seems it may be a flaw with his wiring, but he's blown us off

haha, that wasn't very understanding of your electrician. Anyways, how many wires do you have at your track light? Just a black and white? (pictures of this and the switches may help considerably)

PaliBob 03-09-2012 11:13 AM


...getting 120 volts... yet it won't light up?....
You may be missing a return path, i.e. the neutral.

jbfan 03-09-2012 11:20 AM

I guessing a loose neutral.
What wires are in the ceiling?

stephenbishop 03-09-2012 12:30 PM

Okay, I don't know if this helps, but I pulled the dimmer out of the box so I could have a look at how the wires are hooked up, and this is what i found -

There are four wires coming out of the dimmer at the back. A black one and a red one in the left corner, and another red one paired with the green ground wire on the right corner. The red wire on the left is not connected to anything - it's just capped off. The black wire is connected to another black wire. The red wire next to the ground is connected to a black wire. And finally, the ground is connected to other grounds. Note that there are four dimmers in the box, so I'm guessing the connections go to the neighboring dimmer or to a common connection for all of them. I could pull them all out to check, but it would be a pain at this stage.

Next came some testing -

Step 1 - I took the wire nuts off at the back of the dimmer, making sure the joined wires stayed together, and touched some wires running from a light fixture to the now bare wires at the back of the dimmer. Nothing, no light at all.

Step 2 - With the dimmer in the off position, I used my multimeter to check the voltage on the bare wires behind the dimmer. I got a reading of 25 volts (???!!!) regardless of whether I swapped the test leads around to touch the hot wire and the neutral. The actual wiring above the bar, where the track light is supposed to be connected, showed no voltage at all, which is what I would have expected. What I didn't expect was 25 volts showing at the back - where's the missing 95 volts gone to?

Step 3 - With the dimmer in the on position, the multimeter showed zip voltage at the dimmer (regardless of which way I tested) but 120 volts at the bare wires above. Shouldn't I be reading 120 volts all along the line?

Note that all of this was done without any lights attached. I was trying to see what was going on with the wiring independent of the lights.

Now if any of you can figure this out, you're better men then me, Gunga Din! I'm no expert obviously, but all of this just seems very odd. By and large wiring seems fairly logical and I usually don't have much trouble figuring out the basic stuff - and this stuff should be basic.

I have a spare dimmer, and my next step may be to swap it in, even though it will mean having to monkey round with the other dimmers as well to make the connections. I'm hoping one of you might have an answer before I have to go that route. That's of course if my wife doesn't come home and find me dangling from the ceiling with a noose round my neck out of sheer frustration!

As for the questions on the wires, no, I have the ground wire available to the ceiling location for the track and have done the tests mentioned before with it connected and without - just to be sure I didn't have some kind of grounding issue.

HouseHelper 03-09-2012 12:42 PM

Sounds like a loose connection. The connection is good enough to get a voltage measurement, but not good enough to pass current. If power is fed to the switch box, then suspect the neutral (white) connection because it will be several wires wirenutted together... one may have slipped out just enough to make a poor connection.

stephenbishop 03-09-2012 01:42 PM

Okay, solved it. Problem was the dimmer switch. Why do things have to be so difficult? A half hour job that takes 6 - 8 of head scratching to solve. On to the next problem in the home rehab!

Thanks for the feedback.

PaliBob 03-10-2012 01:37 PM


Originally Posted by stephenbishop (Post 874199)
….solved it….. Why do things have to be so difficult?…..

Partly because of making a wrong assumption.
In Post #1 you said “…getting 120 volts…..yet it won’t light up?....”
You read that on your DVM right? And DVM’s don’t lie right? Well DVM’s do lie and because of their high input impedance they are prone to all kinds of ‘Ghost’ voltage readings.

If your DVM leads had been in parallel with a lamp load you would not have read 120V.
To eliminate erroneous Ghost voltage reading you can make sure the voltage source is simultaneously connected to a lamp load or use a Wiggy type AC Tester. They have a much lower input impedance to activate their internal solenoid which vibrates to give an audible and visual signal.

The name Wiggy is registered to Klein Tools but is more correctly called a Solenoid Voltage Tester also made by others e.g. Gardner Bender. They work on the same principle as the Wiggy but are usually cheaper because they don’t have the caveat of the Wiggy name.

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