Electrical in Old House for Low Voltage Fixture

[6zbeast]

I was hoping somebody could help. I have installed a low voltage fixture in my hallway and I can't seem to get it to work. The house is old, and the wiring is always a surprise. Many light fixtures, including this one, have voltage in the box even when the switch is turned off (learned this the hard way with the first light I replaced in the house). Seems like the power runs through the fixture down to the swich, instead of the reverse. I don' t know if this would make a low voltage light not work. Maybe the transformer is just defective. When I turn it on, I can barely hear the transformer making a slight buzz sound, but the lights don't light up. I also thought it might be the track, but I've inspected it and it seems okay. I've even tried reverse wiring it, still no luck.

Any ideas?

[RBM]

With the switch "on", you have to test the terminals of the track to see if you have 120 volts. If you do, the issue is with the transformer or fixture, if not, it would be an open circuit, possibly at the switch

[Joseph Meehan]

That wiring is not unusual. It is proper to do it either way.

Someone needs to measure the voltage at the transformer (voltage in and voltage out). Remember that using a digital meter can result in measuring AC voltages that are really not there. For this kind of work a older analog meter is better. The voltage has to be measured at each connection until you find one that is dead.

I would have to guess that if the transformer is buzzing, even a little, it is getting voltage. Have you checked the bulb(s)?

[6zbeast via HomeKB.com]

[6zbeast via HomeKB.com]

[RBM]

A transformer will change the voltage to either 12 or 24 volts depending upon fixture. A rectifier would convert it from AC to DC, but I don't believe any low voltage fixtures need DC

[RBM]

I think you misunderstood him. He's got a switched neutral, which is not proper and dangerous

[6zbeast via HomeKB.com]

[Joseph Meehan]

I must of misread. A switched neutral would be very bad. However I can't see where he said that. If you mean "Many light fixtures, including this one, have voltage in the box even when the switch is turned off" that would not mean a switched neutral, it could mean the power is supplied to the box at the light and a separate run is made from there to the switch.

[Joseph Meehan]

Go ahead and look for 120V it is likely to be something like 12V but start large and then move down.

[6zbeast via HomeKB.com]

Will do. Thanks SOOOO much for your help!

Joseph Meehan wrote:

[Joseph Meehan]

That should not be if it were properly wired and measured. However, as I recall a white wire may be use between the fixture and a switch, but I believe it should be one the switched side of the switch (it should not be hot when the switch was off) and I believe it also is suppose to be marked at each end. I would have to look it up if I were to need to wire a switch like this.

[6zbeast via HomeKB.com]

[Mark Lloyd]

I've heard people say 110, 115, 117, 118, 120, and 125. The actual voltage should be in that range. I measure almost exactly 120VAC here.

Older people are more likely to say 110.

A transformer requires AC, and can change the voltage. It does not convert it to DC. That requires additional circuitry. That is unlikely to be there, since most lights (other than LEDs) will work with AC.

12VAC seems common, but I haven't looked at that many. The LV system I have is 12VAC. Some may use 24VAC.

[Mark Lloyd]

A high impedance source. The voltage is really there, but the source has a VERY low load capacity.

[Mark Lloyd]

Try the 300VAC range. If it shows a low reading, reduce the range until the pointer reads over 1/3 scale.

[Mark Lloyd]

Somehow, I get the idea that the switch is connected to the correct (black) wire, but the connections to the source are wrong, making the white wire hot.

[Mark Lloyd]

White is used between the power source and the switch (always hot). Black is used from the switch, probably so you get the correct colors at the fixture.

I'd rather have all the wires in the switch box, rather than a switch loop. It's more versatile.

It should. I expect a lot to not be marked. I've seen a lot in this house (built around 1969). None were marked. (They also used 10/2 Romex for the 240V circuits, and didn't mark the white as red).

[Mark Lloyd]

It could. Much of my house is wired that way. Romex from the breaker panel is wired to a node near the ceiling light. Cables from the switch and all the receptacles in that room connect to that. You see 2 junctions with a lot of wires in them. One is a bunch of white wires (including a wire to the light). The other is a bunch of black with one white. That white wire is the one going to the light switch.

The "hot" node is not connected directly to the light. Doing so would bypass the switch and keep the light on all the time.

[Joseph Meehan]

..

True. Voltage but almost zero current potential.