low voltage light control relay, switch loop replacement

Old 02-24-04, 08:37 AM
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low voltage light control relay, switch loop replacement

I have an unsafe three-way lighting circuit which I would like to improve.

The wiring arrangement has the feed going in to the junction box above the light fixture, which then supplies a downstream outlet and a switch loop. The switch loop then provides power to the light fixture.

The switch loop has two three way switches, and looks like a normal three way circuit, no switched neutrals or other such nastiness.

However the wire is clearly undersized, would not meet code at the present time, and was probably not code compliant at the time of the install.

The wire used was some sort of rubber insulated cloth covered wire, and the cable used for the switch loop has two larger and one smaller wire, all covered in an outer cloth or cloth tape covering. The conductors are _stranded_, and look like two 16ga and one 18 ga wire. (possibly 14ga and 16ga). My best guess is that this is some sort of appliance cord.

Additionally, going into the lamp junction box there are only two conductors from the loop, and going into each switch box there are three conductors. This makes it nearly certain that there is a flying splice in the switch loop.

IMHO the only reason that this wiring hasn't started a fire is that the load is fixed and low current (a single 60 or 75W lightbulb)

Clearly I cannot continue to use this wire.

In the ideal case I would use the wire to fish in a new cable, and then simply install a proper three way switch loop.

The problem is that there is a mural on this wall, and thus cutting into the wall is out of the question. If the old cable is not free pulling, I will be stuck either having to use the old cable (in some safe fashion) or using some sort of control.

I would like to know if there are any 'self contained' light control relays which I could use, which would permit me to continue to use the old switch loop wiring, but only carrying control voltages and currents. The wire is not ideal, but I would trust it to carry 12V and 50mA to operate a relay coil. Does anyone have any pointers for a relay that I could mount on or in the lamp junction box, where shorting two control terminals together would activate the relay, but where the control voltages and currents are limited to 'intrinsically safe' values?

Does anyone have other suggestions for replacing the functionality of this switch loop without going into the wall behind the loop?

Old 02-24-04, 09:52 AM
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If you can't fish new wires, one option would be to use and X10-type remote control switch to control the fixture.

Besides X10 there are a few other such systems from companies like Lutron and even Black & Decker.
Old 02-24-04, 09:56 AM
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John Nelson recenty solved a switching-problem for another participant in the Forum by suggestion a "remote-contol" switching-device. Perhaps he will respond------

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