Consider a light with two duplex switches. The switches work as I can turn light on/off from either switch. However, I'm not getting any voltage reading on my meter. The meter does work as I can get a reading on another circuit. This is existing wiring and I don't know the wiring plan. I want to know where the fixture is in relation, wiring-wise, to the switches (before, between, after). Where should I place my meter leads to correctly measure voltage in duplex switches?
Electrical – How to measure voltage in a duplex (three-way) wired switch
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Related Solutions
If one switch is overriding the other in a three-way circuit, that usually means one of the switches has been hooked up incorrectly. If you get the common and one of the travellers exchanged, you will see exactly this behavior.
Double-check each switch to make sure you know which contacts are the common and the two selectable terminals, and double-check that the latter two are the ones hooked to the travellers.
(This is not an uncommon error.)
I believe this is what you are requesting: the new light must always be off when the original light is off but can optionally be turned on while the original light is on.
To accomplish this you can connect the new light in parallel with the original light, but with a switch on the hot leg, like this:
Or use a new light that has a built-in pull-chain, which is a switch that will accomplish the same thing.
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Best Answer
What you are looking for is called "Three way switches", although it will only be two switch locations. There are several wiring schemes that can be used, depending upon where the main power is derived from, switch box or light fixture. This link explains 8 different scenarios.
One box will have the feed voltage, 120 volts ac. It can be in either of the switch boxes or the light fixture box. Any readings across the switch terminals would depend on the switch settings and that would require a light bulb installed that would complete the circuit.