Help! Light on 3-way switch always has some power.

[barlowc]

I added a light in my basement controlled by a pair of 3-way switches. It's a new circuit. Things are wired as shown in the following diagrams.

The problem I have is that, regardless of the state of the switches, there is always some power to the light. Two of the four up/down switch combinations result in full power. The other two combinations result in a reduced amount (i.e. approximately one-third) of power.

I have quadruple checked the wiring and can't find anything wrong. I've also swapped out each switch one at a time to rule out a faulty switch. I just can't figure it out.

 

[atikovi]

Maybe post here, https://www.doityourself.com/forum/electrical-ac-dc-9/

 

[greenjp]

Actual power as in the lights are on like at full dim, or a stray voltage like you're seeing 10v on the multimeter? If the latter it's pretty typical inductive voltage, miniscule amps behind it. Putting a load on will drop it.

 

[barlowc]

The circuit tester I was using has a small orange light that indicates if there is power. Two of the four up/down switch combinations result in the light being brightly lit. The other two combinations result in it being dimly lit.

I just connected the intended light fixture which is a 4" 9-watt (50-watt equivalent) canless, recessed LED. (Eventually there will be 4 of them strung together in series.) That light either appears full on or full off. So maybe it's what you suggested greenjp?

 

[Touring5]

If the switch(es) are illuminated and/or are electronic, there will be a small leakage and apparent voltage present when "off". I have a " Maestro" dimmer on a 3-way circuit that does this. In fact, the small leakage through the switch will actually cause the led lights to be very dimly lit when off. I think it's referred to as "ghost light".

 

[nomas]

Circuit testers can be deceiving . Buy a multimeter .

 

[ironman_gq]

Hang onto the wire (the insulated part) when you test it, it's pretty common to see voltage on a meter on an otherwise dead line. Something to do with capacitance and induction. Keep in mind that on a 3 way setup there will always be power on one wire in the bundle but it's not uncommon for voltage to magically appear where it shouldn't. You can also grab the neutral wire and check for voltage, touching the wire should dissipate any stray voltage, just make sure to not touch any other wires at the same time or ground yourself as that could cause a shock.