Just installed a replacement dimmer switch that exhibits the same strange behavior as the previous one.
It's on a circuit that's wired correctly. I have a dedicated outlet running a string of low-voltage halogen lights through a transformer. When I installed the first dimmer, it worked fine. When I checked it with my handy-dandy circuit checker (you know, the type with the 3 leds), it indicated the circuit was OK with the power applied. BUT: when the dimmer was switched off, the tester indicated a fault ("open neutral", it said).
So I replaced the dimmer temporarily with a single-pole switch; circuit acted normally with power on and off.
Then I replaced the dimmer (it's a Lutron "decora"-style with the big rocker switch on front and a little slider doohickey). Guess what? Same deal; tester says "OK" when on but "open neutral" when off.
What gives? All I can think is that the dimmer is drawing just enough current when in the "off" position to spook the tester. (Yeah, I know those types of testers aren't 100% conclusive, but shoot, it's better than sticking your fingers on the damn wires.) Why this would be the case, I have no idea.
Although, I just realized: the dimmer packaging says "locator light" on it; is there a dim light on this that is drawing this current? (I'm not at my client's site right now.)
D "puzzled" N