Timers without neutral

[greg123]

This has me puzzled - its also late here, so that might be the problem.

How does a timer like this http://www.smarthome.com/images/4253adgm.gif work - without a neutral connected to the timer. As in, when the light is off - the timer is still on, without a compleated circuit. Or is the power to the light very small.

Thanks :p

[L. Daniel Rosa]

That's entirely possible. It's also bad form to have a load never completely disconnected. it's also possible that the timer is connected between line and ground- also bad form and incompatible with GFCI.

[dacflyer]

the lamp provides the neutral to the timer..and there is a small ammount of current being sampled
many of Plug-n-Power / X10 moduals work this way for the wall switches and dimmers etc.

[greg123]

Thats what I thought - we actually disconnected the ground and it still worked. So, it didn't make sense immediatly that it could still have power with the lamp off - since there is no neutral in the timer.

[Gorgon]

Just measure the voltage drop over the timercircuit when the lamp is on. You will then see if the timer 'steals' a small amount of the voltage. When the lamp is off, it will still be a small current through it, to supply the timer circuit.

TOK