Re: Capacitor to bypass GFI outlet?

[Art Todesco <actodesco@xxxxxxxxx>]

Dennis Brothers wrote:
> "Chris Shearer Cooper" <chrisnews@xxxxxxx> wrote in message
> news:11rdc4ulchilk45@xxxxxxxxxxxxxxxxxxxxx
>
>>The official word from X10 Customer Support is that one way to get the
>>X-10 signals to hop from one phase to another is by "installing a 0.1
>>microfarad, 600VDC capacitor across the two phases in the panel, i.e. by
>>connecting the capacitor across any 220V breaker."
>>
>>Can a similar trick be used to get the signal across a GFI outlet?  That
>>is, what would happen if I attached a 0.1 uF 600V cap from the line to the
>>load?
>>Would the X-10 signal get through?
>>Would it affect the ability of the GFI outlet to detect ground faults?
>
>
> The reactance of the cap is 1 / (2 * Pi * f * C), or roughly 1 / (400 * C)
> at 60 Hz, so it has a reactance of approximately 25K ohms.  If you assume
> the current sense circuit in the GFCI drops one volt (I have no idea how
> good an assumption this is, but you could measure it), the cap would put 40
> microamps of unbalanced current into the load circuit (or looked at another
> way, it would "steal" 40 uA from the hot-side current sensor).  Dunno if
> that's enought to trip the interrupter, but it's a pretty easy experiment to
> try.
>
> I haven't really looked at GFCIs, but isn't it a four-terminal device? I
> would guess so, since it needs to monitor current on the neutral as well as
> the hot side.  If that's the case, put an identical cap across the neutral
> side as well, and things will be back in balance.
>
>     - Dennis Brothers
>
But, what if you use 2 capacitors, one
on hot side (hot in to hot out) and one
on the neutral side, that should keep
the balance.  More guessing here.