Re: Ground Fault Interupters and RFI filters

To: tesla-at-pupman-dot-com
Subject: Re: Ground Fault Interupters and RFI filters
From: Tesla List <mod1-at-pupman-dot-com>
Date: Mon, 29 Sep 1997 21:34:33 -0600 (MDT)
Approved: mod1-at-poodle.pupman-dot-com

---------- Forwarded message ----------
Date: Sun, 28 Sep 1997 23:36:46 -0700
From: Jim Lux <jimlux-at-earthlink-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Ground Fault Interupters and RFI filters 

Your filters probably have enough leakage current to trip the GFI.  The GFI
essentially works by measuring the differential current between the two
power legs. If it is different by more than 5 mA (or so), it trips, on the
assumption that the current is going through a victim to ground. Your EMI
filter probably has one or more capacitors between the power legs and
ground. Some small current flows through those caps (although it doesn't
actually dissipate any power, because it is out of phase with the voltage).
And, more current flows through the cap between Hot and Ground than through
the one between Neutral and Ground (because the voltage is higher). It
wouldn't take much to get 5 mA difference here => X = 115Volts/.005 Amps =
23Kohms or around .1 uF at 60 Hz.