[Antennas] RFI and GFI

[Eric Lemmon]

Dave,

You didn't say so, but I assume that your rig is not on the same circuit
as the bathroom; if it were, almost any RF generator would trip the GFI.

Check to see if the bathroom GFI is on a multiwire branch circuit. 
Electricians can, and frequently do, use 14/3 or 12/3 cable to run two
circuits with a common neutral.  The important thing is that the two
"hot" wires must be on opposite sides (phases) of the 120/240 VAC (in
condos, often 120/208 VAC) service.  If this  is the case in your home,
and your rig is sharing a neutral with the bathroom GFI, you will likely
trip the GFI.

The fix that almost always works for me is to run a dedicated 120 V 20 A
circuit from the service panel to the shack.  The antenna tower or mast
should have both an RF ground (your radials) and a safety/lightning
ground per the NEC.  The NEC requires an earth ground (rod) at the mast
or tower, and this ground should be bonded to the service ground.  The
grounding stud on the rig should be connected to the tower ground, to
ensure that the RF and safety grounds are common.

You might also try replacing the GFI that trips with a new one, and not
the cheapest one you can find.  The higher-quality GFI units made these
days have better RF filtering than those made just five years ago.

73, Eric Lemmon WB6FLY

Dave Shrader wrote:

> At or above 500 watts on 40 CW the main bathroom GFI trips! [on dashes
> not dots ...!!].  Obviously, RF on the ground [neutral] wire. The
> individual GFIs in the 2nd bathroom and outdoor shed do not trip.
>