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#66694 06/14/06 08:21 PM
Joined: Mar 2003
Posts: 97
D
Member
A coworker showed me this today.

There was a GFCI in a bathroom and when he keyed his radio it tripped the GFCI. He reset it and did it again.

Nothing plugged into the GFCI.

This is a new one on me.

Can anyone explain this?

Thanks

#66695 06/14/06 08:33 PM
Joined: Sep 2001
Posts: 806
N
Member
The RF signal from the transmitter is getting picked up by the wiring, and is being interpreted by the GFCI as a current imbalance.

A different make of GFCI might fix the problem. El Cheapo GFCIs often omit "needless" filtering components like bypass capacitors. RF pickup can be a problem with cheap residential wiring materials (romex and plastic boxes), which provide no RF shielding compared to AC/MC cable or conduit and metal boxes.

#66696 06/14/06 08:33 PM
Joined: Jul 2002
Posts: 8,432
Likes: 3
Member
It's caused by the RF currents from the 2-way radio transmitter.
It induces a current in the GFCI sensor coil, tripping the internal relay.

{Oops, we must have posted at the same time Kenny} [Linked Image]

[This message has been edited by Trumpy (edited 06-14-2006).]

#66697 06/14/06 09:10 PM
Joined: Dec 2002
Posts: 228
J
Member
In the town I am a firefighter in we had the same problem in a new apartment complex that was being built, but when we keyed up on one channel the gfi would pop and let its smoke out. It then was dead, could not be reset. The GC ended up replacing most of the gfci's in the complex.

#66698 06/15/06 01:25 AM
Joined: May 2003
Posts: 2,876
E
e57 Offline
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Imagine what it does when you talk into it....


Mark Heller
"Well - I oughta....." -Jackie Gleason
#66699 06/15/06 08:21 AM
Joined: Jun 2001
Posts: 161
M
Member
We had a system setup to feed power to within the 12' vertical area above a pool so we installed a bunch of GFCI's in a Hoffman box. Our radios would trip all at once. We traded out one of the boxes for a RFI shielded box and they still tripped, presumably from the unshielded wiring that left the box. Our fix was to post a sign not to key radio within 5' of the box.

The guys were wondering if the "radio key" method meets the OSHA GFCI testing requirements. It was easier than testing hundreds of GFCI's each month... (Still had them test by the pushbutton)


Mike Wescoatt
#66700 06/15/06 04:07 PM
Joined: Feb 2005
Posts: 361
C
Member
[quote]The guys were wondering if the "radio key" method meets the OSHA GFCI testing requirements. It was easier than testing hundreds of GFCI's each month... (Still had them test by the pushbutton)[/quote

...but then who resets them all?

[Linked Image]


~~ CELTIC ~~
...-= NJ =-...
#66701 06/15/06 05:30 PM
Joined: May 2002
Posts: 1,716
R
Member
If only a device was on the market that when keyed would kill all cell phones in a 1000 sq ft area.

I would buy one. [Linked Image]

Roger

#66702 06/15/06 06:34 PM
Joined: Jan 2006
Posts: 558
R
Member
Try keying your radio beside your computer monitor or near a regular am / fm radio and see what it does mine throws the screen all crazy and maked the radio emit some funny sounds... I am going to try keying up near a GFI just for " Ha Ha's" amd see what happens...

Roger: if such a device were availible ( or buildable) you would see me with one too!

A.D

#66703 06/15/06 06:47 PM
Joined: May 2003
Posts: 2,876
E
e57 Offline
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Gent's they are available, and were slated to be installed in movie theaters until the lawyers of the phone companies got involved. They are currently in use in Iraq..... (To thwart remote bombs)
http://www.cellantenna.com/CJAM/cjam_1000.htm


Mark Heller
"Well - I oughta....." -Jackie Gleason
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