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#21395 - 02/02/03 01:25 PM two way radio and gfi
rpny11080 Offline
Junior Member

Registered: 02/02/03
Posts: 7
While I was using my two way radio the other day I leaned on the counter in my kitchen. There is a gfi outlet within a foot of where the radio was. When I pressed talk on the radio, the gfi tripped. So, I reset it and tried it again. It tripped again. What could cause this?

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#21396 - 02/02/03 01:44 PM Re: two way radio and gfi
maintenanceguy Offline

Registered: 12/02/01
Posts: 303
Loc: Southern NJ, USA
Pretty cool. Maybe you just invented a new GFI tester.

The GFI senses a current imbalance between the hot an neutral wires by measuring any magnetic energy radiating from the wires. If everything's ok, the magnetic field from one wire cancels the field from the other so there is no measurable magnetic field.

I'll bet your transmitter puts out strong enough electromagnetic radiation to be sensed by the GFI.

I'm definately going to try this. What type of radio and what channel were you on?

#21397 - 02/02/03 01:53 PM Re: two way radio and gfi
rpny11080 Offline
Junior Member

Registered: 02/02/03
Posts: 7
I was using a cobra frs radio on channel 12.

#21398 - 02/02/03 02:09 PM Re: two way radio and gfi
Electric Eagle Offline

Registered: 04/20/02
Posts: 928
Loc: Alpharetta, GA
We use Nextel radio's/cell phones and have had similar experiences. With a panel cover off, holding the phone near the panel and pressing the radio button caused every GFI breaker in the panel to trip.

#21399 - 02/02/03 02:11 PM Re: two way radio and gfi
iwire Offline

Registered: 01/05/03
Posts: 4343
Loc: North Attleboro, MA USA
I know you need to be careful with jobsite radios near electronics, I was standing in front of a Energy Management Panel that had LEDs that would blink to let you know the LAN connection was working, that is until I keyed my radio and all lights stopped.
Bob Badger
Construction & Maintenance Electrician

#21400 - 02/02/03 04:16 PM Re: two way radio and gfi
rpny11080 Offline
Junior Member

Registered: 02/02/03
Posts: 7
The radio also makes tv screens get fuzzy, computer screens wavy, and speakers buzz when it is in close proximity to these things. I doubt that it is a good idea to bring any kind of two way transmitter near expensive electronics.

#21401 - 02/02/03 05:45 PM Re: two way radio and gfi
Mike Wescoatt Offline

Registered: 06/17/01
Posts: 164
Loc: Cedar City, Utah
On all of our GFCI panels we have signs posted that say "Do Not Key Radio Within 5 Feet Of This Panel". One of them we've been having too many trips because of radios so we're going to put it in a RFI shielded enclosure...
Mike Wescoatt

#21402 - 02/02/03 11:37 PM Re: two way radio and gfi
ThinkGood Offline

Registered: 08/07/02
Posts: 1084
Loc: Milwaukee, WI
Wireless phones are generally banned in hospitals--lots of sensitive monitoring equipment (and lives depending on that equipment) around.

The police radios in Philadelphia, PA set off some car alarms as officers drive past while transmitting

Radios and ordnance don't always go together so well, either.

#21403 - 02/08/03 12:42 PM Re: two way radio and gfi
JCooper Offline

Registered: 12/30/02
Posts: 229
Loc: Kendall Park, NJ USA
The fire department I was on had the same problem with GFI's but with one twist, some of them would actually catch fire and/or smoke. I will have to see if I can find more info but it was a specific manufacturer and batch. It happened in about five or six brand new apartments, all in the same complex and it would only react to one frequency.

#21404 - 02/08/03 08:34 PM Re: two way radio and gfi
Scott35 Offline

Broom Pusher and

Registered: 10/19/00
Posts: 2724
Loc: Anaheim, CA. USA
Never noticed any GFCI tripping from Radio transmission - but did notice other stuff acting wierd!

When doing site surveys, our two-way FM Radios would cause Lexmark Imapct Printers to do a "Carrage Return" (run to end of line, then line up on next line).
This would occur if radio transmissions were done within 5 feet of the Printer.
Distortion on SVGA Monitors would occur within the same proximity.

As for the Nextel Cell Phones, My i1000 plus will cause interference on many different things - in either the "Direct Connect" radio mode, or in the normal "Phone" mode.

If the unit is within 5 feet of my "Workstation with Audio", you can hear all kinds of pulsed noise.
Pulses of various length occur every few minutes (when there is any refresh of location or such), and just prior to a call coming in, there will be a pulse train of like 10 pulses just before the ringer starts, or the radio alert starts.

Pulses can be seen flying across Monitors also.

Using either function while a VHS tape is playing - and within 10 feet of the VCR, will cause tracking errors and blows out the tape speed tracking functions (SLP slips to SP for about 100 ms).
This also appears to distort the CRT with pulsed interference (when no tape is played).

So far, no other cellular units have caused this interference (other than Motorola / Nextel). Our friends' Nokia Phones have little - if no interference, as compared to the Nextel / Motorola units.

Knowing this - and the past experiences with the Lexmark Printers, I keep away from IT equipment when using the cell phone / radio, and with the two-way radios.

Scott35 S.E.T.
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

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