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Author Topic: Rig blows circuit breaker in plug  (Read 6030 times)
N8TI
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Posts: 115




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« on: March 31, 2012, 03:43:05 PM »

Hello everyone. You know those ground interruptible plugs they put in kitchens?  I have my Kenwood TS520 in my kitchen with a temporary antenna on my deck. The xyl was out of town this week, so I played with radio all week.

I ran an extension cord to my shack downstairs where I have 30 amp circuits. So, I have nothing hooked up to the circuit in the kitchen. This circuit in my shack is all by itself, specially installed for ham radio.

However, when I key on CW, I hear a little buzz and I trigger the circuit breaker in the plug. There is nothing connected to that circuit.

Why would keying my radio which is plugged into a separate circuit blow the circuit breaker in the plug?  When I use the toaster, it does not blow, so it is not "weak."

Is there RF feedback going into the wiring?  The wiring on the kitchen circuit is about 3 feet away. I do not have a ground connected to the radio. Probably should try that to a cold water pipe. But, what do you think?

Joe
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N8TI
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Posts: 115




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« Reply #1 on: March 31, 2012, 03:50:15 PM »

Grounding it did not help.

Joe
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KS2G
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Posts: 368




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« Reply #2 on: March 31, 2012, 04:33:54 PM »

It's the RF from your radio "tripping" the GFCI.
Common problem.
Try installing a different brand of GFCI.
That usually cures it.
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WX7G
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Posts: 5920




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« Reply #3 on: March 31, 2012, 05:19:43 PM »

The newer GFI's are more immune to RF. I replaced an RFI prone GFI and it fixed the problem.
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N8TI
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Posts: 115




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« Reply #4 on: April 01, 2012, 07:55:36 AM »

Thanks. It will make the xyl feel better when she gets home.

Joe
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AA4HA
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Posts: 1378




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« Reply #5 on: April 16, 2012, 06:59:17 PM »

If you think of how a GFCI device works then it becomes pretty clear on why they "freak out" around RF. They are trying to detect miniscule amounts of leakage current differences between the neutral and ground wire. Taking one apart that I had physically broken (smashed it between a bookshelf and the outlet box) was enlightening.

You probably could of helped yourself with some ferrite RFI beads on the AC line cord, improved station grounding or some work on your antenna system.

It is a "good" thing that they are so sensitive. I have only had one that was too picky and it was on an appliance that was having problems (washing machine that eventually died, the motor windings were always getting wet from a leaky water pump).

As I can afford it (extra $50-$75 sitting around) I go and replace another breaker in the circuit panel with the ultimate goal of having an all GFCI house. Sometimes on near lightning strikes I will end up with GFCI breakers tripping out (I am ok with that too).

There was a guy in high school who I admired from a distance who died a tragic death by electrocution while working at a restaurant. It is a subject that is a little near to my heart.
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
AA4PB
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Posts: 12685




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« Reply #6 on: April 17, 2012, 05:46:52 AM »

"They are trying to detect miniscule amounts of leakage current differences between the neutral and ground wire"

Actually, they detect differences between the hot and the neurtal currents. If they are the same then there can't possibly be any current leaking to ground anywhere. This way it doesn't matter if the leakage current flows in the grounding wire or some other path such as metal plumbing, concrete floor, etc. I think the max leakage current is 5mA, if I recall correctly.

Also remember that if you somehow get connected between the hot and neutral lines then the GFCI breaker will not protect you because it doesn't cause a current inbalance between hot and neutral connections.
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W9GB
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Posts: 2599




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« Reply #7 on: April 17, 2012, 07:45:57 PM »

Quote
Hello everyone. You know those ground interruptible plugs they put in kitchens?  I have my Kenwood TS520 in my kitchen with a temporary antenna on my deck. The xyl was out of town this week, so I played with radio all week.
Joe-

Your problem is that temporary antenna setup!!  Common-mode RF !
Put a balun, unun or choke balun at that feed point.
I bet the antenna is a vertical ...

Common mode RF can shut down SMPS (switch-mode power supplies),
Effect some GFCI, influence cheap import POTS phones, etc.

w9gb
« Last Edit: April 17, 2012, 07:48:54 PM by W9GB » Logged
N8TI
Member

Posts: 115




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« Reply #8 on: April 18, 2012, 07:52:59 PM »

I moved the rig to my station that has a permanent antenna on my tower and problem is gone. The antenna that was causing problem was about ten feet away from plug causing problem. I had an ugly balun, but rf in shack must have been problem.

Just sort of scary, with the buzz and all.

Joe
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W0FM
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Posts: 2052




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« Reply #9 on: May 04, 2012, 11:03:42 AM »

Hi Joe,

Please note that this comment is meant to be helpful, not critical.  The GFCI is an "outlet" not a plug.  The "plug" is what is on the end of a power cord, etc.  Everyone here figured out what you meant, eventually, but getting the two straight may help if you need assistance on similar issues in the future.  Have fun.

73,
Terry, WØFM
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KA5N
Member

Posts: 4380




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« Reply #10 on: May 05, 2012, 03:10:44 AM »

Motion sensor light switches are also prone to this kind of pickup.  The lights in my bedroom
will turn on when I am on 10 meters and also when a police crusier or city vehicle transmit
near my home.  I have never bothered to try to cure this as it serves as a "narc alarm".
I am still working on my cop car CC award.

Allen
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