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Author Topic: GFI Brakers not GFI Outlets  (Read 3797 times)
N5WXB
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« on: November 22, 2012, 10:12:03 AM »

Good day to all, I am the maintenance man for a brand new upscale apartment bldg. that my company gave me an apartment.  I am on the 3rd floor of a 5 floor building. I have snaked my coax up to the roof through the dryer vent to a 149 ft Windham that is 15' above the roof.  I am fine using 20m to 160m but if i go to any other I am blowing ALL the GFI Brakers that cover Bedrooms in all the apartments on the 2nd and 3rd floors!  The residents are beginning to get a little upset and I'm afraid that if the owners find out it's me i may have a problem.  Aside from staying off frequencies above 20 is there any other thing I can try?   Trial and error for me means going into or getting permission to go into all 26 units re setting bedroom brakers and just makes these up-scale residents upset resetting clocks and the like.   I am using the Ground in the Bldg. as my common ground but i feel without it would be worse.   It is now code here in Va. that all new construction use these GFI Brakers on bedrooms.  I'm beside myself.....
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AA4PB
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« Reply #1 on: November 22, 2012, 10:23:28 AM »

I'd try a balanced antenna like a dipole with a balun at the center. With an unbalanced antenna you are feeding RF into the ground - the same ground that all the GFI breakers are attached to.
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N5WXB
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« Reply #2 on: November 22, 2012, 10:34:59 AM »

Hey, thanks for the reply, that would leave me worse then where I am, working on only 1 band.....  The windham has a 4/1 Balun on it.  Another note, If it wasn't me popping these brakers I would be riding the Electric company pretty hard to fix their problem as the building was only finished 2 Months ago.  I would not be thinking as a Maintenance person that I was dealing with RF as a culprit....
« Last Edit: November 22, 2012, 10:42:11 AM by N5WXB » Logged
AA4PB
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« Reply #3 on: November 22, 2012, 01:28:35 PM »

Well, you could use a trapped or a fan dipole. If your existing antenna is okay on 20M and below then you could add a trapped 15/10M dipole.

You could also reduce power output when operating 15M or 10M on the existing antenna.  A coaxial trap on the coax before it goes inside the building might also help.
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N5WXB
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« Reply #4 on: November 22, 2012, 02:51:49 PM »

Wow, you reminded me that I have forgotten that I have been operating at 40W since my 1st "on air" at this QTH resulted in the 4th and 5th floors blew their GCFI Breakers when operating above 50W so I set @ 40W to solve that problem but now I'm hitting the 2nd and 3rd floors and already using low output.  Remember again I have little to know room for experiment.  I was thinking of posting a notice for a 3 hour notice of possible outage while "troubleshooting" problem, but if I was unable to find the correct settings in that time i'm screwed to being limited.  Looking for more then just obvious....  I have this 1 time give it a try and whole 46 unit building to figure best outcome.   Thanks for reminding me about the output being @40W. 
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AC4RD
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« Reply #5 on: November 22, 2012, 04:40:05 PM »

Hey, thanks for the reply, that would leave me worse then where I am, working on only 1 band.....  
You need to run coax up to the roof, right?  How about a coax run to the roof, and then a balanced antenna fed with twinlead from an automatic tuner?  I'm using a similar setup a lot of the time (long horizontal run of coax, not vertical, but it's the same setup) and it works quite well.  This would let you use your balanced wire antenna on any band higher than the overall length (i.e, 66' on each side would be fine for 80meters and above.)  Just a thought.  You WILL notice much less RFI with a balanced antenna than with a Windom, I'm pretty sure. That might solve your problems.  GL!
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WX7G
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« Reply #6 on: November 23, 2012, 05:46:39 AM »

The 4:1 balun may or may not have sufficient common-mode impedance to do the job. You could add a 1:1 current balun after the 4:1 balun. A Balun Designs #1115 might do the job. With the Windom you are fighting an uphill battle, so to speak.

But if you want to fix this in one shot I recommend a trap dipole as AA4PB says. Add a Balun Designs #1115 at the feedpoint.
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W6GX
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« Reply #7 on: November 24, 2012, 10:50:51 PM »

I'm 99.9% sure the issue is not the balun or the antenna.  The issue is with the breakers.  The breakers that you are tripping are the newer AFCI type as required by code on all new constructions.  Here's a link to the AFCI primer:  http://circuitbreakerstips.com/category/afci-breaker/.  These breakers are very sensitive to RF.  The RF generated by your antenna is strong enough to trip these newer breakers, regardless whether you have common mode current or not.  I live in a new home and I'm seeing the same problem.  When I first got on the air all the AFCI breakers would trip the instant I started transmitting on certain bands.  After some experimentation with different types of AFCI breakers I found one that wouldn't trip.  I run up to 1500 watts and so far no issues.  Replacing all of the AFCI breakers on the 2nd and 3rd levels will be expensive and time consuming.  Obviously using the older non-AFCI breakers will be less expensive but you would be violating the electrical code.  If you decide to not replace the breakers then I would experiment and find a power level threshold that wouldn't trip the breakers.  I didn't have any issues running barefoot (100w) before I changed out the 'non-ham friendly' breakers.  Good luck.

73,
Jonathan W6GX
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WB4BYQ
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« Reply #8 on: November 25, 2012, 06:25:50 AM »

having just built a new home in less than two years, there are square d arc fault breakers in the panel.  i have not removed one yet, for the part number, but running about 1kw no problems so far.  maybe the distance to the ground is a problem since the breaker has a second ground on the second and third story.  so far no problems with the GFI's at the outlets. 

richard

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AA4PB
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« Reply #9 on: November 25, 2012, 11:30:35 AM »

The AFCI breakers actually contain a small microprocessor that monitors the load current waveform. I expect that not only are they sensitive to RF being picked up on the wiring, but they may also be a source of RFI to our receivers. Antenna separation is likely the best solution whenever possible.

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N7EKU
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« Reply #10 on: November 25, 2012, 11:45:00 PM »

Holy Moly,

You sound more like an "anti-maintenance" man yow!  Wink

Some have had some luck with the MFJ artificial ground, but I think you need to give up trying stop-gap measures with an unbalanced antenna, like quite a few others have suggested.

Although I wonder about the life-span of coax in a dry vent  Huh, you could just run another one up and install a trapped or fan dipole for the higher frequency bands that you want.  That would you give you much less loss in your coax run and should be a much more enjoyable antenna for you and the tenants.

Whatever you do, it would be a very good idea to install current chokes at the feedpoint before the coax runs into the building to block rf from running down the outside of your coax.

Any chance of getting a real ground?  Maybe you can convince the owners of the advantages of a good earth grounding system for the building against lightning strikes and make sure the line runs right by your apartment  Cheesy

You're kind of stuck in a hard spot... top floor and you could run a balanced line out the window (300ohm twin lead would be pretty stealth since it looks kind of like coax), bottom floor you could get a real ground easily.   Maybe you can switch apartments?

Good luck and keep asking questions.  Someone may have a charger for their oxygen, pacemaker or insulin pump on one of those outlets some day and that wouldn't be a good thing to have on your conscience if there was a problem due to that  Shocked

73,

Mark.

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NO9E
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Posts: 439




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« Reply #11 on: November 26, 2012, 09:09:17 AM »

Since you are tripping breakers at 2nd and 3rd floor and the antenna is over the 5th floor, a radiation at your floor and not the top is causing a problem. Most likely the house wiring is part of the antenna. Then the RF connection to house wiring needs to be stopped. 

Several solutions.

1. 1:1 balun on top.
2. 1:1 balun at the radio.
3. Radio operated from battery (if radio not computer controlled)
4. Power cord to PS wrapped many times around a ferrite rod.
5. 1:1 transformer wound on iron core.

In the past, solution 4 reduced TVI in my apartment bldg dramatically. Solution 5 would break common currents at cost of increased SWR on some bands. Usually not important if you use antenna tuner.

Ignacy, NO9E   
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