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uchesteve
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Join Date: Jul 2010
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Ground Fault on Fire Alarm Panel

10/20/2010 9:58 AM

Hi All, I am working on a Fire Alarm Panel Bosch. 1 fault that refuse to go away is: "ground GROU 01." I disconnected the screen and tested for short circuit between loop wire and ground but there was non. Also, I removed each loop to see which loop is having fault, but does not seem to be from the loop. Meanwhile, I noticed there is complete short circuit between all 0V terminals and ground. I believe this is unusual. I therefore suspect the Power Supply is faulty. Please if anybody has any suggestion or idea that can assist me solve this problem, I will appreciate it. Thanks.
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Doorman
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#1

Re: Ground Fault on Fire Alarm Panel

10/20/2010 10:04 AM

What does the documentation have to say about fault indication "ground GROU 01"?

When you removed a loop, did you relace with a jumper? I assume supervised loops.

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uchesteve
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#2
In reply to #1

Re: Ground Fault on Fire Alarm Panel

10/20/2010 10:36 AM

The documentation is silent about it. Meanwhile, it is not supervised loop. When I removed the loop, it only indicates fault due to the removed loop. the faults clear when I replace the loop. But the ground fault is still there.
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Doorman
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#3
In reply to #2

Re: Ground Fault on Fire Alarm Panel

10/20/2010 11:29 AM

In your history log, does it give a 'Code21'? This indicates 24VDC short somewhere.

And rather that play '20 Questions' (one of our least favorite games), tell us model number, number of active zones, description of appliances, was this working and then suddenly stopped...

And most important, why is your alarm contractor not working on this trouble? This sort of thing is part of their annual maintenance fee.

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uchesteve
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#6
In reply to #3

Re: Ground Fault on Fire Alarm Panel

10/21/2010 8:40 AM

The System is Bosch UEZ 2000 LSN. There are 3 active zones and all are working perfectly fine, safe for this ground problem which the panel is reporting.
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chrisbrit
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#4

Re: Ground Fault on Fire Alarm Panel

10/20/2010 11:30 PM

Doorman suggests that the alarm company includes maintenance as part of the annual monitoring fee. Mine charged me $180 to change a 12v battery in one of the wireless components. Shortly after that I called again to report that my siren was not working. He quoted another service call + parts. A friend just found that the siren had been disconnected entirely at the box. Two smoke detectors had been wired to an unused speaker circuit so they were not working. I can only conclude he was setting himself up some more moneymaking opportunities. Sure wish I could prove the case. I just plan to find an independent monitoring service as I own all the equipment.

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Doorman
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#9
In reply to #4

Re: Ground Fault on Fire Alarm Panel

10/21/2010 9:48 AM

Your story is horrendous! An example of the scoundrels that populate the industry at its worst.

It would be difficult to tell if the incorrect connection was simple incompetence, or as you suggest a VERY unscrupulous tactic. Either way, I agree another method is appropriate and prudent.

Most alarm companies (this is a VERY generalized comment) are designed as self-perpetuating entities. Maintenance contracts, proprietary equipment and documentation, date sensitive equipment... when you are on the hook, it is difficult and expensive to change.

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chrisbrit
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#11
In reply to #9

Re: Ground Fault on Fire Alarm Panel

10/24/2010 5:49 PM

Thanks for responding. All I can think to do is call the company, confront the owner (also the offending tech) and tell him I plan to post a complaint with the local Better Business bureau.

A friend has recommended a simple monitoring company. They offer support for the equipment I have. I'm just hoping I don't need some code that only the installer has.

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#5

Re: Ground Fault on Fire Alarm Panel

10/21/2010 12:19 AM

From my experience with a different fire protection system- you must use a resistor in place of the loop terminals if you decide to remove a loop. Measure the resistance of a "good" loop and replace it with a resistor of similiar value. This is how we pinpointed what loop was ground faulting. Check all junction boxes for any nics or cuts in the wire. We had to tape up several small nicks in the wire in order to clear the fault. Good luck
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uchesteve
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#7
In reply to #5

Re: Ground Fault on Fire Alarm Panel

10/21/2010 8:45 AM

ok thanks. will try this and see the outcome.
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tpiecora
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#8
In reply to #7

Re: Ground Fault on Fire Alarm Panel

10/21/2010 9:24 AM

For the sake of simplicity and sanity (which fire alarm ground faults are notoriously opposed to) remove all wiring except the main power supply and batteries and reset the panel. If the ground fault trouble is still present then it is either the power supply or the batteries. Disconnect the batteries and reset. I have had batteries start leaking a bit on the bottom and ground out to the panel enclosure. If the ground fault is still present, reconnect the batteries and disconnect the main power supply and reset. Occasionally a motherboard will go bad and the board will ground out on the mounting posts. If this is the case there is little that can be done.

If the ground fault trouble clears when you remove the other wiring then place each circuit back on one at a time until it reappears. Whatever circuit you just landed when the trouble comes in is the culprit. Then do as mentioned above and carefully inspect all devices and junction boxes. I would recommend lots of tape. If the circuit is rather long, go to the middle of it and disconnect one side and see if the trouble clears. If it doesnt, you know that it is towards the panel, and work your way back. If it does clear, move further down the circuit and try again until you narrow it down to one section of wire.

All this is provided of course with the assumption that you are qualified to do all that I mentioned :) If you aren't then call someone who is. That will be better than frying the board yourself.
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WJMFIRE
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#10

Re: Ground Fault on Fire Alarm Panel

10/21/2010 12:15 PM

A ground fault on a Fire Alarm panel is caused by two things only. Any wire on the system shorting to ground, or a panel failure. There is only one way to determine which is the culprit. Remove ALL wires from the control panel terminals except the power wires (not one at a time; remove them all). With all wires disconnected, a continued ground fault indicates a panel issue. In this case the issue MIGHT be a power supply problem, but could also be an internal panel component failing to a grounded position. If the ground fault clears with the wires removed, reconnect the wires one at a time (not one circuit at a time) remembering to power down and back up between reconnects. Eventually you will find the culprit wire.

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Anonymous Poster (1); chrisbrit (2); Doorman (3); tpiecora (1); uchesteve (3); WJMFIRE (1)

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