Rookie with rookie questions

Hello!

My name is Pete. I live in the Denver CO area; I’m a mechanic by trade. I have been asked by a local church to help with their fire alarm panel (among other things) problems. They had a visit from the local fire marshal, and he gave them 2 weeks to fix the problem. I’ll start by saying I used to work in 2 way communications and I have experience in system integrations and low voltage sensor systems, but I don’t have a clue about this panel. I’m looking for help. First things first, I need to identify the panel. It has a “ground fault” on it. Can anyone identify it, and furthermore help me locate a manual? Thanks so much!

Welcome to the forum. There are people here ready to help. Please give us the brand and model of the panel. We can’t locate a manual or give specific information without that information.

In general, a ground fault can be a field wire nicked in a conduit, caught between a box and the cover or behind a device. It can also be internal to the panel. Nowadays all panels have MOVs between the circuits and ground. If a surge, like nearby lightning, got onto the wiring it could blow an MOV. This usually requires a board replacement. Sometimes a ground fault can be so easy as a leaking battery in the panel.

https://www.dropbox.com/s/3ida8ykuhwhr88e/IMG_2129.jpg?dl=0

https://www.dropbox.com/s/z6030p7ldzzcgop/IMG_2130.jpg?dl=0

https://www.dropbox.com/s/or3rnp18rr2hm3v/IMG_2131.jpg?dl=0

https://www.dropbox.com/s/nbssp6bmt0twu8q/IMG_2132.jpg?dl=0

I hope I did the pictures right. It’s a Fire Control Instruments SBP. It looks like they got acquired by Honeywell maybe? I can’t get anyone there to talk to me. No surprise there, it seems that it’s gone end-of-life. It has 2 zones, and it’s showing a ground fault. So I can certainly believe that a wire got pinched somewhere. The church is going through some, shall we say “amateur” renovation, so I"m guessing someone put a screw through a wire or something like that.

I’m really mostly concerned at this point about the fire department getting a call if I start messing with it. That’s the last thing I want. It has connections to smoke detectors and to the fire alarm system too, so I just don’t want to make it worse, if I try to do some troubleshooting. I don’t know enough about this, and I can’t find a manual.

Thank you very much for your help. I certainly appreciate it!

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It has connections to smoke detectors and to the fire alarm system too, so I just don’t want to make it worse, if I try to do some troubleshooting.
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I see in the pictures there are wires landed on the two zones which would be the smoke detectors. I see wires landed on the NAC. That operates notification appliances. There could be a polarized relay attached to the NAC too.

Your statement that “It has connections to smoke detectors and to the fire alarm system too” confuses me. Is this panel for a certain area which connects to a larger fire alarm panel? Or Is this the only panel in the building? If there is a larger panel with a city connection there should be information on who to call to put the system “on test” so the fire department will not be notified. There could be a connection to a security panel for reporting.

There are no wires landed on the alarm relay contacts. The city terminals are for a reverse polarity connection to a remote station, but have no wires landed. One way this panel could activate another panel is with a relay connected to the NAC. Is that the case? Stretching my imagination to the limit, the smoke detectors could have relays that activate a second panel, but that would be very rare indeed.

I searched the internet but did not find a manual anywhere.

Usually in isolating a ground fault the wires to each circuit are disconnected until the panel clears the ground trouble. That gives the circuit. Then it is follow the wires. If the ground trouble continues with all the external circuits disconnected the problem is internal to the panel.

The building has smoke detectors connected to the panel. I don’t know exactly how many. I’m thinking several. There is also a sprinkler system and fire alarm pull boxes. The kind that have the glass piece that breaks when you pull them. I don’t know how many of those “pull boxes” there are either. Again, guessing a few at least. The connection between the panel and closest pull box is some wire mold / wall conduit. I don’t know if there’s even wire in there. So, more or less 2 separate systems. If you think this sounds like a mess, you should see their phone system. Whoa. Anyway… I tried to do a little troubleshooting today by lifting one of the zone wires at the control panel. My thinking was to try to isolate which zone was giving the problem. As soon as I did, the panel went into alarm and stayed that way until I reconnected. That was not so good. Can I just clip a resistor across those posts so I can test without the pane going off?

So when you lifted one wire from the zone the panel went into alarm? That would be the red LED for the zone, horns blowing in the building, etc. That is not normal. What should happen is the zone goes into trouble. That is the yellow zone LED on the panel and the trouble sounder making noise. That is normal and is required by code for a fire alarm panel. If it is going into alarm that could indicate some wire crossed in the field, multiple ground faults, or a panel electronics problem.

Clipping another resistor across the zone could put the panel into alarm. That is because the resistor in the panel and the one at the end of line are in parallel. The resistance across the zone is then half the normal resistance. Two resistors in parallel could make the panel think a smoke detector is in alarm.

Your smoke detectors are 2-wire devices. That is they draw their operating power from the zone. To go into alarm they add an internal resistor across the zone. That draws enough current to alarm the zone but leaves enough voltage across the zone to light the LED on the detector. This is called a current limited device.

A pull station or sprinkler flow device are just a switch that shorts across the zone wires. Those are non current limited devices.

Fair question about the alarm. Actually I think it was just the buzzer in the panel. Not sure. I hit the “silence” switch immediately. Dang I’m just paranoid about this thing. So, if I can’t lift a zone or create a resistance to test, how do I troubleshoot the wiring? Just pick through it inch by inch?

The trouble signal must come on when a zone is disconnected. That is fire alarm code. Just silence it buzzer.

If you have some idea how the wiring is run we use a technique called half splitting. Once the circuit with the ground is located, both wires disconnected and the ground trouble LED is out, start splitting. Go half way between the panel and end of line to break the circuit (both wires). Use an ohmmeter to test the circuit in both directions. Test between the wires and ground. One way should have the ground and the other way should be clear. Go halfway in that direction and break the circuit again. keep on doing that until the ground is located.

If you have no idea where the wires are run disconnect the wires at the panel and connect a phone toner to them at the panel. Use the pickup at the smoke detectors, pull stations, and other devices. When you hear the tone that wire is on the zone with the toner on it.

There are RF wire tracers but the good ones are quite expensive. You can follow the circuit wherever it goes. Maybe you could rent one somewhere if needed.

Oh I see! Ok so I should have just kept going yesterday, just silenced the buzzer. The silence switch is a slide switch, but it’s spring loaded (momentary), so in order to silence it, I’ll have to have a helper holding it there while I troubleshoot. I can do that.

Well, I’m all set.

It turns out that the #8 screw post needs a good ground. The mystery is, there was no ground wire attached, ever. It must have gotten a “good enough” ground for the last several years, and only recently just failed just enough. Thank you much for your help. I actually managed to find the manual for this panel in a file cabinet in the basement. I scanned it in, and here it is. Sharing just in case you ran into anyone else who might need it. Trying to return the favor.

Incidentally, here’s the link to all my online manuals. I try to keep that stuff in the cloud because it’s easier for me to manage. Not really any other fire - related content, but lots of other technical stuff. Heavy equipment, diesel engines, etc Just in case.

Thank you very much!