How to troubleshoot a fire alarm system ground fault

[@Washburn-rr5eh]

For anyone who enjoys installing/ servicing fire alarm systems and want to learn more about using there digital meter. Set your meter to AC and then select HERTZ for frequency. Then put your meter leads on the SLC loop. Then look at the frequency changes. The SLC LOOP puts two different signals. AC riding on top of a DC signal. If you have an oscliscope. It's pretty cool to watch. Old School Tech

[@miltonaanti]

Thank you! You made this so simple and easy to understand. Every technician I’ve worked with has always made it sound extremely complicated.

[@jskjsk3986]

Nice job. I personally like to leave the loop energized to determine in and out at the device. Keep up the good work.

[@turbojoe2]

I dont know how old you are or were your position is as an electrician but I am impressed with your diagnosis of the pain in the ass ground fault. Kudos to you. Also I would normally open the circuit in the middle as a start. If you can figure out where it is. LOL F/A can be a real mystery sometimes.

[@paulsheehan9246]

Fire alarm systems are at times frustrating when it comes to tracing and troubleshooting ground faults. I think the video is very informative. But, A proper meter to use is one that can measure 1 to 2 Meg ohms Which is 1 million to 2 million ohms. The fluke model T5-1000 is great if the fault is less than 1k Ohm 1000 ohms. So, a fault that is over 1K this meter will fail to detect the ground fault. I have been servicing maintaining programing commissioning large life safety systems for over 30 plus years. So, when it comes to the infamous ground fault IE SLC, NAC, 24VDC Aux etc. Negative or positive doesn't matter. Troubleshooting is key on the approach on how to investigate the fault. Like was there any construction done recently? Known water leaks floods, roof in the building etc. This would help out the technician pinpoint the area. When breaking up the known circuit in the fire alarm panel. The Technician on site will not know how its wired (doesn't matter) The key is to break the known faulted circuit in halfway segments which once done they will know which half is causing the fault. The key here is at this point is to keep breaking the fault circuit in half's IE not Every device etc. This will be a time saver, along with never having more than 2 to 3 opens of the circuit any 1 time so you don't' lose track of the path where the ground fault is located IE class-A or B Etc. Now not all ground faults have a low resistance. Most modern fire panels will detect a high resistance ground fault IE 200K ohms or more. Now these may be from a wire that has been pinched in an electrical box or from a cable pulled tight on a metal pipe or HVAC duct or even tie wrapped FPL cable to a threaded support rod etc. There is another tool to use in the troubleshooting toolbox. Set the Multimeter to DC voltage The T5-1000 meter will be fine for this test if used. I like the Fluke 87 ($$$) but the 177 is fine anyways. etc. High resistance grounds are not easy to trouble shoot. These can be caused from Wiring faults on the input side of a monitoring module on the SLC circuit. A 500K ground could be from a Wiring issue or from an input monitoring point. The video was very good in explaining types of circuits. Most circuits are powered limited so a short will shut off the power but typically most circuits as designed to operate on 1 ground fault but NOT multiple ground faults. Voltage is key here Lack of voltage or a low voltage condition from a ground fault will disrupt the SLC communication to devices along with not having the proper voltage to operate the Horn/strobes etc. I Hope this helps the professionals in the fire alarm Tech field The more you know sure helps in daily work!!

[@nics-systems-electric]

Thanks for the comment some great information here definitely information I will keep in mind

[@laurol4342]

Excellent information. Thank you.

[@gregorynatanson6923]

Thank you, very informative. I wish you do video on intermittent ground fault troubleshooting

[@Mamba1712]

I know how to repair these fire alarms

[@achhistory5112]

Good jobs brother very good information

[@CJ9899]

Wow. You’re gonna go far in this trade man. You know your stuff well

[@nics-systems-electric]

Thanks probably Become a journeyman electrician first then maybe see about the whole fire alarm tech thing

[@CJ9899]

@@nics-systems-electric That’s exactly what I’m doing. I’m starting my first term soon in the union as an electrical apprentice

[@nics-systems-electric]

@@CJ9899 Nice I feel like it would be helpful and easier to have an electrical background and looks better to a fire alarm company if they see you’re already an electrician

[@CJ9899]

@@nics-systems-electric exactly

[@martinsnibbor7691]

This is a wild one, at our water treatment plant there was a ground fault on the slc line . I traced it to pull station where a spider had made a home and built a web. I’m a NICET 3 tech and never experienced such an issue. I did some research and found some spiders webs have a conductive protein which of course the building was metal caused a ground fault. After caulking and kicking the critter out issue solved.note that I was using a top line fluke meter , my 123 fluke or Milwaukee meter would not pick up resistance to ground. Hope this helps my felllow life safety pros.

[@nics-systems-electric]

That’s crazy I did not know that about spiderwebs

[@ob4cl257]

That's crazy. I had a runner call a few weeks ago, came back a few hours later to find ants had nested in a pair of riser 4x4's. Took out half the system. They entered through the horn strobe penetration.

[@Washburn-rr5eh]

The spider was communicating with all the devices on the SLC loop. LOL

[@justinmusicgroup]

When I trouble shoot i like to grace my faults on ohms. If you now how to use/ read the meter it makes troubleshooting really easy.

[@shamatieyss5243]

Wow thank u for sharing thats super insightful intel

[@elsiebonilla7445]

Thanks you help me out a lot at work

[@lumenfirealarms]

Very interesting video!! Nice to be back watching your videos!! ...

[@chadrowland5234]

On your meter, the letters OL means open line. I have a question, how do I know if a panel has over current protection on the nac?

[@JunPVlog]

Thank you for sharing sir new supporters here

[@joeclark6842]

I hope you join the IBEW we need guys like you. Really good video, maybe you can show how this works on paper, then give the field video. And explain why the ohms read that way and how the meter should read when in Normal state. Show how Class B and Class A ckts. difffer. The difference in a IDC NAC and SLC trouble shoot differently and when you T tap a Class B ckt how should you go about that? Just a few things.

[@DavidMoore-od9kv]

I 100% need and want the answers to those things!

[@justinmusicgroup]

Nice video bro, as a notifier programmer I enjoyed this video!

[@vintagefirealarmguy5285]

Nice video. This is uploaded on my birthday

[@nics-systems-electric]

Happy birthday

[@KP-ol3tc]

This video helped me out and pissed me off at the same time cuz I'm pretty sure the ground fault happened internally on my buildings panel! Fudge my life rn!!!!!! Great info, what's crackin now-a-days?

[@alexgrodzinsky3496]

Thank you for the video. Very informative. I have a question. What if you are moving not towards the EOL, but towards the panel. What resistance if any are you going to get?

[@Super-Mex-k]

I have found that roof leaks cause grounds more than anything. Unless someone has been working in the ceiling

[@fyrelite07]

Wow! almost at 2K! Keep up the good work!

[@jeremyrodriguez5923]

Dude! Awesome video! I'm a 3rd year electrical apprentice. I've been working on an Emergency Fuel Shut Off System that uses these NAC , EFSO Control panel , interface panel, and that in these fueling vaults are different devices such as leak detectors, liquid level switches, limit switches etc. It's a lot! We ran all the conduit, pulled wire and landed in these panels but we are just the electrical contractor, this fire company is the one helping us bring it online and commission the job. I've learned a lot by talking to fire guy, just learned about putting resistors on the end of the line. I've gotta question for ya, for these leak detectors that require a resistor at the EOL, how would you go about wiring the resistor to the wire? We tried wirenutting the resistor but it doesn't make a solid connection and there's no terminals for the device. Just 3 wires coming out it for NC, no and Common.

[@nics-systems-electric]

Thanks yeah usually the panels circuit would end on a device with terminals that you could put your wires and resistors under lots of times though the end of line resistor at least here in Canada is required to be in a separate box where there are special end of line cover plates for the box with a terminal block on the back of them for you to bring in your wires and put your resistor under i’m guessing that would be the way you would have to go in your situation

[@LeChuckMaster]

A good way to do it, other than a proper EOL cover plate, is using terminal blocks

[@DistractedHeart]

THANKS SIR KEEP IT UP👍

[@luyenhua5693]

Can you tell me what the Gen-fault smoke detector is?

[@PrieciseAlarm144]

Are you using continuity or resistance?

[@samuelbrittingham1140]

That's an interesting meter. It can do Continuity and Ohms at the same time? You never want to check for GFs with Continuity only. Always use resistance incase the copper is touching metal that isn't grounded. In that case you're only going to see resistance on the wire. Using voltage is also a great way to find grounds.

[@nics-systems-electric]

This metre is like most there is a setting to measure the resistance value and if the resistance value is not very high it will just give you a beep saying there’s continuity

[@tonytony6912]

excellent video

[@nics-systems-electric]

Thank you very much

[@georgesdibeh7826]

Great thank you but is it correct to measure ohms with the power on?

[@nics-systems-electric]

My power was not on as it was disconnected at the terminal block

[@michaelfreeman2885]

Fire panels can detect ground faults that the continuity beep can’t detect on a meter leave it landed on the panel break in the middle read DC voltage and ohms what your doing on a big job is asanine

[@RaccoonAlarmsVosgra]

I recently got a simplex 4004 and I'm pretty proud of the system although I do have trouble

[@nics-systems-electric]

What is the trouble?

[@FireAlert]

Very well explained!

[@FireAlarm33]

Why do your panels keep ground faulting? Nice video!

[@nics-systems-electric]

I’ve only ever got a ground fault once

[@FireAlarm33]

@@nics-systems-electric My Bad sorry

[@fredrickdavis5746]

Or the batteries leak by most ground are nac outside and or wet stuff or too tight connector pinched wire

[@vrryan6]

Nice

[@tonyprendergast5194]

Needed this

[@李峰啊]

厉害👍🏻

[@J19_vlogger74]

It would be so incredibly hard to find a ground fault in a real system of hundreds of devices

[@zfrenchy1716]

OL stand for Open Loop

[@nics-systems-electric]

Overload is how I know it as

[@AnaSilva-de9yj]

Ur funny nic

[@fredrickdavis5746]

Some ground faults you can’t meter

[@Washburn-rr5eh]

SO VERY TRUE!!! So what do you do when the conductors your troubleshooting have ground fault but don't show up when you have your meter set for resistance ( not continuity ) only. There a few things you can do. You can have a second tech at the panel and use that as a ground reference. Sometimes a 2nd tech is not available. If your using a good fluke ( 87V) set to resistance and your seeing a clean line. Most likely you have induced voltage or too much noise on the conductors which will also show up as a ground fault condition. So if your not seeing any ground faults in the resistance mode. Set your meter for AC Volts ( make sure conductors are removed from PCB) and see how much induced voltage is on conductors. Even to much noise on the conductors can cause ground fault. I stopped doing installs back in 1996 and became a full time Fire Alarm Service Technician. Till this day, I still service and repair over 150 different systems a year. 95% of those service calls involve troubleshooting with your meter. Somtimes there is a lot more to ground faults then just a pinched/skinned/ wire. I'm on job right now were the RS 485 terminal on the annunciator lamp driver is locking up the whole panel. Making all functions inoperative. If there are any service techs who want to know the troubleshooting process from start to finish and what solution i came up with to bring system back to 100% operational. I will be glad to explain it. I have been doing Fire Alarm Service work for 26+

[@PramodSingh-ke3fr]

Tq sir

[@therealryanbeach]

Alligator clips are a MUST!

[@miket2215]

Personally have a wago attached to each probe. Snap in the cables whilst giving a secure connection.

[@rahuln7794]

How to Repair this PCB Board

[@nosferatu2]

The Rizzistor

[@StevenTYates]

I got an easier way. Read manual to determine what resistor each zone requires and land them at the panel for each zone. I bet money the ground fault will go away for good.. 😂😂😂😂 jk jk jk don't do that

[@Dime_Bar]

Fucking hell we have a school kid thinking he knows about fire alarms.

[@nics-systems-electric]

Well I do but if you think that there is a better way to troubleshoot ground fault I would like to hear it what is your method?

[@Washburn-rr5eh]

He does know something about fire alarms. Every tech has their own way of troubleshooting. If there is something that you feel he is doing wrong. There is a thing called " constructive criticism" not being disrespectful like you are. If you think you can do better. We would all like to hear about it. I think he is doing a good job and is trying to help other techs who have been installing and want to improve on there troubleshooting skills. I am a fire alarm service technician who goes out and services/ repair over 100 different systems a year. So like I said. If you think you can do better. We all want to hear about it.