32 - Metering a Ground Fault - Introduction to Fire Alarms

In this video I show how you would go about troubleshooting a ground fault, in this case one that occurs on a NAC circuit off of an FCPS. However, the same procedure would be followed for any type of ground fault.

[@haydhn1474]

12:30 Thats a really cool way of doing it! I was scratching my head on how I can troubleshoot a ground fault with no ground reference around the device. Thanks for making these videos, I've watched multiple and they've seriously helped me out.

[@paulsheehan9246]

Fire alarm systems are at times frustrating when it comes to tracing and troubleshooting ground faults. I think the video is very informative. You did a great job explaining the wiring of the circuits and the Understanding of the circuits is very important when trying to trouble shoot Ground faults opens and short circuits etc. I have been servicing maintaining and 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. Always Both wires of the circuit Allot of electricians miss that and they spin their wheels The key here is at this point is to keep breaking the faulted 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 Fluke 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 300K ground could be from a Wiring issue or from an input monitoring point. The video was very good in explaining how to troubleshoot the 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!!

[@gordonbombay7237]

This guy rocks! Thanks Joe!

[@jorgeruiz3802]

Thanks for all your videos. God bless you

[@one_day_at_a._time]

OL actually means Open Loop, thanks for these videos!

[@thadeusbaggins9967]

As an easy mnemonic device, sure, but for most manufacturers, OL denotes "overload."

[@michaeltill1854]

Great video and explanation. Glad to see you posting again. I started watching your videos six years ago and since then nothing has come even close to the level of clarity your videos provide. Do you have a patreon or anything?

[@JoeKlochan]

Thanks. Someone else asked about that so I put a link at the end of the videos. It's not patron because they seemed to want a subscription model rather than a one time donation.

[@salvarez3169]

Thanks for the video, it’s a great help

[@melvinmanzanares197]

thank you for all your videos very good info. I work with EST 3 systems, I have found contractors bypass the ground faults with a jumper on the board, the problem is when we have to replace the RPS! And the ground fault lights up. The way I troubleshoot faults is process of elimination on NACs then move down the circuit until we find it, usually a wet device! a visual inspection around the building and asking questions on water damage to staff helps a lot. I will be taking my NICET level one on Saturday I'm really excited and nevious at the same time.

[@JoeKlochan]

Excellent, good luck! If you don't pass on the first try, it will still be good experience to get you used to the test and prepare you to retake it. Get used to using the index in NFPA 72! If you get a question about a pull station, go to the index, look up pull station, and it will tell you every page it appears on. Again, good luck!

[@carlh4279]

I rip a lot of est3 s out and replace them with something that actually works and rid ourselves of map faults. Although I will say map faults make us a lot of money.

[@andrewchen5188]

YOU ARE A SUPER STAR! thank you for sharing your knowledge with the world the fire alarm industry needs you ^_^

[@pavel5033]

Great video! Thanks

[@Cornbread12345]

Good job man!

[@jasonnunez7276]

Good video thanks I will use this method on the field 👍

[@frazierg0325]

Yo Joe. Thanks.

[@dallashill23]

Holy shit you're back!!!!!

[@ahmedgafar1697]

Thank you... from EGYPT

[@robdavidson1293]

Good stuff!

[@JohnSmith-mk1rj]

NAC circuits will have supervisory voltage on them when on standby. 24vDC circuits might be reversed when on standby (positive and negative will be reversed), this is common on older systems. Other systems will have 4 to 7vDC on them to supervise the circuit when not in use. A quick way to locate a ground fault on NAC circuits is to determine the normal voltage for these NAC circuits and then place your negative meter lead to ground and check the voltage on every wire with the positive lead. A ground fault will pull voltage down on any wire that's grounded. This will usually cause the panel to push the voltage up on the other leg of the circuit. This is a great way to find multiple ground faulted circuits when you have lots of them. Then it's just a matter of cutting the grounded circuit(s) in half, metering forward and backwards until you isolate your fault and (hopefully) fix it. This same procedure works on SLC circuits, but they're a little easier to determine what circuit is grounded since there's usually less of them. This procedure works perfectly on hardwire circuits, and theory wise it works on 2 wire and 4 wire circuits of any type.

[@iasystem838]

Thank u

[@juliosalazar6502]

Hey Joe, I know that intermitten ground faults are a pain and special in a big property where you could have added resistance from different outputs etc.. that could add up and meet the FACP or power supply manufacture threshold. I was looking at the FLUKE 1587 FC insulation meter ($$$). Don't know if you have heard of it, its good for ground faults on motor windings and sorts. But it might be a great tool for the meggers resistance. What do you think? This meter might be worth it?

[@JoeKlochan]

That's an interesting question. I don't know anything about that meter, so I can't fairly say. In my opinion, I would try to build my own cheap ground fault meter with an analog ometer and a bunch of batteries. Several people have written articles or made videos explaining how to do this. I have never done it, but I'm interested to try it. Sounds like it would cost about $30-40, rather than $900. But having never used the meter you mentioned, I can't really say.

[@tbyrd9772]

Class B circuits opens the returns. If you take your meter and measure in ohms between the input #1 - and return #1 - you will read an open if the nac panel has a true trouble on it .A lot also depend if your panel FWR . If you use a second input the same thing applies , however in class A this does not work the same you must wire to the trouble contact 's.

[@darrellhatfield5944]

At what resistance would you start looking at the devices on a circuit vs metering the loop looking for a direct short to ground?

[@sherpaderpa1]

Hey Joe, any ideas on what might cause an intermittent ground fault on a speaker circuit, or a persistent, intermittent ground fault in general? For instance a ground fault that comes in approximately every 72 hours give or take, but only lasts 20 seconds and then clears itself. No obvious reason why, the speaker circuit isn't active when it happens, fault seems totally random. Your videos are great, I'm an electrician by trade but because I watched your videos I have been able to troubleshoot many FA related issues at my facility. Saved me from having to pay to have a fire alarm tech preform a service call. Thanks!

[@JoeKlochan]

What kind of system is it? What manufacturer?

[@sherpaderpa1]

Edwards EST-3

[@JoeKlochan]

Ok, I don't know as much about those panels. You can usually meter for DC voltage between system negative and ground, and watch that value change as you disconnect the circuit with the ground on it. I would disconnect your speaker circuits and meter them to ground. If you have one that's around 300-500k, go hunt it down. You'll be able to find and fix that.

[@lockwisellc342]

Moisture

[@MJHDarknite]

Intermittent ground faults are a pain in the rear. If it isn't showing on the panel it probably isn't going to read anything abnormal. About the only way I know is to start taking a circuit off for a given amount of time and seeing if it comes back. If it still comes in, you know it isn't that circuit. Once you find the circuit start splitting that circuit for a given amount of time until you've narrowed it down. This could take weeks to trace, but it's impossible to trace a ground fault in 20 seconds. If anyone has a better suggestion please enlighten me. It's very discomforting and keeps me up at night having to leave a portion of a fire alarm system disconnected for an allotted amount of time. Some potential causes: -Moisture can be coming and going in a box some where. Outside weather in an outdoor audio device. Places like food processing plants can build up condensation during night time cleaning hours and then when their machines start up in the morning the environment turns hot and dry. I was recently at an event center where soda from the stands was dripping down below and getting in a speaker/strobe. -If it's a gf that shows up at a specific time of day it could be temperature related. I've had gfs that were caused by a pinched wire between two pieces of metal, and the metal expanding and contracting with temperature was cause it to ground at specific times of day.

[@LuisAlbertoSerranoAlonso]

I've had a very strange experience where I had a ground fault and nothing I tried would clear it... That is until I disconnected the batteries... One of the batteries was causing the short to ground and I have no idea how...

[@monikhan6982]

How can remove wiring fault...?

[@wilson9hern]

Hi , I Have. a question How Can You Trace A Ground Fault On A Addressable Loop

[@coreyyarmock4233]

How would I monitor a booster panel for troubles ?

[@benjihoggins6403]

What a helpful video. I have a question if you can help. I'm working on a Notifier NFS2-3030. I'm getting a horrible intermittent ground fault trouble coming from guest room sounder bases at this hotel. The device is causing the ground fault, but how do I troubleshoot a ground fault that would appear for 30 seconds and clears for 15-20 minutes. At some times clears for 2 days and then spontaneously comes back as intermittent. At this point I'm frustrated because I can't read ground on my meter to the lines... when things clear up so long and causes a trouble so briefly. Any ideas? Other than change out all the devices on 9 floor hotel😅?

[@JoeKlochan]

This could be a pretty big problem. There are a lot of variables. You can email me, I will help as I can, but it might be a bigger thing than I can help with remotely.

[@benjihoggins6403]

@@JoeKlochan thanks for the quick reply... any help will be much appreciated

[@JoeKlochan]

What is your power source for your sounder bases

[@benjihoggins6403]

@@JoeKlochan the way its set up now; its from ACPS 24 volts. And that is power through the main power supply

[@JoeKlochan]

I have a couple of thoughts. First, when I was fairly new in the industry we had a similar problem to what you're describing but it was on a new install. I don't remember what the solution ended up being but I think the problem had something to do with a conflict between the FCPS panels we were using for sounder base power and the main panel. If this is an existing setup and the problem recently started, I'm thinking maybe a different type of meter may help you. I have not yet built one of these myself, but the idea is intriguing to me. Google "build a low voltage insulation tester". The idea is you only have a 9 volt battery in your meter, and when you meter resistance, you're putting a very small voltage on the circuit. Sometimes there's not enough power from your meter to make it through a pinched wire or some faulty insulation. A meter like this would theoretically help with that. As I said I haven't done it, but I would like to. This may help you, it may not. You may be dealing with some sort of voltage conflict. Does the ground fault clear when you remove the 24 volt power circuit?

[@coctimusprime1872]

Hey brother got a GF on a system ive taken over a job site its a complete nightmare and im still new to this bosses threw me in this with brainless helpers, I have voltage as well on one of my PLink wires they instead of running 4 used 2 16/2 for the += AB. When i meter it on AC i was getting up to about 3. - 60. even seen it spike to 115 once.

[@emmanuelvalencia9110]

What is com/fault terminal for?

[@Fahrenheit4051]

Klochan's Not Dead

[@GrexTheCrabasitor]

anyone else tape their leads between eachother to prevent shorts/grounds or do you see it as a waste?

[@crayons071]

Are you familiar with Simplex?

[@mab1120]

Yes

[@defritzel]

Uh what? OL means open line

[@tbyrd9772]

Every find a ghost , that's whats it's like finding ground faults. lol

[@GrexTheCrabasitor]

t taps that go everywhere, god i love t taps, so much fun to trace.

[@alfalasitechgroup7]

Y u r teaching a very hard way,

[@electricalcontractor6944]

OL means open loop or open line not overload.

[@elgato897]

OL = Over Limit = too big to measure = Open circuit

[@fogrunr5075]

OL = Open Loop