1)Poor workmanship. Using cutters to crimp beans leaving a gap in the insulation and the gap touching a grounded back box.
2)Water or moisture from running cables in underground pipes where they get flooded and the wire soaks.
I have been asked to present a training seminar regarding fire alarm
> systems, in particular addressable systems. I am looking for common
> causes of Ground Fault Troubles that people have come across. Any one? >
From the burg loop on combo burg fire panels (where otherwise legal). Some folks use beans on the burg side, and some use cutters to crimp the beans, and some have problems with foreign grounds because of that. I have had to trouble shoot those before where the burg loop trashes the fire system for that reason or a number of other issues. One reason I hate to deploy combo burg/fire panels, especially on larger systems. I am sure I am not the only one who has had this problem.
Never tried that. I've only worked on one 250FB panel though, and it was always remote downloaded.
I did notice an anomaly with some 128FB panels that sent a TLM trouble in between tests, at test time, that's why I asked.
That doesn't appear to be a huge issue since you'll be taking your laptop with you though. I'm sure it was frustrating at the time, but you just saved a lot of us aggravation, guinea pig!
Good to know in case I run into it though, thanks $1,000,000.
In this area, the AHJ does not permit combo systems. Before that, yes, I had one on the front door of a conveinence store, and it only registered the ground fault when the door opened (every few minutes or so). Otherwise, it would go away. Talk about pulling my hair out!
The Bosch combo system can be made to ignore grounds on sec loops, and initiate trouble on fire loops..., provided they are separate (as they shall per. code) But I don't like Bosch systems... My hated comes from Radix, but now they Boooosh get the title.
The only time I've used combo systems on commercial was for smoke above the panel and pull stations for a night club, and water flow supervisory.
Here in St. Louis, per the AHJ, all commercial fire systems have to have accessible splices, which are required to be soldered and taped, with an appropriate service loop provided. Plastic splice boxes are permitted for low voltage.
If you used wire nuts here, the AHJ would throw you off the job after he finished laughing.
BTW- you won't get onto any large commercial/industrial sites here without a union card. Ours is IBEW Local #1, the first and oldest electrical worker's union in the nation.
We all know what idiots AHJs can be sometimes, but if you guys think wire nuts are not allowed on fire alarms, I challenge you to show me the code section that prohibits them.
Both power wiring and fire alarm wiring are regulated by the NEC. If UL listed wire nuts are acceptable for splicing light and power wiring, then they must also be acceptable for splicing fire alarm wiring. Of course, you wouldn't use red wire nuts to splice two 18 gauge wires, but if you use the correct size, I say it's NEC compliant.
Solder and tape is also recognized by the NEC as an acceptable method of splicing wires. Somebody show me where it says you can't splice fire alarm wire that way.
I am less confident about the use of jellybeans, since I don't use them at all. However, they are UL recognized, and so long as wire size limitations are not exceeded for those connectors, I suspect they are legal as well.
Yeah, I never liked giving those bozos my money, especially when the 'A' card guys (regular electricians, as opposed to our low-voltage 'BA' card) got all the benefits through the hall. Our dues were tantamount to paying a small bribe every month in order to gain access to the larger jobsites. When I started my company, and entertained the idea of keeping my card to access the big jobs, my "meeting" with the union bosses felt like a shakedown- 4 or
5 slimy looking guys eyeballing me and firing off questions about loyalty, revenue, etc. Needless to say, my small company didn't end up doing many commercial jobs here.
On the Trans World Dome project in '95 (which was delayed by several months mainly because of the squabbles among Local #1), we were carrying in video monitors for the camera system for the foodservice vendor, who operates a secure food and liquor storage area, and a highly secure "cash counting" room. An 'A' card foreman came over and told us to put the monitors down- he said it was an electrician's job, since they had plug-in cords. It was horse shit, but our office gave the bozos a couple hundred bucks to haul in our monitors and set them on our shelves.
I think they never quite got over the loss of FA and conduit jobs after FA went low-voltage open cable. OTOH, you'll never see any finer work anywhere in the country than that of our group of guys. Very uniform and professional.
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