Fire Alarm wiring question.

[peter d]

Re: Fire Alarm wiring question.

Bob,

2)How far apart are the initiating circuit raceways from the notification circuit raceways?

What's the deal with that one? I don't see anything in the code that mentions that. The FA they just put in my old church has both circuits in one raceway, and as you know is common practice.

 

[dbrejda]

Re: Fire Alarm wiring question.

I have installed a number of fire alarms (in Georgia) and have had an Electrical Inspector question my work only once. I cable-tied some of my wires to some HVAC control wiring at the duct detectors. The Inspector asked the HVAC contractor if he had a problem with that. The HVAC contractor said no and that was the end of it. All my fire alarms have been inspected by a Fire Marshall. all they wanted to see was if there were enough horns, strobes, smoke detectors, and pull stations (if installed, rarely required) in the "right" places and not blocked by anything, if the horns were loud enough (always subjective, never with a sound level meter), and if monitored, did Dispatch get the call. The Fire Marshall also inspected the sprinkler system and checked for tampers and flow switches. So all they have ever inspected is the operation, not the installation.

I actually designed and bid one system based on the Fire Alarm Code and the customer thought it was too expensive. I had stamped prints from the Fire Marshall yet another company put in half the equipment I bid and the Fire Marshall passed the install.

[ December 06, 2004, 12:25 PM: Message edited by: dbrejda ]

 

[frankc]

Re: Fire Alarm wiring question.

MAPNET signal is a 34 volt square wave that gets in to everything. Having no support on the FPL cable is sloppy wiring practice,not code compliant, and brings that high level signal close to telco lines, PA system lines, and other systems that can induce hum and noise, and drive people crazy when trying to troubleshoot the problem. We had to eliminate the MAPNET buzz from the audio evacuation portion of a Performing arts center FA system. Our solution included reterminating shields, moving cable runs,though most of the wiring was in EMT, and using an oscilloscope to trace hum and noise voltages.
The shields should be grounded at the origin end to set up a single point grounding arrangement. This makes the shield act like a drain,siphoning off the noise voltage to ground at one point.Multiple grounding points can set up ground currents via resistance between points,and cause interference with low level audio signals. Thios technique is used regularly in pro-audio and broadcasting to reduce noise.
As others have said in this forum, FA wiring is not necessarily respected as it is power limited and low voltage. I have learned a great deal of respect for FA ckts after having to troubleshoot them.
The other problem with circuits like MAPNET is that they contain data,which could be corrupted ,if not carefully routed and terminated. This can cause missed device polling cycles,which show up as missing devices, wrong device, etc.
Spend the extra time on FA wiring, and save a lot of time later

 

[fyretek]

Re: Fire Alarm wiring question.

Often times the FA guys think the NEC doesn't apply to them because long ago no one enforced it.

I take offense to this remark dude. I am a fire guy and pretty well versed in NEC, however there are those out there opperating business's who have installers that they do not teach anything to and this is what happens. guess this is why iam union! haha gotta stabe at you guys occasionaly. To the original poster i say make them do everything that looks like crap over until they get it right! that will teach the owner of the installation co. a lesson on how to do it right. and above all do not make the final payment until you and the AHJ are satisfied.

 

[peter d]

Re: Fire Alarm wiring question.

I take offense to this remark dude.

Chill out, dude! Dave wasn't directing that comment at anyone in particular, and he actually makes a good point.

There are hacks in any specialty, but the tendency is to think, "Hey, it's low voltage, who cares!" Yeah, you might not like that, but it's the truth.

 

[dc]

Re: Fire Alarm wiring question.

Thank all of the responses to my question. Here is a follow up?
The contractor which installed has agreed to redo
What are code issues? He says there is no codes
Which indicates where the low voltage FA wires enters a metal box must be supported to the box?
He wants to put a Zip tie above the box to a new support wire he originally never installed. This support wire holds the metal Box to ceiling tile strap. The metal box is holding addressable smoke detectors in class rooms. He says you only have provided insulation at the rear hole opening, not stain relief. This is only one of many issues we are trying to get solved. Thanks again..Any input is greatly appreciated.
DC

 

[frankc]

Re: Fire Alarm wiring question.

Putting in a zip-tie to hold fire alarm addressable backbone data cable is just bad practice. The addressable loops look for ground fault and finding the fault is sometimes a real pain . If that cable gets pulled by someone and there's no strain releif, a shiner or one of the conductors gets too close to ground, and guess what? The trouble light blinks, the sonalert beeps, and the pager goes off.
If you can get armored FA cable,with the correct connectors and supports, get it. There's a code section somewhere about protection from physical damage, and that doesn't exclude the hung-ceiling jungle. Newer opinions say that FA wiring has to be id'ed,we use red paint. The reason is so that your basic hack doesn't yank on it because he knows it a LIFE SAFETY circuit. Works in theory anyway.
Bottom line; you will save yourself headaches and callbacks by starting with clean well-protected wiring paths. Getting sloppy with supervised circuits is asking for more trouble.

 

[bobq]

Re: Fire Alarm wiring question.

To all the above...your confusion shall be nevermore. Across the country the folowing applies: Electrical inspectors inspect ALL electronic installations for compliance with Electrical code. The AHJ (usually the fire marshall, but could be the same electrical inspector), inspects for operation and installation compliance with life safety and fire code. AHJ's use NFPA 101 and NFPA 72 among others as his rule books. Electrical inspectors use NEC 70.
Both inspections are required. Both inspections have different goals, and yessss they overlap. Integrity is the result....Nuff said.

 

[iwire]

Re: Fire Alarm wiring question.

Sorry Bob there is no general statement that can be made about NEC enforcement other than each area handles it differently.