FIRE ALARM WIRING

Status
Not open for further replies.
gadfly56

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
horsegoer said:
Do all system classes always get wired alternated circuits(A/B)?? THanks.
Click to expand...

No. This is a matter of choice. Since it is an added expense, we would only quote it as an option or if required by the job specs. And I've never heard it applied to anything other than A/V's.

nhfire77:

Devices installed so they are supplied by separate circuits to the FACP. A/V's in a long hallway:

----A----B----A----B----A----B----

Where all "A's" are tied together separately from all the "B's" which are tied together. The "A's" go back to NAC 1 and the "B's" go back to NAC 2. The theory is that if one of the NAC's fails for whatever reason, you are at least partially covered by the other NAC.
 
A

Alwayslearningelec

Senior Member
Location
NJ
Occupation
Estimator
nhfire77 said:
Ummmm.... What?
Click to expand...

I know sorry.....I swore my questions would be more precise.

If you have fa devices on a loop/circuit do they always get wires A/B, meaning 2 pairs of wire of (1) 2pair? Can you have a system where there is no A/B or alternating circuits..meaning the same circuit hits consecutive devices? Thanks.
 
N

nhfire77

Senior Member
Location
NH
Oh OK, I have no idea how you figured out that's what he meant, I thought was talking about circuit classes.
gadfly56 said:
No. This is a matter of choice. Since it is an added expense, we would only quote it as an option or if required by the job specs. And I've never heard it applied to anything other than A/V's.

nhfire77:

Devices installed so they are supplied by separate circuits to the FACP. A/V's in a long hallway:

----A----B----A----B----A----B----

Where all "A's" are tied together separately from all the "B's" which are tied together. The "A's" go back to NAC 1 and the "B's" go back to NAC 2. The theory is that if one of the NAC's fails for whatever reason, you are at least partially covered by the other NAC.
Click to expand...
 
N

nhfire77

Senior Member
Location
NH
horsegoer said:
Anyone know of a good book/video where I can learn more about fire alarm systems/wiring? Thanks.
Click to expand...

Since you have no installation experience (right?)

This is a good book. Hopefully you've walked a few jobs during the rough in so you'll have the visual experience to understand the concepts. Its not cheap though

The brown book
 
peter d

peter d

Senior Member
Location
New England
One thing about fire alarm wiring rules is there is no universal standard or code. This is very much a local issue and varies widely from state to state and even from city to city within the same state. I have heard of that being done in Boston so perhaps it's a city code, or a job spec.
 
R

rockwill

New member
Location
miami,florida,usa
Hi,
Black is almost always the HOT unless someone has wired something wrong. White is most likely neutral. Green should be ground. You can check this by using a meter set to AC. Meter the black to white, you should see around 110-120 volts. Meter the black to green, you should still see around 110-120 volts. Meter the white to green, you shouldn't see any volts. If you change the meter setting to continuity check and meter the white to green, you should see that as "closed". The yellow wire in your home is most likely the interconnect. You can meter that to white and green on the AC setting and shouldn't see any voltage.
 
Status
Not open for further replies.
Top