Fire alarm question

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Marqueszx

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Electrician
Why is solid wire required to feed a fire alarm panel?

another one is why it has to be ridgid pipe ?
 
As Gadfly said you'll need to unearth some antiquated rule from 5 decades ago. Just like bringing a GEC to a 30 amp disconnect, no one knows why. Regarding the solid #10's we no longer use them. We use #8 because it's stranded.
 
gadfly56 said:
It goes back to at least the 1968 code. You're going to have to find some fire department or building department old-timer to fill you in. If that happens, report back and let the rest of us know. Otherwise, all I can say is someone enjoys spending other people's money.

It's also not exactly true that fire alarm cable has to be run everywhere in raceway.

Click to expand...

The reference I use is the NYC Electrical Code Amendments for the 2008 NEC Section 760.130 (I never quite understood the hierarchy of RCNY4000 relative to the adopted Electrical Code)
 
I'm not sure what has changed since I worked there in the 1970's-80's but I remember the following issues :
  • Except for Local Law # 5 for high-rise buildings ALL regular fire alarm wiring had to be in rigid, galvanized conduit
  • NO conduits can enter the TOP of any FA cabinet. That dates back to the days of the ACME FA systems. If there was a fire in a building and the FD was pumping water into the building via the siameese connection, they didn't want water coming down into the FA panel and shorting anything out.
  • In conjunction with the FA system they had what was called a "strap key" system. That was in effect before they had reliable walkie-talkie communications. Basically it was a manual station that was operated in a stairwell by the insertion of a key the fireman had with him. If he wanted more water pumped into the sprinkler system he would activate a code to ring the gongs via the strap key to add water and another code to stop.
  • You could not use a circuit breaker to feed an FA panel. You needed a 3-pole fused cut-out with a removable neutral (usually a piece of copper pipe). You had to TAP off the line side of the service switch with no more than 10' of galvanized conduit (1 std. length). From there it was 120/208 to the FA panel. One phase to operate the panel and another (JUST IN CASE) THEY LOST THE FIRST LEG). That was in effect before they had battery back-up.
  • Electricians used to run # 10 solid even for the newer FA panels that drew about 1 amp (go figure).
Thanks for taking me back a few years. Now I'll go back to bed. :cool:
 
goldstar said:
I'm not sure what has changed since I worked there in the 1970's-80's but I remember the following issues :
  • Except for Local Law # 5 for high-rise buildings ALL regular fire alarm wiring had to be in rigid, galvanized conduit
  • NO conduits can enter the TOP of any FA cabinet. That dates back to the days of the ACME FA systems. If there was a fire in a building and the FD was pumping water into the building via the siameese connection, they didn't want water coming down into the FA panel and shorting anything out.
  • In conjunction with the FA system they had what was called a "strap key" system. That was in effect before they had reliable walkie-talkie communications. Basically it was a manual station that was operated in a stairwell by the insertion of a key the fireman had with him. If he wanted more water pumped into the sprinkler system he would activate a code to ring the gongs via the strap key to add water and another code to stop.
  • You could not use a circuit breaker to feed an FA panel. You needed a 3-pole fused cut-out with a removable neutral (usually a piece of copper pipe). You had to TAP off the line side of the service switch with no more than 10' of galvanized conduit (1 std. length). From there it was 120/208 to the FA panel. One phase to operate the panel and another (JUST IN CASE) THEY LOST THE FIRST LEG). That was in effect before they had battery back-up.
  • Electricians used to run # 10 solid even for the newer FA panels that drew about 1 amp (go figure).
Thanks for taking me back a few years. Now I'll go back to bed. :cool:
Click to expand...
Some things have changed.
  • LL 5 is out, it's now LL39, in conjunction with the butchering of NFPA 70 (2008) that NYC uses as it's electrical code.
  • I think conduit entry is still the same.
  • No strap keys anymore, at least not for new systems. BDA/DAS radios now, although the NYC flavor is different from everybody else, naturally.
  • Line side taps are still a thing, but you can run to an FA power distribution panel to feed more than one FA panel.
  • Not sure about the #10 generally, but I know when I did Terminal B at LaGuardia a couple of years ago, the Port Authority put a specific disclaimer in the project general conditions eliminating that requirement.
Have a nice nap! :)
 
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