Fire-sprinkler alarm wired to an outlet


  #1  
Old 08-24-19, 01:11 PM
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Fire-sprinkler alarm wired to an outlet

I was looking to run an additional AC outlet off of an existing outlet, and then I got a look at the wiring inside it. From what I can tell, it's the wiring connecting my fire sprinkler sensor to the alarm bell on the side of the house.

In the attached image, you can see that there are three runs of romex arriving at the box. one (#2) is 3-conductor, the other two (#1 and #3) are 2-conductor. Here's what I know:
  • #1 is the supply from the electrical panel.
  • #2 runs to the flow-sensor on the pipe going to the fire sprinklers in my ceiling
  • #3 runs to the alarm bell on the side of the house
  • #1-black is tied to #2-white
  • #2-white is shorted to #2-black. My guess is that #2-white is wired to the common on the flow-sensor, and #2-black is wired to the normally-closed terminal.
  • #2-black connect to the top of the outlet. The break-off tab on the hot side is removed but the one on the neutral side is intact (so the bottom outlet has no hot)
  • #2-red is cold and is tied to #3-black, so I'm presuming that #2-red is on normally-open on the flow sensor.
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The part that triggers the alarm bell when the flow-sensor triggers makes total sense. The thing I'm baffled about is the outlet. It appears that this outlet is only for turning something off when the fire-sprinklers come on... but what? This house is part of a development tract, so these houses were all made in a bunch, so I'm presuming that this was by deliberate design (maybe even to conform to building code). Is this what the irrigation system is supposed to be plugged into or something, so that the fire-sprinklers will have maximum water pressure?
 

Last edited by PJmax; 08-24-19 at 01:26 PM. Reason: moved diagram position
  #2  
Old 08-24-19, 01:35 PM
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Welcome to the forums.

The thing I'm baffled about is the outlet.
I'm an alarm installer and I'm also completely baffled.... but as to why there should be a receptacle there on that line at all.

I'm putting this in the alarm forum as it's not really a wiring problem.
 
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Old 08-25-19, 12:27 PM
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Normally, by code, _nothing_ else is really supposed to be on that sprinkler bell circuit. On a _guess_ (without seeing how the wires are landed on the flow switch) they are just doing a pass through to power that outlet, possibly to power a future alarm communicator (one of the few things that can, and should, share that circuit). Not sure why they split the outlet.

The red should be coming off of the NO terminal to send power to the bell on water flow.

It _is_ an odd configuration, to be sure.
 
  #4  
Old 08-27-19, 12:49 PM
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Residential sprinklers are different from commercial systems. For example, plastic pipe can be used, as long as it's listed for the purpose. Short of requiring off-premise monitoring, a local bell is the best they can offer. A dedicated circuit for a bell could be tripped or turned OFF and nobody would be the wiser, so a non-dedicated circuit is within the realm of reason.
Personally, I would prefer it on a circuit dedicated to lighting. Lights that don't work seemed to get more attention that receptacles.
 
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Old 08-27-19, 02:12 PM
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Yeah, the 13D & 13R sprinklers have modified rules. How stringent they are about the bell circuit is going to depend on your jurisdiction. Florida tends to be pretty fussy, even for the residential systems.
 
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Old 08-27-19, 03:51 PM
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The OP didn't give us the full scoop on his living quarters. He's from California.

My sister lives in a 6 unit condo. The "sprinkler" audible is powered from the house panel.
It shouldn't rely on a tenants power unless each unit is completely stand alone.
 
 

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