Powering a Siren

[blafarm]

Are there any rules, regulations or "best practices" which dictate whether or not a siren can be powered using a single unused pair -- within a 2, 3, or 4 pair, 22 gauge, solid, multiconductor wire?

I'm wondering if this is acceptable -- especially if the other pairs are being used for sensors like smoke, temperature, carbon monoxide or motion.

Thanks in advance for any feedback.

 

[CORT]

Are there any rules, regulations or "best practices" which dictate whether or not a siren can be powered using a single unused pair -- within a 2, 3, or 4 pair, 22 gauge, solid, multiconductor wire?

I'm wondering if this is acceptable -- especially if the other pairs are being used for sensors like smoke, temperature, carbon monoxide or motion.

Thanks in advance for any feedback.

While I am not aware of any rule prohibiting this, I have to ask why you would consider powering something as important as a siren by something as unimportant as a backup pair of 22 ga wires in a bundle? Most people would suggest that a siren be given a higher level of importance and have its own dedicated 18 ga 2 conductor wire. This is not to say that the wiring scheme you propose won't work, but it is far from a best practice scenario. Can you at least give the siren 2 pairs of the 22 ga wire, or consider using the 22 ga pair as a trigger for an outboard siren driver. Still, if it were me, I would find a way to run a dedicated 18 ga 2 conductor wire to the siren.

 

[Steve]

The most critical thing is to consider the current draw of the siren. And you have to consider it with siren sounding, not idle. Some sirens will draw > 1 amp and you don't want that on a 22ga wire. I always like referring to this chart for wire gauge reference. You'll see a 22ga is only good for .92 amps (conservatively). If you are just using very low current piezo sounders or something, I guess you can get by with your plan, but I mostly agree with CORT and recommend a dedicated 18ga wire to be sure. You never know if you decide to change out a siren later so you want to be prepared with a wire that will handle many circumstances.

 

[blafarm]

Thank you both.

Yes, I would not have posed the question unless circumstances were such that running a new (and appropriately gauged) wire were not possible.

Just trying to determine the scope of risk associated with co-opting the only existing multi conductor wire running to that location.

Thanks

 

[BraveSirRobbin]

I like Steve's suggestion! Swap your siren out for a piezo as the current draw is in milliamps and you would have no problem running it on your existing wire (plus I'm betting the siren would be louder than your current one). Will be a lot easier than running new wiring.

http://www.automatedoutlet.com/product.php...at=0&page=1

http://www.cocoontech.com/index.php?showto...amp;#entry34611

On an off note, did you ever get to test those leaf wetness indicators?