Termination of EOL (End of Line) Devices (Smoke Alarms)

[Steve1919]

Hello All,

Had a quick questions regarding EOL devices. The fire control panel I'm using calls for an EOL capacitor (50uF, 50V) but gives no detail on how or where this should be located. I looked through a few standards and the Canadian Electrical Code, but can't find anything.

The capacitor is quite small, is it possible to just terminate it right on the detectors base?

PS. I am also interested as to why this uses a cap instead of a resistor. Does it use an AC monitoring signal? It doesn't say in the manual.

Thanks for the help!

 

[DRWeig]

Hi Steve,

Yes, we normally put the EOL resistor on the last detector's base, so a capacitor would go there too. Its purpose is to detect any faults in the wiring, so just make sure its installation will also detect the last detector base connection coming loose as well.

It might be an AC supervision signal, or it might be a DC pulse or square wave. You'd have to ask the panel manufacturer or put a scope on it to be sure.

Have fun with it!

Good on ya,

Goober Dave

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[waross]

In Canada, EOLs are often mounted on a switch cover plate and installed in a switch box at the same height as pull stations. From there they are wired back to the last detector.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Steve1919]

Thanks so much guys. I am going to design it as terminated in the base, but there is a box only a few meters away, if it doesn't fit Ill get them to move it to the box.

Thanks again!

 

[MiketheEngineer]

Be smart and call the mfg!!!!!!!