Elk M1 Gold Resistors Needed

elias1693

Member
I will have 13 wired zones. Each zone will have only one sensor except zone 13 which will have two run in serial or parallel (hidden door sensors for french doors). Do I need a resistor on each zone 1 through 12 or only zones withe two or more sensors such as zone 13?
 
I will have 13 wired zones. Each zone will have only one sensor except zone 13 which will have two run in serial or parallel (hidden door sensors for french doors). Do I need a resistor on each zone 1 through 12 or only zones withe two or more sensors such as zone 13?

You don't need resistors on any zone. Only if you want the extra security against someone trying to short out your zones to bypass your sensors. If you decide you want that extra security you would put a resistor on each zone that you want that protection, no matter the number of sensors, at the farthest end of the circuit. Otherwise you can just configure the zone as normally open or normally closed (depending on what the sensor requires) instead of EOLR.
 
Just to add one more point, eolr's aren't only for someone purposely shorting your zone, it is also good for accidental zone shorts, like nails and screws through wires.
 
Just to add one more point, eolr's aren't only for someone purposely shorting your zone, it is also good for accidental zone shorts, like nails and screws through wires.

Yeah that's true. Basically with an EOLR on the circuit, the voltage is different if it is closed or if there is a short, a short bypasses the EOLR so the voltage is higher. That means the panel can tell the difference between a closed circuit and a short. That's also the reason for putting it at the farthest end of the loop that you can. Any shorts occurring after the EOLR would not be detected, so if you install it with the first sensor it won't detect shorts after that.
 
And another clarification - if you tie two french doors together on one zone, that's only one resistor. Same thing if you group windows - you pick a spot theoretically the furthest from the panel and put the resistor there.

And to be honest, they're rarely added to residential installs (not saying they're not nice to have, but rarely do people bother).
 
An EOLR on a group of series wired points,especially with multiple home runs, no matter if it's wired at the furthest point, really doesn't do much as far as supervision for shorts on any pair except for the one with the EOLR installed.
 
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