EOL wiring technique


Hi all,

I'm installing an Elk system in our new house (just about finished pulling wire) and we are not far from drywalling. I'm going to use sensors with built-in EOL resistors where possible, but in the cases where that's not an option does anyone have tips or suggestions about how to wire in the EOLs? And where did you get your EOLs from? I saw some 2.2k Ohm resistors at RadioShack and the question immediately occurred to me - how am I going to neatly wire those little devices at the end of the circuit, usually in the same hole or box as a sensor, and hide them without damaging anything? How do the experts do it?

Many thanks,
Oddly most experts do it wrong. :D

You can't use switches with built in EOL in series so keep that in mind, those are 1 per zone only.

(Shouldn't need much help with the build in EOLs as you just homerun them.)

On say 3/8" recessed door contacts with fling leads.

Strip back 4-6" of the jacket.
Cut the one lead about 2" shorter then the other.
Lay the flying leads over the and cut them with an offset matching the first set.
Strip everything back 1/2".
Twist the longest to the shortest.
Twist the shortest to the EOL and double back the EOL's contact.
Twist the last lead to the other side of the EOL and double back again.
Give the whole thing a layer of tape.

Most motions and 2 wire smokes have plenty of room for an EOL hidden inside. Just twist it inline with one of the contacts and crimp a B connector for motions. Install them across the terminals on 2 wire smokes. On motions you might have contacts for NC, C, EOL and NO. Your wires go to NC and C. On 2 wire smokes you will use NO and C, EOL goes right across them and wires connect on top then tighten. DO NOT twist the EOL to the wires when connected across the terminals on NO switches. If they come loose the EOL may still be connected resulting in no trouble detected but the smoke not working.

On surface mount contacts, often used on windows...

Most of the alarm installs I did nobody cared how many zones were in windows. I really don't think it matters much now, however complicated systems have cool factor for being able to identify them uniquely. Still I would series all the windows on a per room basis and homerun them to the panel, then you can install the EOL when you series them together. Dasiy chain them together and crimp with B connectors. If it ever becomes an issue you can always break the series apart.

Optionally you can slit the jacket and put the EOL on one of the two leads, then push that back into the wall behind or above the contact.
A few other things to think about.

The 2.2k resistors come with the ELK as well as the 820's for 2 wire smokes.

If you are using some of the motions for controlloing interior lighting, they can be programmed as non alarm and do not require an EOL, but can still be used as alarms in away mode with RULES.

I would highly recommend that you use something like the MM100 crimps (available from Automated Outlet... a few bucks for undreds of them) for all your wire to wire/wire to resistor connections rather than twist and tape. They are insulated and have silicone inside to prevent oxidation of the connections.

I usually install my EOLs inside the sensors under the screw terminals.
Too true, acdcelectric! b connectors are far preffered, if you will be building things in series you really should have them. I didn't think of that but I only tape connect the 3/8" recessed contacts however in that post I did say to do so on the wire side in the motions. I'll edit that post as the very small cost of B connectors are work it even though you'll probably have to buy 100 even though you need less then 20.
acdcelectric said:
The 2.2k resistors come with the ELK as well as the 820's for 2 wire smokes.
Having not put together my Elk order yet, are you saying I'll receive a bunch of EOLs automatically when I order my M1G panel and/or M1XIN? Also, I'm using 4-wire smokes but it looks like the same general guidelines will apply.

You get 16 resistors with the panel and 16 with the input expander. I buy the resistors by the 200 pack, they are about a nickel a piece. I do the extra fancy four state zone wiring on the motion sensors so they eat up extra resistors. Don't forget the EOL supervised relay on the smokes.