Location of EOLRs (inside sensor or in drywall)

[SteveS]

I'm looking for opinions on the location of EOLRs.  If you have room do you put the resistor inside sensors such as glass breaks and motion detectors that have some room?  If so, do you solder the resistor to the end of one of the two non-power wires and attach it directly to the terminal or do you think the resistor wire isn't flexible enough and may break?
 
Alternately do you not bother trying to fit it inside the sensor and push it with the wire back into the drywall?
 
FYI, the sensors I have purchased so far are all NC.  It just occurred to me that if I had purchased NO sensors I could have just added the resistor across the two sensor wire terminals.

 

[RAL]

If there is room, I'd rather put the resistor inside the case vs back in the wall.  You can solder the wire, or use a B crimp connector. The wire shouldn't be flexed much once it is installed.   With the resistor inside the case, it's obvious to anyone who services it in the future that an EOL is present.

 

[Del91574]

NEVER put EOLR's inside the wall. They need to be installed at the device and remain accessible. Only exception to the rule is an item like a contact or similar.
 
In the case of powered devices (GBD, PIR, etc.) I prefer to wire them as 3 wire devices and jump the EOLR from the relay terminal to the ground and avoid splicing altogether. Those devices should always be on their own zone anyways as a best practice.

Door contacts, I prefer to always use 3/4" units for recessed applications unless there's a specific need for a surface contact or I'm stuck with a 3/8" unit. In the case of multiple devices connected in series, usually installing the EOLR in the field does not add much in the way of supervision unless you wire a true physical daisy from device to device. A branch can still be compromised without the system detecting it.
 
As far as fire, that's easy, but again, topology dependent (if you feed the loop back to the panel or not, 2 vs. 4 wire, etc.) and panic or other NO devices, the EOLR should be at the last device, again, only a single device per zone.

 

[fabriziojoe]

Check out GRI sensors as they can custom build a contact with whatever ohm you require. 

 

[Kogashuko]

So what you are saying is the way the ADT did my old panel in August of 00 by just connecting the resistor straight to the panel is a no-go.

 

[RAL]

So what you are saying is the way the ADT did my old panel in August of 00 by just connecting the resistor straight to the panel is a no-go.

 
Placing the EOL resistors in the panel provides absolutely no value in terms of supervising the zone wiring.  Some panels require an EOL resistor, and if the installer doesn't want to be bothered with installing it at the contact end, they put them back at the panel.  That makes the panel happy, but that's all it does.   Other panels, like the Elk, allow you to configure EOLRs zone by zone.  With that flexibility, if you aren't going to put the resistor at the last contact, you might as well not bother at all.

 

[SteveS]

In the case of powered devices (GBD, PIR, etc.) I prefer to wire them as 3 wire devices and jump the EOLR from the relay terminal to the ground and avoid splicing altogether. Those devices should always be on their own zone anyways as a best practice.

 

 
I thought about this but from the installation manual I can only see that it works for normally open devices.  For normally closed devices don't I need to attach the resistor in series?

 

[Del91574]

Check out GRI sensors as they can custom build a contact with whatever ohm you require. 

Would strongly recommend against this for many reasons.

 

[Del91574]

I thought about this but from the installation manual I can only see that it works for normally open devices.  For normally closed devices don't I need to attach the resistor in series?

It is if you wire the powered detector as 3 wire and jump the EOLR between the com and negative at the device.

 

[SteveS]

It is if you wire the powered detector as 3 wire and jump the EOLR between the com and negative at the device.

 
 
Thanks for that explanation, that certainly simpiified things!   Appreciate everyone's answers.

 

[johngalt]

Would strongly recommend against this for many reasons.

Care to elaborate? The only downside I see is if you switch from one panel to another company that uses a different EOLR value.

 

[Del91574]

Actually, even the same manufacturers change EOLR values depending on the host panel and even which component the device is wired to (Honeywell has changed to an extent, but they're still out there).
 
If any sort of zone rewiring or definitions are performed, there will be a resistance  issue requiring the contacts to be pulled and replaced. Also requires service spares to be maintained with the specific EOLR value, not a universal contact, so either those need to be maintained for EVERY type installed on a job or when something fails, expect the 2 week lead time from GRI.
 
Also complicates troubleshooting. Troubleshooting is done using voltage and not resistance....so a failing contact with internal resistance issues would not be easily located if the resistance is technically within spec (~300 ohms or 10% on most panels out there). Unless you've troubleshot a bad contact (cracked reed or internal corrosion inside the potting) you can't appreciate using voltage, a good analog VOM and voltage for troubleshooting. Same for checking grounds on the cable.
 
If you have anything more than a single contact per loop, unless you daisy the field cabling from device to device, the benefit of an EOLR installed in the field series loop is a moot point.
 
Most panels are monitoring 3 zone states commonly, so the ROI is even less.