EOL resistor question

bonez05

bonez05

Member
Hi all, I'm kind of new at this.

I have a EOL resistor question. I get the point of them -- for line supervision, but it seems to me that the EOL resistor should actually connect to the contact itself, rather than a few inches down the line... It seems most people install them a few inches back to stuff them in a wiring hole.

It seems like somebody could break the window and short the line right at the contact if the resistor is install a few inches back, defeating the purpose of that resistor.

Is this correct? Should the resistor be installed right at the contact point?

Thanks

[EDIT} -- i guess even if the resistor was right on the contact you could still short it there and complete the loop. All in all I guess if I was breaking in somewhere I would smash the glass at the contact and short the contact, so I'm not sure how a EOL resistor prevents line tampering.
 
Let me get this straight . . . The burglars in your neighborhood break the window and, rather than grabbing the goods and leaving, they jumper across the window sensor and then grab the goods? Or do they jumper across the window sensor and leave with the intent of returning to grab the goods after you have repaired the window?

In any case, surface contacts are usually installed with the resistor a short distance away from the contact for a cleaner look. Recessed contacts can have the resistor directly connected to a terminal. For most residential applications, the EOLR serves no practical purpose unless your panel requires one and then installing it at the panel would be my recommendation.
 
Your Edit is correct. If they short it where it normally closes the circuit by the window being closed, then eol resistor will not be of any use no matter where you put it. EOL resistors will detect shorts from things like nails through the wire or from someone shorting it at the panel or maybe in a crawl space or something. This sort of thing might happen if you have a plumber or cleaning person in your house.

Magnetic contacts would be harder to disable if you had them mounted in the window frame rather than surface mounted.

Also a glass break detector would probably be your best solution.
 
okay great. just making sure I was on point. Right now the resistors are in the control box. I guess they'll stay that way, I'm not too worried about service people in my house.
 
bonez05 said:
okay great. just making sure I was on point. Right now the resistors are in the control box. I guess they'll stay that way, I'm not too worried about service people in my house.
Click to expand...

Realize that it doesn't have to be a malicious service person. They could accidentally short a wire while performing work, and an unknowing burglar could (unlikely, but possible) choose to open that window/door, which is unprotected, since it's shorted...

That said, I am no alarm expert, but I'm fairly certain that given the above condition, your alarm (with EOLRs installed in the control box) wouldn't sense a difference, since the line is shorted - whether by the sensor itself or on the line....
 
If you're worried about people tampering with your contacts, it makes no difference if they're recessed or surface, just surface ones are easier to locate. A large enough defeat magnet will do just that.

If security is paramount, then installing balanced magnetic switches (or even Magnaspheres) is part of the equation instead of generic units.
 
DELInstallations said:
If you're worried about people tampering with your contacts, it makes no difference if they're recessed or surface, just surface ones are easier to locate. A large enough defeat magnet will do just that.

If security is paramount, then installing balanced magnetic switches (or even Magnaspheres) is part of the equation instead of generic units.
Click to expand...

Well I guess aside from the fact that surface mounted contacts tell the whole world exactly how your alarm works from a glance across the room, the only difference would be that surface mounted contacts can be disabled by virtually any tradesman possessing minimal knowledge, less than 60 seconds of time, and the tools/supplies they normally carry. Also after they disable the contact only a close inspection would reveal the tampering.

For example:
painter: break off razor blade after cutting into wire
cable guy: wrap fine filaments of cable wire shielding between contacts/temrinal screws
phone guy: wrap single strand of stripped cat3 between contacts/terminal screws
plumber: piece of solder wrapped between contacts/terminal screws
carpenter: nail/screw into wire

I'm still trying to think of the trade that normally carries a suitable magnet.

In short, disabling surface mounted contacts is a simple crime of opportunity whereas disabling recessed magnets requires pre-meditated intent as well as an opportunity to closely inspect the window.
 
BraveSirRobin, have a link for one? That may be the solution I'm looking for, plus adding a glassbreak should solve the problem.
 
You need these:

http://www.securitro...es/MSS_Spec.pdf

They'll look awesome on your windows.

If you are worried about your perimeter why not add a motion or motions as an extra layer of security?

I have to say it... EOL means End Of Line. There, I said it..

OP. There have been several discussions about EOL's, their importance, which conductor to install them on, etc. Use the forum search and you'll have hours of educational reading and then you can make an educated decision on which works best for you.
 
Yeah maybe i will add a motion, I guess I was just worried about false alarms. I have dogs, and if I forget to close off the room could be more trouble than its worth.
 
I don't know how big your dogs are, but that's why they make pet immune models... ;)

My previous alarm was from Ademco... so I've got a couple of Aurora's installed
 
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