End of Line Resistor - Are they a standard design?

Resistors can be gotten from any electronics supplier. Sometimes you can't get the exact spot on value and have to fudge it a bit, but unless its a really weird resistor you should be able to find replacement.

What are those [resistor] markings, and how do I read them?

There is nothing special about an EOL resistor, other than it normally has a label on it listing it as an approved/compatable device for the control panel (It may be different in the UK) . Any resistor of the correct value, tolerance and rating will work but since it doesn't have the label on it, technically it shouldn't be used. Its also possible that the panel uses something other than a resistor to supervisor the loop

Call the manufacturer direct, tell them the situation and they may send the resistors directly to you, failing that they should direct you to another supplier/installer..

This is pure specualtion in this case, but when a installer can't get a simple item from his supplier or the supplier can't get it from the manufacturer there is always the possibility that a financial dispute is clouding the issue. The installer may owe the supplier money, the supplier may owe the manufaturer money, you may owe......

Doug L

Yah you can get close...but I probably wouldn't on a fire system.

Why the heck doesn't Honeywell sell resistors for their panels? It's a minor annoyance...but still

| | Remember that 4th band on the resisitor? Gold/Silver/None? | You can get pretty close, then if your not exact: remember to look at | the tolerance band: +/- 5%, 10%, 20% then do the math- if your intended | value falls within the +/- % spec you're good to go! | Mike S. | >

| >

I'm not familiar with the products in England but it could be that the end of line resistor is a "listed" item for that particular system or it may be housed/contained within a special casing or some such. It's not that the resistor is any different than any other, it's just that in order to comply with any codes in your area, or remain within the specifications for the main panel, the installer cannot use a standard resistor.

Richard Faulkner wrote:

I don't think so. If you're looking for a 2K resistor and you find a 2.5K -

Bob

Remember that 4th band on the resisitor? Gold/Silver/None? You can get pretty close, then if your not exact: remember to look at the tolerance band: +/- 5%, 10%, 20% then do the math- if your intended value falls within the +/- % spec you're good to go! Mike S.

Most are 5%?"I do'nt think so"- I can find 10% easily. Why do you think I said "DO THE MATH"? My stupid assumption that guys who install in the field are competent and capable as well as maybe having SOME BASIC knowledge( maybe they passed a State Test?) SOME Courses go over this! What's your're thoughts on matching Wattage, Genius?

Perhaps I misunderstood what you were saying. I thought you were indicating a 20% resistor would work for any desired value within + or - range because you didn't make any mention of taking an actual measurement of the resistor value. Sorry, didn't mean to ruffle your feathers. Yes, I agree you can still find 20% resistors but they are not as common as 5%. Most carbon film

bob

And, I suppose there's a grounding terminal on that plate... js

Yes, the reciprocal resistance formula can be used for more than two parallel resistors. Or you can combine two, measure the resultant resistance and then treat the pair as one, combining it with yet another and another. And then the whole mess can be added to series resistors. We used to have a machine that would sort 10% and 5% resistors so we wouldn't have to pay for

Bob

I'd say your installer is probably lying through his teeth. Resistors are common and easily obtained at electronics supply houses.

If "blag" means what I assume it does, I'd say you're spot on. :^)

Robertm is right. However, resistor sizes are standardized and the various values are easily had. If you can't get exactly what you need you can also run two or three resistors in parallel, series or a combination to obtain virtually any value you need.

Agreed again, but that's easy enough. It looks like he's being "blagged".

(R1xR2) / (R1 + R2).

Hmm. That works for two resistors in parallel. For multiple resistors I've always used:

Rn = 1/((1/R1) + (1/R2) + (1/R3) + ...))

Thus two 8-Ohm and one 4-Ohm resistors would give you 1/(.125 + .25) =

Or 1000-Ohm and 1000-Ohm and 2200-Ohm = 407.4-Ohms.

In Canada, EOL resistors for Fire Alarm applications must be mounted on an approved End-of-Line Plate. These are usually red or off white with a resistor symbol on them. They screw to a standard single gang box. You can't use just "any plate". It has to have a ULC sticker on it. Dumb sounding, I know, but that's the way the cookie crumbles... at least in Canada. I would think the UK wouldn't be all that different.

What is unique is the resistor VALUE for the particular system. And, yes, it is a simple thing to obtain. What panel? This asshole Bass just likes to pick fights with alarm dealers.

That sounds like something Sonitrash would do to keep their response time on average -- ignore a few signals if they ever had a good day. :^)

down here in the Bahamas, noone really uses EOL ... though I have in the past, there are just no legal requirements for it here .. my last few major alarms I have though .. they look at me wierd when they turn up to one of my latest alarms and find full diagrams of the system, and EOL on every zone, since i dont do alarm service much anymore, turned over to the alarm co's, they are all 18 year olds or local old timers that dont know about EOL and why to use it, it kind of confuses them.

JoeRais> Perhaps he said end of line resistor 'relay'?

down here in the Bahamas, noone really uses EOL ... though I have in the past, there are just no legal requirements for it here .. my last few major alarms I have though .. they look at me wierd when they turn up to one of my latest alarms and find full diagrams of the system, and EOL on every zone, since i dont do alarm service much anymore, turned over to the alarm co's, they are all 18 year olds or local old timers that dont know about EOL and why to use it, it kind of confuses them.

JoeRais> Perhaps he said end of line resistor 'relay'?

The metal ones are automatically grounded. The plastic ones require you to glue the grounding wire to them. ;-))