Common Fire Alarm resistor values?

[EvanVanVan]

Hello.

Full disclosure I'm a Fire Sprinkler Technician and not a fire alarm technician but hopefully my question is simple enough that I'm deemed qualified to ask it lol.

I only deal with low voltage fire alarm wiring as is connects to sprinkler systems, waterflows and tamper switches basically. Every once in a while I'm unlucky enough to have an EOL resistor break on me as I'm replacing it.

I did some googling and saw that 4.7k ohm resistors are relatively common so I just ordered a 100-pack off of Amazon just to keep on the truck, just in case.

Are there any other common resistor values I should keep on hand? I saw 2.7k ohm resistors mentioned on one site, but I also know alarm work can be quite proprietary so before I ordered more I wanted to double check with some people in the know.

Thank you.

 

[iwire]

They are cheap enough to just get a large assortment pack of various values.

Don't forget you can use more than one and put then in series or parallel to make a value.

Two 10 ohm resistors in series is 20 ohms of resistance.

Two 10 ohm resistors in parallel is 5 ohms of resistance.

 

[EvanVanVan]

They are cheap enough to just get a large assortment pack of various values.

Don't forget you can use more than one and put then in series or parallel to make a value.

Two 10 ohm resistors in series is 20 ohms of resistance.

Two 10 ohm resistors in parallel is 5 ohms of resistance.

True, that makes sense...and thanks for the tip about series and parallel, I didn't know that.

For any others wondering I found out today Notifier uses 47k Ohm resistors. I believe it's Silent Knight/Honeywell that uses 4.7k ohm.

Thank you!

 

[low_voltage]

DMP use 1k resistor's and some zones use 3.3k. Bosch uses 2.2k and Mircom uses I think 4.7k or 47k. In other words it depends on the system being used and each panel can have several different resistor measurement between zones one thru eight using one measure and zones nine and ten using a higher value and when using addressable modules it may be the same or different.

 

[Besoeker]

Hello.

Full disclosure I'm a Fire Sprinkler Technician and not a fire alarm technician but hopefully my question is simple enough that I'm deemed qualified to ask it lol.

I only deal with low voltage fire alarm wiring as is connects to sprinkler systems, waterflows and tamper switches basically. Every once in a while I'm unlucky enough to have an EOL resistor break on me as I'm replacing it.

I did some googling and saw that 4.7k ohm resistors are relatively common so I just ordered a 100-pack off of Amazon just to keep on the truck, just in case.

Are there any other common resistor values I should keep on hand? I saw 2.7k ohm resistors mentioned on one site, but I also know alarm work can be quite proprietary so before I ordered more I wanted to double check with some people in the know.

Thank you.

You could probably buy a sample kit of the full range of E12 or E24 resistors from an electronics hobby store or an electronics distributor for not a lot of money.
But, for your low voltage work, probably 1kohm to 10kohm would cover most of your EOL applications.

http://www.ece.uidaho.edu/ee/classes/ECE311.old/docs/lab2/Standard E24 Resistors.pdf

 

[gadfly56]

Please keep in mind that particular panels may require higher wattage resistors than typically found in your Radio Shack 500 piece assortment which are usually 1/4 watt. As an example, the Siemens ZIC-4A card, that provides power to notification appliances, uses 24K 1 watt resistors. Also, tolerances may be tighter.

The resistor part numbers are usually included on the parts list for the panel UL listings. Using another brand of resistor might be a violation of the listing even if it works perfectly.