I'm having problems figuring out how to connect my four wire smoke/heat detector. it is made by GE (N500 series). So, I have 3 primary smoke/co detectors made by nest that is running on a hardwired 120v. Then I have secondary smoke detectors that I ran to other part of the house such as bedrooms, hallways etc. I was reading online and I saw that many people are suggesting monitoring the power with EOL relays. Ok, so i have the 2200 ohms resistor but is the supervised relay an additional hardware I have to buy? if so, What is the major purpose of using such relay? I read where a lot of people said if one does not used supervised relay, then one will have to manually disconnect the power to the smoke detector if triggered, but if supervised one can reset it remotely, is this true. My four wire smoke detector has +ve, -ve, NO, COM. I know i'm supposed to install the 2200 ohms by the smoke detector, do i connect it to NO or COM? Could someone please shine some lights of my dilemma. Thanks
4 wire smoke connection
- Thread starter gasbie
- Start date
The relay is used to supervise the power to the entire circuit, not for reset purposes. The reset should be handled by the host panel. It's a normal system operation. It's not for a remote reset or any other purpose.
Without supervising the power, you could have a "complete" circuit electrically (NO devices) with EOLR across last device but no power at the smoke detector rendering the detector inoperable and the circuit unsupervised (requirement).
Purchase the supervision relay model listed in the installation documentation. Schematic and all required information is there.
Without supervising the power, you could have a "complete" circuit electrically (NO devices) with EOLR across last device but no power at the smoke detector rendering the detector inoperable and the circuit unsupervised (requirement).
Purchase the supervision relay model listed in the installation documentation. Schematic and all required information is there.
Thanks DEL,
I home ran all the wires for smoke detector, so does that mean i have to buy relay for each zone that I home run its wire?
Also, since am using this smoke detector as a secondary safety device, is it ok as a home run or should i connect them in series at the panel?
I home ran all the wires for smoke detector, so does that mean i have to buy relay for each zone that I home run its wire?
Also, since am using this smoke detector as a secondary safety device, is it ok as a home run or should i connect them in series at the panel?
gasbie said:
It's not a good idea to connect each smoke detector to its own zone. It will create problems when you need to do a reset after an alarm condition. DEL gave a good explanation about what happens in this thread. But if you do use separate zones, then yes, each one will need its own EOL resistor and power supervision relay.
Since your smokes are wired with home run cables, a better option would be to install 2-wire smoke detectors, and then use the 4-wire cables to daisy chain them all into a single zone back at the panel. With 2-wire smokes, you don't need a power supervision relay since power is provided over the same 2-wire pair that is used to signal an alarm.
Thanks RAL,
I do mention that these are secondary smoke detectors. I have three NEST smoke/co wired to 120V. I already bought 10 4-wire smoke detectors which I can't return. so at this point, can i daisy chain the four wires at the panel using terminal block and then put a supervision relay on the last smoke detector? Thanks
I do mention that these are secondary smoke detectors. I have three NEST smoke/co wired to 120V. I already bought 10 4-wire smoke detectors which I can't return. so at this point, can i daisy chain the four wires at the panel using terminal block and then put a supervision relay on the last smoke detector? Thanks
RAL said:
gasbie said:
I would say that the right solution is to buy 2-wire smokes, and use the 4-wire cables that are in place to create a 2-wire daisy chain.
You could then try and sell the 4-wire smokes on eBay or here on Cocoontech in the Classified forum.
Alternatively, you could pull a second 4-wire cable to each smoke location. You're the best judge of whether that would be easy to do or not.
The problem with wiring multiple smokes in parallel like that is that you can put an EOL resistor on only one of them, leaving all the others with no supervision of the signal wires.
Similarly, you could only put a power supervision relay on the smoke that has the EOL resistor. The relay is supposed to open the circuit in the event that power is lost. On the smokes that don't have an EOL resistor at all, placing additional relays there will do nothing, since there is no circuit to open.
The net is that you would have 1 smoke that is properly supervised, and 9 others that have no supervision at all. A very bad way to do things.
I realize that you will still have the Nest smoke detectors as your primary detection system, but why bother with a set of secondary smokes if you can't put your trust in them?
Similarly, you could only put a power supervision relay on the smoke that has the EOL resistor. The relay is supposed to open the circuit in the event that power is lost. On the smokes that don't have an EOL resistor at all, placing additional relays there will do nothing, since there is no circuit to open.
The net is that you would have 1 smoke that is properly supervised, and 9 others that have no supervision at all. A very bad way to do things.
I realize that you will still have the Nest smoke detectors as your primary detection system, but why bother with a set of secondary smokes if you can't put your trust in them?
The simple fact is DON'T T-Tap the detectors. It's also a non-compliant per code, even if they are supplemental devices.
While I'm not a fan of it, RAL provided the correct way to wire if there are NO OTHER OPTIONS, which is install a power supervision relay and EOLR at each smoke and then use multiple zones and deal with the additional system issues as SOP.
We're talking, what 6 detectors? $240 worth of parts MAX, which the majority of the cost can be recouped by selling the detectors.What's the value of your insurance deductible? What's the value of the property you're intending on protecting? What's the value of the human factor you're concerned about? We're not talking a ridiculous amount of money to do this correctly. Accept there was a mistake made, either the wrong number of conductors or the wrong detectors purchased for the application and move on.
While I'm not a fan of it, RAL provided the correct way to wire if there are NO OTHER OPTIONS, which is install a power supervision relay and EOLR at each smoke and then use multiple zones and deal with the additional system issues as SOP.
We're talking, what 6 detectors? $240 worth of parts MAX, which the majority of the cost can be recouped by selling the detectors.What's the value of your insurance deductible? What's the value of the property you're intending on protecting? What's the value of the human factor you're concerned about? We're not talking a ridiculous amount of money to do this correctly. Accept there was a mistake made, either the wrong number of conductors or the wrong detectors purchased for the application and move on.
Thanks guys. Am learning alot for your explanations. I do appreciate your time and effort. so what I'm doing right now is adding another 4 wires to each smoke detector just like RAL advised. However I have just one smoke detector that I won't be able to get to. So can i just use the two wire smoke detector for that, or just single that out with a four-wire smoke detector with its own supervision relay?
gasbie said:
You can't mix 2-wire and 4-wire smoke detectors on a zone.
But you're still going to be able to wire all of the detectors into a single daisy chain, even without a second cable to one of the locations, as the last detector in the chain doesn't need a return cable. So just wire things up so that the one without a second cable is the last one in the chain, and that's the detector where you will install the EOL resistor and power supervision relay.
Ok RAL, now I fully understood your explanation, could you check the picture attached and validate it for me. Seems the hard to reach zone should be considered as my first smoke detector, right? if so, I have already cut the wire short, so is it ok if I join the first smoke detector wire in a juction box to extend it to the next one?
Also, if a smoke detector is done in series, when one zone get tripped, other zone will sound at the same time, right? Thanks
Also, if a smoke detector is done in series, when one zone get tripped, other zone will sound at the same time, right? Thanks
RAL said:
Attachments
gasbie said:
Yes, your drawing is correct from a logical point of view. But realize the wiring for the detector-to-detector connections will be made back at the panel.
I don't have direct experience with the 500N smokes, but from reading the data sheet, I believe you will need an ESL 405-05 polarity reversal relay if you want the detectors to sound in tandem. A single detector will sound when it detects smoke, but to get the others to sound as well, the polarity of the power needs to be reversed. That's what the ESL 405 relay will do. You wire it in between the Elk's SAUX power outputs and the power wires to the smoke daisy chain.
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