13 - Four Wire Smokes with On-board Relay - Introduction to Fire Alarms
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- Опубликовано: 22 авг 2024
- I'm explaining how fire alarm systems work for new technicians or other employees who deal with these systems. This is my 13th video in a string of many Khan Academy-styled lessons. This video reviews how 4 wire smoke detectors are wired into a power supervision relay, and it shows how the onboard relay can be used to control auxiliary functions such as door holders/closers and fire lites.
Funny thing was that by the time you had finished the video the drawing looked like an alarm clock. As a spark these videos have opened my mind to the larger picture on site. Keep up the good work.
I just landed a job in the fire system testing group at work. I have been in the HVAC industry for around 15 yrs. However, I virtually know nothing about the control interaction of fire systems. Your videos are absolutely fantastic. I searched all over and finally found your site. I feel like, in one day, I advanced weeks in my training on these systems. Thank you so much for sharing you knowledge in such an visual and easy to understand format. Please keep up the great work!!!!
Thanks for your feedback!
First, it's important to distinguish between 2 wire and 4 wire detectors. 2 Wire smokes are close to normally open contacts in a standby state. The current they draw is measured in microamps. That's how minimal it is. When they go into alarm, the detector draws more current, measured in milliamps (usually around 100 - 130 milliamps). That increase in current puts the panel in alarm.
On 4 wire smokes, the initiating part of the detector is normally open contacts, (con't)
Great Videos !! Pretty much a virtual school for new F/A Techs! Thanks man I appreciate all your effort!
Videos are absolutely fantastic!!!! Thank you Joe.
I've been in the testing business for over 2 years and I've learned a few things from these videos. I'm going for my NICET cert soon and needed a review. Thanks for making these, I've mentioned them to coworkers since 3 others in our group will be taking cert tests soon.
that´s what i kind of imagined, but now that you confirm it, it makes sense. Thanks for the explanation. All in all...your videos are great, and I give you even more props, because I can´t see you do all this on the fly. GREAT.
thanks joe for taking the time to make these videos it has opened up more work for me (an electrician ) installing alarms and understanding just how they work ,,,many thanks,,,stormin
Great video sir!!!!! very helpful information.
I haven't really looked for any of those videos. My plan is to make many videos like that in the near future. I wanted to build from the most basic concepts into more advanced ones. However, those will be difficult to make because different manufacturers use different methods of assigning addresses to their devices. Most of these methods are fairly similar, but not all. Stay tuned, I'll do the best I can.
Hi Joe, just want to say that you are doing great, I appreciate your videos, the explanations are very clear, keep going.
This is a great series of videos. Thank you for making and uploading them.
cheers mate, explained well to the uninitiated here in the UK.
That system hospitals use
Mohamad,
No, each one does not need its own supervision relay. Both the zone and power circuits would go into the first smoke detector, then out of it and into the next one. So any smoke detector along the line would have zone in and out and power in and out. Then at the end of the circuit you'd have the power supervision relay with the end of line resistor keeping the zone clear. If any one of the power wires were cut along the line, the coil would de-energize, causing an open on the zone.
Hey Joe,
First let me say these are great videos. I notice though that the 24 power supply to the door holder is not supervised. If the smoke detector loses power it will have no effect on the door holder circuit due to it is wired to a normally close state on the smoke relay. So if there is a problem with the smoke the door holder would work but not the fire light would never come on.
Ronald, you are correct. My videos are based on what I see in the field. This is what I see in Chicago at most every nursing home I go to. For whatever reason, the firelite outside the room is not supervised. If that wire were cut it would not be found until a thorough test was done. The door holder power is fail safe, so if power was lost the door would not stay open. As far as smoke power is concerned, if smoke power was lost the panel would go into trouble (because the power supervision relay would open) and someone would likely troubleshoot the circuit.
Good point. But, I guess that the presence of both an "Alarm" and "Trouble" notification would indicate that fault...just as if the door holder were actually individually supervised!
Also, if the 24V PS of the door holder is not supervised, in the presence of an "Alarm" well, at least, the door would be already opened! It's better to have it that way, than the reverse, the fire light is on but the door is locked!
That's the fail-safe mechanism.
Ronald Thompson,view multi station smoke detector commercial RUclips video link. Saving lives.
Ian Casey,View multi station smoke detector commercial RUclips video link Saving lives energy environments.
great videos! a lot of good info.
(con't) drawing no current at all in standby. When a 4 wire detector goes into alarm, the contacts close shorting the zone the same way a pull station would. Ion and photoelectric smokes work the same way as far as the current increase is concerned. I tried to attach two links to this but apparently you can't post links in the comments section. Check out system sensor .com and look at the data sheets on their smoke detectors for more info. They have ion smokes under the "400 series.
Great work ,Can youdo a video on how to read Fire alarm drawings for installers
Good explanation! I have two suggestions/questions. 1. Use a pointing tool while referring to points in the diagram. 2. You didn't mention if the supplemental relay in the detector is an add-on component or if it is an integral of the detector. I didn't ask that very well. Is the basic 4-wire detector one part number and a 4-wire detector with the ability to control lights and doors a different part number/model?
Sorry, just now seeing this. They are all separate part numbers. You can order just a 4 wire smoke detector, OR a 4 wire smoke detector with a relay. There are many different manufacturers of these types of detectors, so you'd have to consult their manuals/ordering catalogues to see the differences. There are actually far more options than just those. There are detectors with sounders, with sounders and relays, etc.
Question: could provide link as an example for resetable power source DC?
Thank you very much for informative and unique videos.
The power source is almost always the fire alarm panel. Many, if not most, fire alarm panels have resettable power built in. On ones that don't, you can take any UL listed 24 volt DC power source and run it through a relay that activates when the power is reset. If you're working off of a conventional panel, it will likely have resettable power.
Great videos! I thought that according to safety standards in alarm state the electromagnet is supposed to lose power allowing the door to be open freely.And in normal mode, power is allowed (NC) to go to the eletromagnet thus keeping door closed,
However, in this and other videos that when the electromagnet is powered that "the door should beheld opened right now"! Example 09:32.
Similarly, you say that when the electromagnet loses power (in alarm state) that "our fire door is going to close because there is no longer 24V..." (11:11)
I'm a newbie in this stuff but I'm n electronics technician by training,
Thankssss Joee so much for ur response, it's appreciated
at last i would like to ask u for a recommendation for any link of a video illustrating the addressable fire alarm loop, & how a device takes a specific address & how the FACP can distinguish it when this device go to alarm state
Joe at first i would like to tell u that ur videos are such helpful ones, as ur way of explaination is just perfect
i have a question concerning the action of a smoke detector -electrically- before & after it detects smoke
What is the equivalent of a photoelectric detector at normal state & when detects smoke?
is it open circuit then become shorted, or is it a resistor changes its value allowing increase in current that the FACP would affected by & indicates alarm..
Great videos Joe. I was wondering if you can do a video on how to supply ac power to a fuse cut out box. I've been searching but I cannot find anything...thank you.
Very helpful.
This video was helpful 👍🏼👍🏼👍🏼
And what is it for ionization one as well
Again.. Thank you very much for ur help :)
Hi Joe,
Thanks for the info. Could you please explain the difference between a low voltage fire detection system and a Relay fire detection system? Is there a way to look at the fire detection devices in a home and be able to tell the difference? Thank you for your assistance.
Awesome videos love them. Is there an addressable 4 wire smoke detector with onboard relay that works with the SLC
Can you tell me what should I ask for if I’m gonna buy this smoke detector with the relay
I mean the model or the correct name of this divice thanks
I’ve learn a lot from your videos 👍
System Sensor makes a 4WTRB smoke detector which is a four wire smoke with a relay base and a built in thermal sensor. GE makes them also, part number ESL449CRT, same thing. There are plenty of others as well.
110 smoke detector can be monitoring ?
nice video! thanks!!
Hey joe !
im ali. from iraq. i was following you since 2 years, but i didn't understand anything cuz in that time i could not talk in english. i just was lookin' at the pictures (loooool). now, i just saw your interaction with your subscribers and answering there ques. so i decided to ask you a ques : why you said in this video the smoke detector has a switch while you said in the video that you explained how does the the smoke detector reflect the light to the light sensor ?? thaks for all your videos :-)
ali allamei The simplest way to explain it is that the switch is triggered by the light sensor. If the sensor picks up light being refracted by smoke it will trigger a small circuit that will throw the switch into a closed position.
Could this wiring method be used in a motor controlled retractable door application
thanks I like this one video
So there's 11 wires entering an octagon box for that device? That seems a bit wild. Is the actual wiring organized differently than drawn?
Yeah, and I can sometimes be more than that. It's definitely a pain to work on. Haven't had to do it in many years.
i get the point when ure dealing with 1 four wire smoke detector..but honestly im not sure how to connect multiple four line smoke detectors..and does every one need its own supervisory relay?
Joe is this the same for a 12 volt system, like optic Morris? I couldn’t get it to work using a 4wb in 12 volt optic Morris system? Just using the EOL-R1 portion not the relay shown in blue
Not sure what the optic Morris system is.
First part of the video is just as previous video. I guess this is an old video and you not produce any more, but just wanted to mention that I think you worthless spending time explaining how relay or how contacts and how current in simple circuit flows, as this supposed to be just known before you do any wiring. I'm not complaining but just I think it's not fair for those who want to hear/learn fire system theory, but not electronics basics. But thank you very much for your time rolling those videos.
Do they sell just smoke carbon monoxide low voltage systems
Hi, I wonder if you can help me with my Final Year Project. It's a really simple project, but I dont know how to wiring the smoke detector with my project. Can you help me sir?
Perhaps? What's the situation?
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Do you do all of your recordings outside?
@ 1:35 you mention once againwhen the alarm trips the door closes....are they supposed to open, instead of closing for evacuation pruposes ? This is the part that I don´t seem to understand clearly.
Tony, fire doors are installed where there are firewalls in a building. Thinking big picture, a firewall is designed to prevent fire from spreading from one section of a building to the next for a given amount of time. If there is a fire in zone A, the fire doors will close between zone A and zone B. They do not lock. A person can push them open to exit but they will close behind that person. They're simply to delay the spread of a fire.
where is No. 14 video.
I just realized that the term "door holder" is used and I think that I may have mistaken it to mean the electromagnet that keeps doors closed in Access Control systems. If that's the case, well, I'm not familiar with "door holder".
"How Heat Detectors Work" was 14 and "How Duct Detectors Work" was 15.
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