11 - Two Wire Smoke Detectors - Introduction to Fire Alarms

I'm explaining how fire alarm systems work for new technicians or other employees who deal with these systems. This is my 11th video in a string of many Khan Academy-styled lessons. This video describes how 2 wire smoke detectors are wired to conventional panels, what happens when they go into alarm, and the limitations of two wire devices.

[@mava5634]

this man is helping a lot of electricians with these very good videos, so hats off

[@stuartmartin1426]

Joe, Just want to say thank you for taking the time to do these videos, I am starting out as a fire alarm engineer this week and these videos are brilliant. Someone buy this man a beer.

[@mohammedal-shiabh2326]

You're a legend man, keep it up

[@JoeKlochan]

Beth, if a wire is cut on a class B circuit the zone would go into trouble and none of the detectors after the open would work. If it was a class A circuit it would still work because the circuit is fed from the beginning AND the end of the circuit. However, another limitation of class B circuits is that you are limited to how many detectors on a zone can be in alarm at the same time. That usually only matters when that detector is performing an auxiliary function.

[@leonallan8602]

i dont mean to be off topic but does anybody know a tool to get back into an Instagram account?? I somehow lost my password. I love any assistance you can offer me!

[@karsynfletcher2826]

@Leon Allan Instablaster :)

[@leonallan8602]

@Karsyn Fletcher Thanks so much for your reply. I got to the site thru google and Im in the hacking process atm. Seems to take quite some time so I will get back to you later when my account password hopefully is recovered.

[@leonallan8602]

@Karsyn Fletcher It worked and I now got access to my account again. Im so happy! Thank you so much you saved my ass :D

[@karsynfletcher2826]

@Leon Allan glad I could help =)

[@messallam2011]

these traning videos are easy understood course to indicate the fire alarm system.

[@rustyshackleford8999]

You've drawn Bart Simpson or the tall cactus thing from Super Mario brothers. Great vid. It's what I needed to know

[@gundisalvjamison7611]

How do they draw more voltage? Also, how does the part known as the MOSFET work in here?

[@Aelmasri-ht5sv]

hello pls let someone answer me. i am start learning FA. i am confused because if a smoke detector activate let say second one. so the SD will short circuit and all zone current will flow into that SD and no current will be left for SD installed after that activated or short circuited SD.

[@kevinbradt835]

how do i turn a 2 wire coded fire alarm pull station into a 2wire uncoded fire alarm pull station

[@shaheerjamal1323]

How many can one install in one zone

[@leroysumerbobinageandelect474]

Hi iam sure that your you have an excellent knowledge of fire alarm but the last smoke detectors to fix the resistance it must be connected with negative born and not to the IN positive it must in OUT positive

[@everever9785]

Pls tok to Hindi