Summits burnin...

by **Bara** » Sun Sep 28, 2008 7:06 pm

Hello to all, I was called to help someone with their fire alarm that had been going all night. When I got there I found two alarm glasses broken and wires disconnected from the fused junction box feeding the alarm unit, turns out they had a bit of a party :roll: :shock:

I jammed the pins back up in the glasses so that I could silence the alarm. Checked the wiring with a non contact tester which proved there was a live feed but when I used a test lamp across L and N there was no light and same to earth. I noticed there was black around the live terminal as if they had touched to earth (maybe the party had a touch of the Major Tom about it :wink: ) anyway could someone enlighten me to the problem and a solution into the bargain. Oh and yes I did prove the test lamp.

Best regards.

by **ericmark** » Mon Sep 29, 2008 8:06 pm

The fire alarms I have worked on have resistors and are neither open or closed circuit but a resistance to the control panel that way the panel can detect tamper.
I will guess each make is different but this is really a specialist subject.
Eric

by **Bara** » Tue Sep 30, 2008 8:55 am

:D
Ye thanks Eric, solved the problem, just evicted the tenants and bingo :wink:

All back together and working, thanks again.
Not sure why but the live feed was showing as live with the non contact tester, could have been a number of factors. Traced through the spaghetti to the fuse which had blown. Replaced, connected, switched on the fuse box and viola mains power restored.

Best regards.

by **ericmark** » Fri Oct 03, 2008 10:55 am

Thank you for reminding me a fuse when it blows can often allow enough current to track and light a neon tester.