BAFFLING smoke alarm problem

[SeanSparky]

Hi, I'm absolutely baffled by this and wondering if anyone can see an answer or have ever came across this problem.

Basically I have a smoke and heat detector interlinked, nothing fancy.
Feed is from the light closest to it.
T&E feed-3 core interlink.

When both smoke heads are on, the light turns on and in the off position it just dims down, doesn't go off.

Take 1 head off and the light works fine, doesn't matter which head you remove.

The T&E feed is 100% a perminent feed.

Please please somebody explain this for me because I'm baffled

 

[Gazthesparky]

sounds weird to me have the smoke detectors got lights inbuilt into them??

all i can think is have you connected the smoke detectors wrong at the lights ? have you picked up a switched live ? or maybe you wired them in series ? Have you confirmed you definitely have Live and a Neutral supply rot the smoke detector ??

pictures will help

 

[davesparks]

It sounds like youve wired the smoke alarms in series with the light.

 

[Octopus]

What did your dead tests show you?

 

[SeanSparky]

This is all I have added, from the junction box onwards. Lights work completely fine with only 1 heat or smoke, doesn't matter which one i disconnect.

 

[westward10]

Are the green indicators on at the detectors.

 

[Midwest]

Wots the connections in the box marked 'X'? Are you sure you haven't mixed up your, lives, switch lives and neutral?, i.e. neutral as live (or switch live) and live as neutral

 

[SeanSparky]

Yes they are on, and as I say, they both work fine if you remove any 1 detector, it's only when they are both plugged in that the light switch doesn't do its job

Are the green indicators on at the detectors.

 

[SeanSparky]

That's the standard pendant light, Swithed live, N, and loop,
I've jumped off the loop, N and earth

Wots the connections in the box marked 'X'? Are you sure you haven't mixed up your, lives, switch lives and neutral?, i.e. neutral as live (or switch live) and live as neutral

 

[westward10]

Disconnect the lot and reconnect double checking all connections.

 

[Wilko]

If all else fails, I recall a thing about smoke and heat not always compatible for interlinking (hopefully not imagined) - perhaps try removing interlink to heat and see if it changes behaviour?

 

[Octopus]

What make of smokes?

What dead tests did you do?

 

[SeanSparky]

I pretty much have done, but also the detector bases have just got a connector block for the T&E/3core. You then have a short lead to connect into the connector blocks and the other end has a little plug in connector to plug into the detectors, and with the detectors unplugged the light works fine, so that should mean the hard wiring is fine doesnt it ?
Even works with just 1 detector plugged in so my best guess is it's something to do with the 3core, most likely the interlink core ??

Disconnect the lot and reconnect double checking all connections.

 

[westward10]

Can you post pics of all three connections.

 

[Octopus]

I pretty much have done, but also the detector bases have just got a connector block for the T&E/3core. You then have a short lead to connect into the connector blocks and the other end has a little plug in connector to plug into the detectors, and with the detectors unplugged the light works fine, so that should mean the hard wiring is fine doesnt it ?
Even works with just 1 detector plugged in so my best guess is it's something to do with the 3core, most likely the interlink core ??

So no dead tests then....

 

[davesparks]

what have you done so far to try and identify the problem? What tests have you carried out and what were the results?
In my opinion the symptoms suggest a series connection of loads when they should be in parallel, so would probably measure the potential across each load and at each point wrt earth.

 

[SeanSparky]

No I'm not at the job now, I'll be back tomorrow to sort it out.

Can you post pics of all three connections.

 

[davesparks]

Even works with just 1 detector plugged in so my best guess is it's something to do with the 3core, most likely the interlink core ??

Guessing? Are you a plumber?

 

[SeanSparky]

They are both BRK brand supplied by the customer.
The dead tests show nothing out of the ordinary.

What make of smokes?

What dead tests did you do?

 

[SeanSparky]

This has crossed my mind also but I'm assuming All BRK brand detectors should be able to interlink
Can't find anything online

If all else fails, I recall a thing about smoke and heat not always compatible for interlinking (hopefully not imagined) - perhaps try removing interlink to heat and see if it changes behaviour?