MF smoke detector installation for ground floor

[OMGneophyte]

Hi All,
Moving inappropriate ground floor smoke detector installation from hall corner to middle of ceiling.

Original wiring is OMGrade under flooring above (currently lifted); JB (not MF) feeding mains and interlink via even nastier chocbox housing plastic screw connector box. Just about everything that could be wrong is wrong (bar the fact the detector is connected - small consolation)

Big issue with getting this MF: the new detector tails are all of 14cm. About 8cm of movement is needed to withdraw detector to update battery, leaves just 6cm. That's not enough for a Wago JB (MF). I've considered Wago light (smaller, & not MF) but the series 224 connectors won't do (detector tails are stranded). I don't get how I can do this MF.

What do experienced heads suggest?
Get a longer set of tails made up on the detector connector?

Thx

OMGW

 

[SparkyChick]

I presume by 'tails' you mean the connector cable that plugs into the smoke alarm? If so, these are single insulated and should be properly contained in a suitable box. The smokes I've fitted like these are Kidde and typically I terminate the 'tails' in a dry lining box that is cut into the ceiling.

So, in your case, I would be inclined to use a Wagobox to join the existing wiring to a short length of 3 core + earth and then terminate that to the 'tails' using Wago's in a dry lining box.

 

[Octopus]

Ask a competent spark round for advice?

 

[littlespark]

Are you moving the existing detector or replacing with new?

If this is same 90’s house as your other post, check the use by date on the detector.

It might be worth replacing all of them in the house.
Aico lithium battery, radio link interconnect lasts up to 10 years. No wiring needed

 

[OMGneophyte]

@SparkyChick, thank you, that's neat. I suspect Murdoch would not be surprised to hear "I wouldn't have thought of that"
A couple of follow on questions if I can? Do you fit a blanking plate to the drylining box? How's the tails getting through that if so? Or simply using the detector mounting plate to do that? Thanks again for your help .

Omgw

 

[OMGneophyte]

@littlespark, you're spot on, that's another reason for the work - the original are well past their best by date. Thanks for the Aico suggestion. I didn't know about them. Pity I have a brace of new BRK 670MBX.to hand

 

[SparkyChick]

@SparkyChick, thank you, that's neat. I suspect Murdoch would not be surprised to hear "I wouldn't have thought of that"
A couple of follow on questions if I can? Do you fit a blanking plate to the drylining box? How's the tails getting through that if so? Or simply using the detector mounting plate to do that? Thanks again for your help .

Omgw

If it's the Kidde detectors, I believe the mounting plate has holes spaced to allow direct mounting to a back box. Once the detector is in place, all connections are suitably enclosed.

 

[OMGneophyte]

@SparkyChick - perfect, so too does the backplate on my new detectors. Thanks a lot for sharing your experience

 

[Risteard]

If it's the Kidde detectors, I believe the mounting plate has holes spaced to allow direct mounting to a back box. Once the detector is in place, all connections are suitably enclosed.

Don't generally use Kidde detectors, but anytime I did I used their pattress with them. This will even contain block connectors to change from the fixed wiring to the plug for the detector.

 

[OMGneophyte]

Thanks. I've some BRK detectors bought & these suggestions have definitely pointed me in the right direction. Use of the drylining box will also help with getting the installation airtight in the first floor ceiling .

 

[Octopus]

Thanks. I've some BRK detectors bought & these suggestions have definitely pointed me in the right direction. Use of the drylining box will also help with getting the installation airtight in the first floor ceiling .

Air tight .............. no ..................why?

 

[telectrix]

using one of these drylining boxes means you can cut a neat hole in the ceiling with a hole saw, instead of hacking it out square with a bone saw.

 

[OMGneophyte]

@Murdoch,
Re airtight - yes, certainly.

Without the backbox it would be challenging to make the install airtight; the tails need to be movable for battery replacement.

WITH the backbox we have the slack required for movement flexibly accommodated in the box ... meaning all the entry points into the box from the loft can be sealed with a suitable intumescent.

Outcome:airtight

(I'm embarked on a massive remedial on this plasterboard tent I've acquired - would be good to hear from others with experience of achieving airtightness)

 

[Andy78]

@Murdoch,
Re airtight - yes, certainly.

Without the backbox it would be challenging to make the install airtight; the tails need to be movable for battery replacement.

WITH the backbox we have the slack required for movement flexibly accommodated in the box ... meaning all the entry points into the box from the loft can be sealed with a suitable intumescent.

Outcome:airtight

(I'm embarked on a massive remedial on this plasterboard tent I've acquired - would be good to hear from others with experience of achieving airtightness)

Why would you want to do this ?

 

[Octopus]

It still won't be airtight....

You're not a spark are you ..?

 

[OMGneophyte]

@Andy78, for the same reason I wouldn't put a windproof with a hole over a sweater on a cold windy day - don't want cold spots

@Murdoch, you're right - not a spark - a mortgage empoverished healthcare programmer. So enlighten me... why will it still not be airtight? Thx

 

[telectrix]

why the hell would you want it airtight?

 

[Deleted member 26818]

I hope you have no open fires in this place you want to be air tight.