MK are to exspensive MT are cheaper but me im mega cheap and made in Rochdale:

I sometimes use these, but thought the lack of stess release is an issue ?

I sometimes use these, but thought the lack of stess release is an issue ?

The only problem with the MK type unit is the price. Surface wise we use YT2 metal insert clip (the fold over type) and these boxs. I dont bother with any clamps or retainers as the cable isnt going anywhere and its supported. We do tape the earth sleave on to the sheath in ALL events.

Same instal practice with a MCP.

How many times do you get busy on others work and pull back the trunking lid to check if they are rough ass installers?

I am guilty of spacing those fixings out £££.

lol yea me too.

Scotmod has given the impression that if a detector is fitted to a suspended ceiling tile or false ceiling(plasterboard) then it is ok to use a plastic back box if the void is less than 800mm as detection is not needed. If over 800mm then plastic is ok as a void detector would be fitted above.

Only time I fit Galv is in a harsh environment or if I'm fitting direct to concrete roofs. The trunking ones are better but too expensive. Can get boggo black boxes for pennies.

But you are correct with your second statement which is why you can use a variety of products because it doesn't really make a difference.

Only time I fit Galv is in a harsh environment or if I'm fitting direct to concrete roofs. The trunking ones are better but too expensive. Can get boggo black boxes for pennies.

But you are correct with your second statement which is why you can use a variety of products because it doesn't really make a difference.

Ok.

So to sum up a fire resistance back box is not needed to confirm with 5839 but it is considered good practice to fit one where possible?

Also on another note i went to a job last week installed by electricians where the smoke heads had been screwed to a perlin without any back box or glands. Obviously rough work but would this conform to 5839 ?

Ok.

So to sum up a fire resistance back box is not needed to confirm with 5839 but it is considered good practice to fit one where possible?

Also on another note i went to a job last week installed by electricians where the smoke heads had been screwed to a perlin without any back box or glands. Obviously rough work but would this conform to 5839 ?

RAF but unfortunately it probably does.

Ok.

So to sum up a fire resistance back box is not needed to confirm with 5839 but it is considered good practice to fit one where possible?

Also on another note i went to a job last week installed by electricians where the smoke heads had been screwed to a perlin without any back box or glands. Obviously rough work but would this conform to 5839 ?

Yep, fire resistance has to stop somewhere and the back of the detector is close enough. On your second point it's rough and probably against 7671. I wouldn't do it like that but hey ho there are some badgers out there.