Sorry if I used the wrong terminology.

Always "Fire Foam" to me

I only assume these installs are done to the correct category and thus not an issue. If its under 800 it doesn't need covered anyway as oxo has already pointed out.

So the only time a galv box is needed is when a detector is surface mounted?

Hang on, I never said it did not need one.

Always use one. With glands.

I think this question needs to be re-clarified.

Someone has mixed up using an additional in the void as opposed to using a galv box for a thru tile fittment.

So the only time a galv box is needed is when a detector is surface mounted?

I use plastic for surface as well

I use plastic for surface as well

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.

I assumed you meant

http://www.apollo-fi...unting-box.aspx

I thought the MK trunking unit.

Must be me then, or the fact the buildings were owned by major companies and they insisted on the best.

I have only used them a handful of times, galv u box for us 99% of the time.

So the only time a galv box is needed is when a detector is surface mounted?

system device don't require metal back boxes, hence plastic interfaces, call points, panels, sounders ect....

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