In article ,
John Rumm wrote:
And you're not 'expected' to use them for this purpose - they're for
mounting a standard accessory to trunking etc. Use as a spacing frame
is a secondary one.

ah, well if you use the things designed for the purpose of extending a
backbox rather than those designed for conduit, it all works much better
- the same screws just fit through the unthreaded lugs on the extender
and go into the original back box:

http://cpc.farnell.com/PL08925/elect...us0?sku=bg-818

Right - never seen those. Not that I'd be looking for them anyway. ;-)

--
*If all the world is a stage, where is the audience sitting?

Dave Plowman London SW
To e-mail, change noise into sound.