In an earlier contribution to this discussion,
John Rumm wrote:


On the same theme as above you may need to bear in mind is
descrimination of the protective devices. You want to try and ensure
that a trip on the power circuit in the garrage only takes out the
local MCB and not the upstream one in the main CU as well hence
losing your lights.

Many thanks for your response.

The local MCBs are 16A for power and 6A for lighting - so, under overload
conditions, should trip prior to the 32A one at the house end. Of course, if
I cut through a wire and connect live to earth before live to neutral, the
RCD will trip and I'll lose the lights as well. I guess I have to live with
that.



That is a different cable head end from any I have seen in use in this
area, so can't give you a definitive answer. However the connection of
the (undersized!) earth connector to the side of the main cutout like
that would suggest TN-C-S.

Where does that other earth wire go that drops down from the CU? What
is that little box at the bottom of the frame?

The other earth wire goes into an adjoining cupboard which houses the gas
meter, and is clamped onto a gas pipe. The little box at the bottom is a
junction box for telephone wiring.




If coming from above, could you not have an adaptable metal box in the
loft space instead?

I *could* join it in the loft space - but that bit of loft is pretty
inaccessible, so I was trying to avoid it. What does an adaptable metal box
look like?


You could use crimps, but since it will remain accessable screw
connectors are ok. If you opt for using the screen as a CPC I would be
reluctant to have the gland connection burried in a wall behind a
metal box.

I guess I'd need a half-way decent ratchet crimping tool to use crimps -
which I don't have. I take your point about burying the gland in the wall.


Your expert advice will be much appreciated.

As usual it is worth what you paid! ;-)

If you're selective about what advice you accept, much of the advice given
here is actually worth a lot more than we pay for it!
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!