Subject says most of it ;-)

Just had described to me what sounds like a 60A submain to an old
rewireable fuse CU. It will need splitting to feed a new mini CU for a
9.5kW shower.

I have not seen the setup yet, so I don't know how the incoming submain
to the CU is wired, but there is a fair chance that it is not wired in
tails but either T&E or SWA instead. Assuming this is the case, which
way do you favour splitting it? 60A JB, Adaptable box, Henley and
separate earth terminal, or straight from the incomer terminals on the
first CUs main switch (assuming there is space)?


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
John Rumm writes:
Subject says most of it ;-)

Just had described to me what sounds like a 60A submain to an old
rewireable fuse CU. It will need splitting to feed a new mini CU for a
9.5kW shower.

I have not seen the setup yet, so I don't know how the incoming submain
to the CU is wired, but there is a fair chance that it is not wired in
tails but either T&E or SWA instead. Assuming this is the case, which
way do you favour splitting it? 60A JB, Adaptable box, Henley and
separate earth terminal, or straight from the incomer terminals on the
first CUs main switch (assuming there is space)?

If it feeds an old rewirable fusebox, take the opportunity to
replace the fusebox with a modern one which is big enough for
the new circuit. Note that 9.5kW will be using 2/3rds of the
60A submain's capacity -- you will need to check for loadings
imposted by existing circuits, and the load the extra 40A is
going to put on the upstream consumer unit (if it comes through
one) and the upstream supply main.

--
Andrew Gabriel

Andrew Gabriel wrote:

If it feeds an old rewirable fusebox, take the opportunity to
replace the fusebox with a modern one which is big enough for

Tis one option (and the way I would do it if it were mine), but I am
expecting that the quickest low cost option is going to be the favoured
approach ;-)

the new circuit. Note that 9.5kW will be using 2/3rds of the
60A submain's capacity -- you will need to check for loadings
imposted by existing circuits, and the load the extra 40A is
going to put on the upstream consumer unit (if it comes through
one) and the upstream supply main.

Its a commercial premisis with three phase in as the main supply. I have
seen that part of it in passing, and it did look like it had been quite
recently updated. I doubt there will be any problem with upstream
capacity. The current sub CU only has four circuits on it IIUC, so with
luck nothing too heavy.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/