Hi,

about to add new circuits and need extra circuit breakers.

Screwfix lists type B and C (what happened to Type A)?

Both are shown as ISO rail fitting.

So:

will almost any circuit breaker fit any consumer unit (CU was replaced six
years ago) because they are an ISO standard fitting, or is it a case of
loads of different fittings?

Consumer unit is Siemens Stratus 200
Breakers are all marked 5sx21
Ratings are B32 or B6 (so presumably a 'B' type breaker).

See http://www.siemens-industry.co.uk/ne...rel.asp?ID=118 - apparently
they are miniature circuit breakers.

See http://www.siemens-industry.co.uk/di...n/alpha200.asp - RCCB,
switch, or split load.

Now I am more confused instead of less.

http://www.chelsworth-lodge.nildram....s/DSC00113.JPG
http://www.chelsworth-lodge.nildram....s/DSC00114.JPG


These show my incoming power and the consumer unit.

I have (it looks like) two switches for incoming power (LHS), plus an RCCD
(RHS).

How do I tell if this is all on the RCCD, or if the lighting (LHS) is
switched - which I would presume is a split load (from reading the FAQ).
It looks like a split load setup.
Is the cut in the busbar easily visible?

This brings me on to connecting in the new wiring (13 amp ring main and
immersion heater on a direct circuit).

As I seem to have two switches on the main switch, I presume one is for the
lighting side, and one for the power via the RCCD.
So I presume that I could keep the lighting running with the power side off
whilst I connect in the new cables.

(1) I turn off the main switch on the consumer unit - darkness reigns.
(2) Remove the cover
(3) Turn on the lighting side again so I can see what I am doing without
using a torch.
(4) Pull the RCCB for extra safety?
(5) Connect in the new wires
(6) Add the new mini-RCBs
(7) Power up power side (RCCD back in) with cover off and extreme care then
test the new circuits.
(8) Power everything off again and re-install the cover.
(9) Power up and celebrate.
(10) Go round resetting all the clocks, CH timers etc.

Any advice much appreciated - main issue is 'do the type B RCDs from
Screwfix fit these units - answer please in time to place the order today
:-)

TIA
Dave R

P.S.
Included the picture of the power side because I seem to have three blocks
on the inbound side - one is used for the meter and two spares.
I know there used to be storage heaters - unused sockets in the wall and a
very nasty charred CU in the garage before we had all this replaced - so
that would explain one extra service, but what was the other one for?
Is it usual to have the incoming service split into 3?
A relic of the old multiple fuse box setup?
I note there is no isolating switch between power in and the CU - would this
be a good idea or is the switch on the input side of the CU adequate?