DIYbanter - View Single Post - Fitting a Wylex Consumer unit with spur to shed

wrote:
I am looking to replace my consumer unit with a split load Wylex 12
way Consumer unit, since i have run out of ways on my exisiting
consumer unit. At the same time I want to run a spur to a shed for a
small ring main and lights. The shed will have my old consumer unit
(Which has a 63A/30mA Incomer providing RCD and Isolator
functionality)
Exactly what I have..
Is it acceptable/possible to connect the spur to the shed via an RCBO,
or a second dual pole isolator or should I just use a standard MCB?
I just used an mcb so the cable to my detached garage is protected.

Also what rating would be suitable for running a spur to a shed, would
a 16A MCB/RCBO be suitable? (Internaly I was going to use 2.5mm t&e
ring main cable, while externaly I was going to use 2.5mm armoured
t&e)
Should be fine, you could use a higher rated mcb if you required more power
in the shed.
I put my ext supply on a 16A mcb on the non-RCD side
I guess it could depend on how your ext cable is run. Mine is buried under a
concrete path and so I'm unlikely to hit with a garden tool.

My worries are that if there are problems on the external wiring for
any reason, then there are safety issues by just connecting it via a
standard MCB?

As a slightly seperate point does anyone know if it possible to add a
second RCD to a wylex unit, so as to provide aditional seperate RCD
protection for the lighting circuits from the ring mains?
Why? Its unusual to RCD protect lighting circuits these days..
Presumably because its very difficult to get a shock from fixed light
fittings unless you try really hard :-)
You don't have to work on them live because with their mcb(s) off you can
provide light from a power circuit.

It should be possible but you may have to cut the provided busbar. Note RCDs
are 2 mcb widths and the Wylex prebuilt kit only has 2 separate spare mcb
positions, so it wouldn't fit anyway without rebuilding the kit in a
different way.

Note if you want to get an extra mcb for the Wylex and you want it to use
their busbar, then be sure the new mcb is also Wylex brand.