On 20/01/2019 18:40, wrote:
On 20/01/2019 17:48, John Rumm wrote:
On 20/01/2019 14:39, wrote:
On 20/01/2019 14:28, Dave Plowman (News) wrote:
In article ,
Â*Â*Â* wrote:
I've discovered that the wiring to a light switch is in 2 core
(i.e. no
earth) so the metal back box was unearthed. Getting an earth to it
would
be a royal pain so I've removed the metal back box and plan to sink a
surface box so the back of the switch is in an insulated enclosure and
there's no chance of the screws making contact with a live wire if a
wire broke.
What's the opinion of the jury?
Any alternative solutions?

Get some plastic screws instead? If you really are that concerned. But
don't use any type of metal plate switch or dimmer that must be
earthed.


I wanted to solve the problem rather than masking it with plastic
screws that someone might replace in the future.

Are you / have you upgraded the CU with a 17th edition / all RCBO
style setup? If so, then the addition of a suitable warning label
would be adequate IMHO.

See the section on reducing risk he

http://wiki.diyfaq.org.uk/index.php/...thout_an_Earth

It's been the plan to change the CU for the last 12 months, first it was
too cold in the roof space, then I was too busy, then it was too hot,
now I'm too busy, soon it will be too cold. I need to man-up! :-)

I don't think it will be fully RCBO because there are lots of circuits
and (when I last looked) RCBOs are still quite expensive. Ref earlier
discussions, several things can be combined onto a single RCD so there
will be a mix of RCBOs and RCD+(n)MCBs.

The thrust of what I was getting at was if the lighting circuit in
question ends up with RCD protection at = 30mA trip threshold, then you
can "get away" with proper labelling and making sure no Class I switches
and luminaires are in use. Its not as "good" a solution as a re-wire,
but sometimes that is not realistic.


--
Cheers,

John.

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