Re: electric power shower

message from Martin Angove on 10 May 2004

[top-posting removed for ease of reading]

Sneaky, but well spotted; it's there in the wording. You are absolutely
right, neither the OSG nor BS7671 make it mandatory for either a water
heater or a shower pump to be RCD protected if they are designed for use
in zone 1.

I suspect that this common belief is another case of John Whitfield-ism:

(The Electrician's Guide to the 16th Edition etc... Revised 6th edition,
page 134)

"Water heaters and shower pumps may be installed in Zones 1 and 2, as
may other equipments suitable for the conditions, provided that they
have the required protection against water and are protected by an RCD
with a rating of not more than 30mA."

Note how the use of the comma-separated phrase "as may..." makes it a
requirement that everything must be RCD protected. In BS7671 and the OSG
this information is set out as a numbered or tabulated list and it is
obvious that the RCD requirement only applies to one item on that list.
I suspect therefore that Whitfield's assertion that an RCD is required
is due mainly to dodgy grammar.

On the other hand, there's no harm in RCD-ing the shower either...

Hwyl!

M.

Archived message: Re: electric power shower (UK DIY Home Repairs)