On 08/03/2018 16:44, SteveE wrote:
My 89 y/o mother can no longer reach the switch above the mirror and I
want to change it for a LED pullcord light.

The old light was installed by a bathroom fitter and was not earthed.

This light requires an earth connection but further investigation has
revealed that her upstairs lighting circuit has no earth.

Can I borrow an earth from an accessible ring-circuit in these
circumstances?

Its not a good idea to borrow conductors from other circuits.

If you must* take a feed from another circuit, then take the Line and
Neutral from there as well (via a FCU). Remember to include the earth
for the new circuit into the bathroom's equipotential bonding.

* One could argue that for a pull cord switch, where any metallic part
of the switch is out of reach, one could omit the earthing without too
much risk. Better choose a lamp fitting that is double insulated and
does not require an earth.


--
Cheers,

John.

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