On 24/10/2013 08:26, Dave Liquorice wrote:
On Wed, 23 Oct 2013 23:20:47 +0100, Stephen wrote:

boiler & immersion

Hum, so if a leakage fault develops in the immersion (fairly common)
it trips off the heating... Remember N-E faults can trip and RCD,
though I guess the immersion switch will be DP. Still makes it harder
to work on one or the other independantly though.


apologies for the confusion. The old circuit was for an immersion. The
old boiler was fed as a spur from a ring main.

I replaced the old boiler with a combi system and did away with the
immersion cylinder.

I then repurposed the original immersion circuit to feed the new boiler.
I left the original 2.5mm2 cable T&E in place but with a 5A RCBO to feed
the combi boiler via a 3A fused spur in place of the old 13A immersion
DP neon FCU.

This way, if ever necessary, a immersion cylinder can be put back in and
a new supply run for the boiler to give separation from the new immersion.