Another "daughter's new flat" problem.

At present, the electrical system consists of an incoming three phase
company fusebox (one phase unconnected, one for the upstairs flat, one
for hers), thence via a Chilton voltage operated earth trip to an
isolator (fused? dunno, must check), then by a hefty T&E cable to her CU
some 7m away. The external size of the T&E is approximately 21.5mm x
10.5mm, so I take it to be 16mm^2.

There is an earth connection on the side of the company fuse, with no
obvious external connection to a Neutral, and no warning notice, so I
assume it's a TN-S system. This is connected to a couple of 16mm^2
earth wires going to the upstairs flat, plus 6mm^2 bonding to the
incoming gas (certainly) and water (I think).

There is a 4mm^2 green wire from the output end (bottom) of the earth
trip to the isolator, and one from the top of the earth trip
disappearing under the floor. This may or may not be wire which appears
at the consumer unit and is connected to its earth block, but it's not a
fat lot of use at present because it's merely resting in the hole in the
trip - not clamped at all.

The CU is an old Wylex with wired fuses, and has the novel feature of
missing bases to three of its fuse ways, giving interesting scope for
shocks, and I am minded to replace it with a new split-load unit asap.

As a first step, I propose to provide an earth cable from the isolator
(and thus I hope from the Earth of the big T&E) to the Company terminal,
thus rendering the VO earth trip redundant as an earth trip. Does this
sound sensible? 10mm^2 OK for this length? (18") or, even easier, as I
already have some, 2 parallel 6mm^2?

Please don't mention Part P. We'll perhaps worry about that later.


--
Kevin Poole
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Car Transport by Tiltbed Trailer - based near Derby