On 15/08/2016 08:30, Mike Tomlinson wrote:
En el artículo , Andy Wade spambucke
escribió:

You're supposed to test and assess each circuit before connecting it to
the new CU.

*Supposed*.

This is a group comprised mostly of amateurs with a sprinkling of
professional contributors. I wonder what proportion of us (the group
users) would test each circuit when replacing a CU? Testing would
require the use of equipment that I think most of us wouldn't have,
beyond a multimeter.

I would hope that anyone changing a CU would be able to do at least some
basic tests - even if just with a multimeter. Its going to be the
easiest time to check things like ring continuity, and making sure there
are not obvious earth to neutral shorts since you have access to each
circuits wires in isolation[1].

I know I didn't test, but connected circuits to the new CU one at a
time, powering on in between.

Even that achieved some level of diagnosis - had you connected a circuit
with an earth neutral short or particularly poor insulation resistance,
the RCD trip would have told you which circuit was a likely candidate.
Certainly better then wiring everything up in one hit and then not
knowing what was causing it to trip.

[1] The first time I did a CU swap, I bought the basic test gear s/h
from ebay for £150 (that was for standalone Insulation resistance meter
and low ohms meter, RCD tester, and Earth Loop meter). I knew that I
could always flog it again for much the same money once I was done with
it if I had wanted.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/