Quick question: whenever I've seen DP isolation switches in consumer units
the supply wires invariably enter the switch from the top, obviously because
the busbar is connected to the bottom. However, I'm just about to add an
isolation switch between the meter and a connection block and was wondering
whether I should maintain this convention, i.e. that the meter tails are
connected to the uppermost contacts of the switch?
I only ask because the meter tails are quite short and it will determine the
position of the isolation switch enclosure.
I guess the switch might specify which are the Feed and Load terminals,
in which case I used them even if they were at the top. Nor reason
though why you couldn't feed the tails in from below and then run up
inside to the other terminals. Assuming there is enough space.
It is far better to take any steps that are necessary to do a job properly.
If this means removing the seals on the meter, then remove the seals and do
the work correctly and safely. If you're already taking the seal off the
mains fuse holder, then why not take the seal off the meter as well and
replace the tails with properly measured and tidy ones and make the job look
the way it should.
The electricity supplier will be more grateful to you, if you ask them to
check the work and allow them to make sure that the installation is safe and
secure, bot just for them, but for your own safety also. A test request is
sent easily by postcard, obtainable from any electrical wholesaler, and they
send you enough notice of appointment to be there and have them carry out,
what is only about an hours work, and then when the seals are replaced, it
at least shows that the work is up to some sort of safe standard, or it
won't get connected and sealed until it is put right.
All new builds and refurbs' must go through this procedure, so it is not an
uncommon occurance for any of the electricity suppliers.
Do the job correctly first time, and save yourself problems in the future.
Yup, more than a few posts about that in the past!
Leccy companies don't appear to give two hoots about the seals on the
company fuse being broken to do work, but are seals on the meter a different
matter? ISTR that according to some posts it seems that some meters have a
modular approach that enables you to change the load tails without breaking
Incidentally, a quick look at my meter tails reveals that although the tails
between the fuse and meter are coloured black and red the meter tails are
both grey - only being identified with a 1" bit of coloured electricians
tape wrapped around them. Is this acceptable? I'm planning to change the
CU soon, and will use the opportunity to chnage the tails for properly
coloured ones if the current grey ones are not compliant.
email me at
richard at olifant d-ot co do-t uk
Common experience is that the supplier doesn't fuss about the seals on
the *main fuse* being broken - safety gains of doing so when replacing
a CU far outweigh chance of objection from supplier. (Anyone tapping in
to their supply through the fuse carrier is a prime candidate for a
Darwin award, right? No, I won't repeat the allegedly-true story of a
colleague in his roadie days performing an impromptu in-situ copper-weld
to connect up the lighting rig to the main supply panel at a continental
gig location wot had no convenient place to make a Proper connection and
the minutes to first soundcheck ticking away...) Supply companies are a lot
*less* relaxed about the meter seals themselves, as breaking that seal
allows a "safer" bypass of the meter (an illicit use for a Henley block!)
and possible fiddling with the meter adjustment. Thus-and-therefore,
many of us d-i-y'ers are reluctant to fool with the meter tails, even
though they indeed belong to us...
But we mean the seals on the terminal cover, not the seals on the actual
meter. The terminal cover is meant to be removed if you're working on the
consumer side of the supply, so it is normal to remove the seals of the
terminal cover if you're replacing the tails to a new consumer unit, say.
If you were to remove the manufacturers seals on the working part of the
meter, then you're in line for some sort of "being illegal" action.
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