Service mains extension - Installation or works

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gregmcc
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Service mains extension - Installation or works

Post by gregmcc »

The company I work for does a lot of work for a network company.

We have been asked to relocate a service pillar from one side of a driveway to the other side, about a 5m move, this part is no problem, the problem is there are currently 2 services in this pillar and they will have to be extended 5m. All the work is outside the boundary. Would the extension of the service mains be classed as works (as it's outside the boundary) or Installation? Personally it doesn't matter to me, but we just want to make sure it's one way or the other so if it ends up been classified as installation we can issue a CoC and get an inspection done.
JamieP
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Re: Service mains extension - Installation or works

Post by JamieP »

I'm not 100% confident but I think it all depends where the agreed point of supply is which may be the boundary but I also recall it can be different locations

If it's upstream of the point of supply I'd say it's works because it's not work on the installation and I'm pretty sure it's not even work on mains, it's work on exclusive fittings

I'm sure I'll be corrected if I'm wrong
AlecK
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Re: Service mains extension - Installation or works

Post by AlecK »

Jamie's right that "mains" starts at the point of supply, as defined in the Electricity Act.
Upstream of PoS there can be no "mains".
Where incoming supply crosses the boundary is the default position for PoS; and for a single installation in site is unlikely to be anywhere else.
So there's only a tiny chance this is anything other than "works".
Biner
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Re: Service mains extension - Installation or works

Post by Biner »

I know on the network where I am from they have diagrams in their standard as to where the POS are. If there is a chance of transposition of the mains cable they require it to be inspected by an authorised network inspector. This includes work done after a pole change/pillar box replacement. The question i would like to know, would any certification be needed for someone working on the works end of a mains cable before relivening?
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Re: Service mains extension - Installation or works

Post by AlecK »

Diagrams in a document like that can only be generic, will cover mist cases but not any specific special case that may exist.
but it's a step in right direction.

The "requirement" for an "inspection" is not unreasonable; given the known high incidence of polarity reversals - ALL of which are cases of failure to carry out mandatory testing.
Just to be clear, it can only be as part of the contract between network and their customer;
and it's NOT "inspection" of PEW required by ESRs.

As for work on works that can affect safety of installations, most of the certification requirements for PEW don't apply to works, nor to appliances; only to PEW on installations. However ESR 74A , clause (1AA), item (c) requires an ESC when work in fittings of works that supply any installation is the last physical connection that will allow electricity to flow in that installation.
That includes connecting / reconnecting at poletop / pillar / pit
(being pedantic; once its upstream of PoS, eg on road side of boundary, it's technically not 'mains'; 'cos "mains" is defined as being "part of an installation")
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Re: Service mains extension - Installation or works

Post by Dan L »

Surely the mains is the cables from the network connection point to the main switchboard, any alteration to this cable must be Inspected.

If this service mains is going to be extended it is directly effecting the settings of the VD/EFLI etc it was originally inspected to and must inspected again.

If it's just network side of the Network connection point or the mains not altered by just network fuse position moved then of course no inspection required.

This is my understanding and makes sense to me
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Re: Service mains extension - Installation or works

Post by Biner »

Given that no work has been done on the installation, only the works end of the cable, can we disregard the requirements of reg73 in particular 73a (e) iv, which refers to verifying a main earthing system before relivening. Not always will a lines company be able to have access inside customers houses to verify this. If the PEW has not adversely affected the installation (I.e reconnect cable), and given you have done your other checks (polarity, voltage, fault loop) to ensure that nothing has changed for the worst. This is enough to complete an ESC and leave the installation live?
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Re: Service mains extension - Installation or works

Post by AlecK »

"mains" is a defined term (ESR 4]; and is limited to the conductors that are "part of an installation".
So no, the rest of those conductors outside the boundary are - technically - not "mains".
The ONLY work that ever needs to be inspected is high risk PEW on an installation.
Since the conductors upstream of POS are part of "works" and not part of any "installation"; alterations there do not require inspection.

If a network does PEW that involves a connection (or reconnection), then the person connecting must do all those things listed in ESR 73A
Not having ready access is no excuse for omitting any of these checks. The ESRs say it must be done, so the network's duty is to arrange access so that it can be done.

The point of this particular check is that many older installations used metal water pipe , which was part of an all-metal water reticulation system; as earth electrode. That water system mostly doesn't exist any more, leaving many installations with no, or ineffective main earthing system.
Also in some areas there can be significant corrosion that can also render the earthing system ineffective.
The main earthing system is a key part of our "MEN" distribution system.
In some other countries that use various TN-C-S, the network establishes the electrode for each installations; to achieve a multiple earthed neutral and so keep the N potential close to local earth potential. In NZ - and Oz - we do this as part of the installation.
But the purpose is identical.

So not checking that the earthing system is still OK, just because it's a bit inconvenient to make access arrangements, is a rather cavalier attitude.
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