ESC demarcation point

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JamieP
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ESC demarcation point

Post by JamieP »

I understand an ESC is completed for all work when connection is completed but I'm just curious on views on how much this makes us responsible for in some cases

Disconnection and reconnecting an appliance or fitting is usually easy being on the end of the supply but I'm curious about situations such as a disconnection and reconnection at a switchboard or such that happens in a switchboard replacement

Because all circuits a physically disconnected and reconnected in the process

When I write the ESC am I saying simply that what I have done and replaced is suitable for connection to supply or because I've disconnected such items in the process does my ESC also extend to cover all of the final subcircuits or submains that I am reconnecting?

I understand the concept of ESR113 and allowing things to remain but I'm just curious if anything changes because I'm disconnecting and reconnecting to supply and in doing so so I need to confirm each subcircuit is not electrically unsafe so that it can be reconnected? Or am I simply doing an ESC for the fittings in the switchboard I'm replacing? And the down stream items are not for me to recertify?

Hopefully this makes sense
TPower
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Re: ESC demarcation point

Post by TPower »

I believe technically your ESC is covering the FSCs within the installation when you replace a switchboard, but surely there has to be some flexibility in terms of what you’re responsible for?

I guess you are making changes to the FSCs when you are disconnecting & reconnecting them. If a fault in a FSC were to arise as a result of your work in the switchboard, you’d be responsible. If a fault occurred related to something pre-existing, that would’ve happened regardless as to whether or not the switchboard was replaced, I think it’d be a pretty tough call for you to be held responsible.

Seems to open a messy can of worms, would you open up every fitting to test & inspect? Inspect all the wiring etc? I’m not sure what’s right, but it just sounds a bit unrealistic to me.

If you followed the same logic you could also apply it to line mechanics, when they disconnect/reconnect service mains. Pretty sure they’re required to complete an ESC for this? Certainly not realistic that they go check every FSC. They’d still need to do the tests/checks as per ESR73A, but think this would only relate to the mains they’re working on?
JamieP
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Re: ESC demarcation point

Post by JamieP »

Yeah totally man, and I definitely understand the legal vs real world thing but it's just something that got me thinking and curious around others thought around what the words actually say and technically require rather than what is actually practical to achieve etcetc
TPower
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Re: ESC demarcation point

Post by TPower »

I guess the other thought is; when you’re connecting new work, you’re able to rely on the veracity of someone else’s COC.

Perhaps you could apply this similar principle to disconnecting/reconnecting existing. Whilst you don’t have a COC, the fact it’s connected (prior to you beginning your work) should allow you to assume that it had been tested/certified etc previously? So the responsibility of FSCs etc, still largely lies with who initially certified the work?
AlecK
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Re: ESC demarcation point

Post by AlecK »

All ESCs must include a statement as to whether the ESC applies to the entire installation, or only to specified part(s) of it [ ESR 74A (3)(b)].
So what's covered by the ESC is whatever is declared in this statement.

The basis of an ESC is set out in clause (1):
a) the part-installation us safe to use; on grounds of being electrically safe and complies with ESRs, and
b) the work has not adversely affected any other part of the installation.
These two aspects simply reflect the requirements for doing PEW set by ESR 13(1).

If all you did was replace a fitting, then that fitting needs to be clearly described as the "part installation" worked on.
So you can limit your liability simply taking care about how you fill in the certificate.

In many cases the item worked on will have other parts of the installation downstream of it;
whether that be (almost) an entire installation for a mains entry box or main switch,
or just the part of a final subcircuit that is downstream of the fitting (switch / socket / whatever) you worked on.

But unless you are connecting then to supply for the first time, you are not taking responsibility for these downstream aspects under item (a); but instead simply , as per item b), that they have not been made any less safe by what you did.

Where what is being connected is covered by a CoC (and , if relevant, an RoI); then the person connecting has to sight these documents [ESR 73A].
And ESR 73A(4) says that a person connecting can rely on such documents.
However despite the fact that a CoC can be relied on (for whatever is described as the work done);
that doesn't extend to the CoC being acceptable evidence of testing having been carried out.
Clause (3) requires the person connecting to sight signed test results; unless they did that testing themselves.
And, regardless of any other factors, the person connecting must do the basic safety checks in 73A (e) before actually connecting.

Keep in mind the various levels of electrical safety that apply in different circumstances.
The required level for new work, and for maintenance, is "electrically safe" [ESRs 13 & 74A (1)(a)].
So the item(s) you work on must be at that level.
Other items downstream that are disconnected & reconnected in the process are not required to be brought up to "electrically safe";
they only need to be "safe to connect" [ESR 73A (a)], and not adversely affected by the work done [ESR 74A(1)(b)].

The requirement to be satisfied that what is about to be connected is "safe to connect" is independent of any CoC that may apply to some or all of what is being connected / re-connected.

----------------
For the case of a line mechanic disconnecting & reconnecting mains, yes this requires an ESC.
ESR 74A (1AA) (c) was specifically added to require the ESC even when the fittings worked on are not part if any installation. As is often the case for not only the supply fuse, but also the conductors between network and PoS at boundary.

And yes there's an entire installation that's being re-connected to supply; but what's required depends on whether any PEW was done on the installation while it was disconnected. ESR 73A only applies where there has been PEW on an installation.

Eg replacing mains, there will be PEW on the installation, so ESR 73A applies.
Including the checks & tests in clause (1)(e); which while not requiring every subcircuit to be checked do go beyond just the fittings worked on - eg include confirming the existence of a main earthing system.

But a simple replacement of supply fuse or neutral connection upstream of PoS; no PEW on the installation so ESR 73A does not apply.
Just an ESC.
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JamieP (Sat Apr 23, 2022 1:57 pm) • Slovett (Tue May 03, 2022 4:56 pm)
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JamieP
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Re: ESC demarcation point

Post by JamieP »

Thanks Alec, very helpful as always
Slovett
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Re: ESC demarcation point

Post by Slovett »

I've got another question that hopefully fits in with this thread -

My local council Building Inspectors have recently been asking for a copy of the ESC (as well as the CoC and RoI) as part of their Building Consent Cert. on new Houses. My question is - who is responsible for issuing the ESC? (the Electrician who wired the house, Lines Mechanic who connected the Mains or Meter Installer who ultimately completes the PEW by connecting the Installation to a power source?) In the WEL Network area, the process to get the power on is - The WEL Network line Mechanic terminates the Mains to the Supply Fuse's (leaving the fuse cartridge out) then usually the next day the Meter Installer turns up and Installs the Meter and after satisfying 73A will then liven the Installation.
In my view the Person livening the Installation, which in most cases is the Meter Installer, is now responsible for issuing the ESC for the Installation. By completing the PEW by livening the Installation or Part Installation (74A (2)). I asked the question with various Electrical Workers a few times and they all have different answers.

Also - Does the Line Mechanic need to issue an ESC if they are only terminating Mains to the Network Supply fuse's? (Only temporarily energising Mains (not the Installation) for testing purposes)

I've never really thought about it before, but I would guess that the person issuing the ESC for a new house connection can rely on the Electricians CoC and Inspectors RoI for evidence to satisfy 74A (1)(a) and 74A (5). If not, it seems like a heavy burden for someone who's only there to install a Revenue Meter and in most cases, won't have access to the Main SwitchBoard if the MeterBoard is external and the house is locked up and won't have a clue if the PEW within the Installation complies with the Building Code
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Re: ESC demarcation point

Post by TPower »

I’m not sure that a LM should be connecting mains to the network, unless mains and metering is all complete.

Although I know in reality it tends to happen as you say, they connect and leave the fuse out for the inspector/meter installer to fit.

As mentioned in ESR74A the work is complete when it’s connected to a power supply, and an ESC is issued when the work is complete. So I think the LM should issue the ESC if they’re connecting to the network, just because the fuse-link may be left out it’s still technically ‘connected’. If a LM is connecting mains when metering and mains aren’t complete, they may be in breach of ESR73A?

I come across this a bit, it’s only an issue for me with OH lines. If it’s UG I connect to the network myself, fit metering, inspect and complete ROI, COC (for metering) & ESC. But definitely come across a few sites with OH lines where the LM has already connected prior to metering, inspection etc, like I say I’m not sure it’s technically correct that they do this?
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gregmcc
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Re: ESC demarcation point

Post by gregmcc »

the person who does the last connection that allows electricity to flow thru the installation should be doing the ESC, in this case the meter installer, without the meter no flow of electricity. As far as the LM connecting the network end, as far WEL goes, if the other end is terminated in the meter board isolator then connect the network end, but leave the fuse out and the installation safe. It is common practice for WEL to complete network connections prior to meters going on, the meter installers WILL NOT install the meter if network connection/COC/ROI is not available as they are required to test the meter before they leave.
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Re: ESC demarcation point

Post by TPower »

When you refer to ‘connection being the final step that allows current to flow’, I see this is written in ESR73A(5), and this definition for ‘connection’ applies to that particular regulation.

I’m wondering whether you can apply this same definition for ‘connection’ to ESR74A, when it comes to issuing an ESC?

If not; WRT a LM connecting to the network before metering is fitted, they may still need to complete an ESC? I mean the LM is still livening up to the metering point?
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Re: ESC demarcation point

Post by Slovett »

Yes thats true. WEL Networks will only terminate Mains if the Mains are terminated at the MeterBoard Isolator.

As far as I know, WEL Networks don't let anyone else enter their Pillars to do new Mains terminations - Meter Hangers have permission to pull and insert fuse's. And if the Mains aren't terminated when the Meter Hanger arrives, they turn around and leave.

In regards to the Line Mechanic. They don't leave the Mains Live. They only Liven for a Loop Test at the MeterBoard Isolator and to test Polarity. Then pull the fuse. The Meter Installer will then Liven the Installation once they have finished installing the Meter.

So because the Line Mechanic isn't Livening the Installation, (In my view) they aren't completing the PEW (As per 74A (2)
- For the purposes of subclause (1), if an installation or part installation was disconnected from a power supply while the prescribed electrical work was done, the work is complete only once the installation or part installation is connected or reconnected to a power supply.)

So in my view (Im probably wrong) the LM shouldn't need to issue an ESC in this case. (But should be issuing a CoC for the termination of the Mains into the Pillar / Pole?)
TPower
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Re: ESC demarcation point

Post by TPower »

Yeah, tricky one.

IMO the LM should complete an ESC in these situations, as they’re still completing the PEW to liven up to your meter isolator. Just because they leave the fuse removed is immaterial, inserting/removal of a fuse link isn’t classified as PEW.

Not sure whether they need to complete a COC though? As they’re likely connecting within the boundary of ‘works’ rather than ‘installation’.

As long as someone is signing an ESC for the work that’s connected I guess is the main thing.
AlecK
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Re: ESC demarcation point

Post by AlecK »

Correct that the key for ESCs is not "livening" but simply "connecting"; and ESR 74A was specifically changed to make clear that this includes making connections on Works [ clause (1AA) (c) refers].

Leaving the fuse out makes NO difference, the active is still 'connected' for purposes of ESR 74A.
And the neutral is also connected - and remember it's a "live conductor".
Point being if they get polarity wrong, leaving the fuse out doesn't avoid a hazardous live situation.

So yes an ESC is definitely required.
But no CoC; because CoCs are only required for PEW "on an installation", not for work upstream of the POS.
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