Network Connection of Mains

[Slovett]

Hi,

I have a question about the way Mains get connected in the WEL Network area.

The Line Mechanics have been told what they are doing is illegal by another Inspector. At this stage, I disagree with the Inspector, but thought I'd post the topic for discussion.

In the WEL Networks area, the Line Mechanic will come to site usually the day before the Meter Hanger is due. The Line Mechanic will test Mains cable at their end. Which includes an I/R test, also make sure the Main Neutral has a reference to Earth via the M.E.N link (Visual plus a test between unterminated Main Neutral at the network end the Network Neutral), a dead polarity test then Liven for testing purposes (which includes a live polarity test, voltage test, Loop impedance Test.) They then de-energise the circuit by pulling the fuse(s)) and leave them in the MeterBoard for the Meter Hanger. The Inspector will show up, do their tests, then the next day the Meter Hanger will do their job and Liven.

The Line Mechanic will NOT terminate Mains to Network if the MeterBoard etc. has NOT been terminated by the electrician. WEL Networks also require a to sight a CoC from the Electrician before they will Terminate to Network.

Im guessing The Inspector is saying it is illegal to be left like that because the Neutral is a Live conductor which is exposed at the MeterBoard via unterminated Shunt Neutral / Meter Neutral.

I can't find the reference at this stage, but I have read something along the lines that the Neutral is exempt from being treated as a 'Live' Conductor if it is directly connected to Earth. ie. via the MEN link. I'll try and find the Clause / Reg later on.

EDIT- 3000 - 1.4.63 is the clause I was looking for I think, but that exception refers to a Neutral Bar connected via M.E.N link, not so much a Neutral Conductor.

Anyway, what are your thoughts??

[Slovett]

O.K, I've just been given some more info - It's more to do with ESR 73A and the Line Mechanics terminating at the Network end potentially without sighting an RoI.

ESR 73A (1) (d) - if the work is required to be inspected, either inspect the work and complete a record of inspection or sight a record of inspection given by another person no earlier than 6 months before the installation or part installation is connected;

ESR 73A (5) To avoid doubt, in this regulation connection refers to the prescribed electrical work that is the final step that will allow electricity to flow in the installation or part installation on which other prescribed electrical work has been done.

So I guess the Inspector who says what they are doing is illegal is technically right, unless the Line Mechanics sight an RoI before they do the PEW that is the final step that allows electricity to flow.

[AlecK]

I agree that it is non-compliant to connect to supply (active or neutral) without sighting (else issuing) a CoC and also an RoI if there is high risk PEW.
It's my understanding that on many areas, the people making connections to network don't even sight a CoC.

The pre-connection testing described is also much more than happens in most areas.
However while connection-for-testing is allowed by the Act, leaving connected afterwards, with simple isolation by fuse, may well be illegal


An unterminated N conductor for meters - as described- is a live conductor once the network end of mains N is connected to supply.
But remember that the definition of 'live conductor" is not 1.4.x in "3000"; instead it's the definition in ESR4 ( as per ESR 4(2).
Which makes every N a 'live conductor".
The reason I say it only becomes one once connected to supply is that up until it's connected it doesn't actually become a neutral conductor,
it's only an intended-to-become-neutral conductor.

Noting that if the meter(s) are not yet installed there must also be an unterminated A in there as well;.
which is much worse, unless it is controlled by a meter isolating device that is locked off.
And even with a locked-off isolator; the A has still been connected to supply without sighting an RoI.

Since even basic insulation must not be accessible without use of a tool; simply fitting basic terminals on the conductor ends isn't enough.
The question becomes whether the meter enclosure is left open pending installation of the meters (giving access) or whether it's properly closed up.


Given the work sequence described; at least two CoCs and two ESCs are required.
1st CoC covers both sections of mains(upstream & downstream of meter location (and probably lots more.
1st ESC covers the mains A to meter, plus mains N to meter, and generally also to main N-bar (and anything beyond N-bar) .
- This one must be issued by the line mechanic as person connecting to supply at network
2nd CoC covers installing the metering / load control.
- Generally no RoI needed for this CoC; as installing shunt-N metering is not "mains work" and therefore not high risk PEW.
2nd ESC covers the metering, plus the mains A from meter(s) to main switch (and anything downstream of that).
That's another aspect that is widely ignored.

[Slovett]

Thanks for the reply AlecK.

So in this case, to satisfy requirements for ESR 73A would be for the Inspector to turn up first, Inspect relevant Mains Work, then send RoI w/relevant CoC(s) for the Mains Work to the Line Mechanic - and also Meter Hanger (Currently RoI w/CoC(s) only gets sent to Meter Hanger / Livening contractor)

OR the Line Mechanic removes the Phase Conductor from Network fuse after live testing, leaving that for the Meter Hanger / Livening Contractor to connect, negating the need to sight RoI

There are always Meter Isolators in the Waikato (as far as Im aware), so locking the Meter Isolator off or removing the unterminated Phase conductor from the load side of the Meter Isolator is a simple fix (as well as leaving the network fuse out) and covering the end of the unterminated Shunt Neutral as well as screwing the MeterBoard door closed and ensuring the SwitchBoard cover is on (covering Neutral conductors with basic insulation connected to Neutral Bar)

So following on from this - is it the responsibility of the Inspector to confirm Polarity of Mains? ESR 73A also puts that responsibility on to the person connecting (Line Mechanic and Meter Hanger). I would say yes, as it is the Polarity of Mains - but if the Inspector turns up first, that would be hard to achieve.

[gregmcc]

As someone who is a contractor to WEL networks I can tell you exactly how WEL want it to work.

1) WEL LM who does the network connection (they have a team that only does network connections) will only do so IF the building end is safe (WEL policy), this means service phase(s) terminated in to isolator,no tail in isolator, N lugged and bolted in place on the N-stud in the meter board, meter N end tapped up, Meter board screwed shut. The will do a power off polarity, IR, visual sight of main earth conductor. complete connections in service pillar, liven and test - polarity, voltage, loop. Unplug service fuse and leave in meter board. I have *never* seen them complete an ESC (line mechanics don't like paperwork), or sight a COC or ROI. It is common for a WEL contractor to do this process if a new service pillar is been installed and the service cable is ready and waiting.

2) Inspector comes along, this sometimes happens before step 1, does their inspector things, if the pillar end is done and they are network approved, they will liven for testing (assuming pre livening checks are good), complete the ROI, pull the fuse and leave in the meter board along with the ROI.

3) Meter person comes for their bit - if the service connection is not done - they walk away, inspection not done or cannot find the ROI left in the meter board - they walk away (sometimes they are contracted to do the inspection at the same time), can't find the COC - they walk away (any excuse and they walk away) They install meter, again the usual IR, no power polarity, then liven and test polarity, voltage, loop, check meter functioning and they then fill in the ESC for the installation. Meter installers are network approved and can open up a service pillar to liven.

my view on this is - this is ok as the LM who does the network connection doesn't complete enough for electricity to flow in to the installation - phase ends at the isolator, Neutrals are made safe and the board is closed up. (technically the N is a live conductor, but it is fully enclosed by a screwed shut meter board).

The inspector - if the network connection isn't complete a loop test cannot be completed - and often the inspector does not/is not allowed access to the network pillar to complete live tests - all that can be done is to note this on the ROI or ignore the network access requirements and liven to test.

The Meter installer - they are the ones who complete the final connection that allows power to flow in the installation - so they must complete the ESC, hard to blame them when they walk away from a job with no sign of a COC or ROI.

WEL have a reasonably robust (IMO) process (I would think other network companies have something similar), there may be are few technical issues but for the sake of making it too difficult the process works. If the LM had to disconnect the phase and Neutral at the service pillar before they left, then the inspectors had to reconnect both, test and disconnect again, then the meter hanger have to reconnect a third time - the fuse holder screws would be worn out before power actually went on for good, I can tell you from experience the meter hangers do not like having to do the connections in the service pillars.

A large amount of network faults are poor connections at the service fuses, imagine 3 chances of this happening every time a new service was installed.....

[Slovett]

Hi gregmcc,

That's a good point you bring up about Electricity not being able to flow without the Meters Connected, I've never thought of it like that, but it makes sense.

[AlecK]

Agree that under normal conditions electricity can't flow with all those precautions.
But in event of a fault in the incoming mains it'll flow extremely well.
I'm fairly confident that EWRB, or a court, would interpret 'flow" as incliding both normal and abnormal conditions.
So the fact the intended circuit is incomplete , eg by meter being absent, should not bethought of as a case of 'electricity can't flow'.

There are several issues here; main ones being safety and compliance.

Eg unterminated A conductor is a safety matter.
For that we cannot rely on simple isolation that can be altered by anyone.
Supply fuse out is better than a more accessible means of isolation.
Locked-off isolating switch is even better.

The paperwork, and especially order of doing it, and who does exactly which bits; has little to do with safety but lots to do with compliance.
The only safety aspect is the fundamental basis of the while regime; ie that there can be no electrical hazard unless / until connected to a supply.
which is why it's the ESC that's the officially recognised document for purposes of Building Act.
The person issuing an ESC is accepting full responsibility for the safety of whatever they connected.

whenever people at the sharp end suggest that the certification system set up by ESRs is impracticable in the real world;
the usual response from ES is along the lines of "stop complaining and find a way to make it work".

Some networks pay more attention to this than others; but I don't believe that there's any network that fully complies WRT the certification - inspection - connection -ESC - livening sequence that ESRs demand.
And many use their commercial monopoly to insist that the rest of the industry accept whatever bastardised system they prefer.

Such non-compliant systems / sequences may fit the "find a way to make it work" concept as long as there's no incident.
But when an incident occurs, it's the letter of the ESRs that counts.
So while we may have to accept non-compliant network processes in the interests of getting the job done;
we should be careful that what we do personally - in whichever of the many roles we may be acting in - does comply.
In particular, being very careful with descriptions of exactly what we certify / inspect / connect.

I won't comment further on the particular processes described here; except on the suggestion that connections to service fuses might need to be disconnected and reconnected several times (and I agree that this is undesirable).

Permission to connect for purposes of testing is in the Act, so can be seen as ranking higher than the process set up by ESRs.
The Act doesn't specifically state that once the testing is complete the (whatever0 must be disconnected again;
but certainly the only logical inference is that it can only be left connected of all is OK.

Seems to me that EWRB / court is likely to find that the best - and only? compliant - way of avoiding the need for multiple connections / re-connections is for the connection-to-network to happen later in the sequence.
Could be before or after meters are installed; but the risk of multiple connections only arises because they are - illegally - connecting before inspection.
There's nothing on the ESRs that requires an Inspector to do any live tests.
Same for meter installers (though the companies they work for may want a live test as-installed).

If the connection to network was made after inspection ( ie after sighting RoI , as per ESRs);
then as long as the installation was in a safe state it could be left connected even with metering not yet installed.
In fact it could even be left energised up to (locked-off)meter isolator.
connection only need happen once; and the only difference between meters present / absent would be the description on the 2 ESCs.

"find a way to make it work" may appear a somewhat flippant response from officialdom;
but i don't believe it was ever intended to mean find ways that don't actually comply.
More that we - all sectors - should forget what had become accepted practice and co-operate in achieving a result that's both safe & compliant.