3 phase supply, advice required

[lurch]

Some advice please. . . I have a local community centre (old prefab) that has a 3 phase TNS supply from the local DNO. I have carried out a EICR which has unsatisfactory on various points, however I am trying to locate the regulation that covers isolation. . . . the scenario is 3 phases in to 3 phase meter, and then 3 separate single phase domestic Consumer units, all located within a cupboard.

My concern is that there is no single point of isolation on the 3 phase supply. I want to give this a C2 but not having come across this scenario before and want to know the regulation that covers this . . . if there is one. Or is it totally acceptable to have this setup as it is. . . . constructive answers always welcome.

 

[lurch]

It’s not potentially dangerous at all so it’s no chance a C2

I guess that is down to intrrpretation

 

[Deleted member 105166]

Digressing slightly, this is a rather decent supply for a community centre, compared to many.

 

[Dillb]

Hi Pete, I don't think it makes any difference whether its a 3 phase supply or a single phase!
A local plumber in Prestwich,Manchester turned off the consumer unit, because he was going to change the shower. What he didn't spot was a Wylex 104 in the corner of the mains cupboard. Consequently, the world is one plumber less.

As Pete mentioned he obviously didn’t follow the correct procedures, a simple voltage tester would of saved him yet he got complacent.

 

[Dillb]

Hi Pete, I don't think it makes any difference whether its a 3 phase supply or a single phase!
A local plumber in Prestwich,Manchester turned off the consumer unit, because he was going to change the shower. What he didn't spot was a Wylex 104 in the corner of the mains cupboard. Consequently, the world is one plumber less.

As Pete mentioned he obviously didn’t follow the correct procedures, a simple voltage tester would of saved him yet he got complacent.

 

[lurch]

It’s not potentially dangerous at all so it’s no chance a C2

I guess that is down to intrrpretation

 

[lurch]

I guess that is down to intrrpretation

but if there is no reg that covers it then yes C3

 

[Ian1981]

Each consumer unit has a means of isolation to their respective circuits.
I can’t see how not having a single point of isolation may result in potential danger to the user of the installation of anyone else.

 

[lurch]

Digressing slightly, this is a rather decent supply for a community centre, compared to many.

my thoughts exactly . .. however there is no gas and all water/heating is 3 kw immersions and fan units, and the cut outs at 60amp BS88s

 

[Steve Bramah]

clearly not.

Now we are moving into the realms of assuming that everyone is foolproof, just because they are a tradesman. Today's "super regs" have been drawn up, assuming that everyone that's not electrically qualified is a moron. The incident i brought up happened in the days before thins like RCDs MCBs etc, but a single point of isolation would have saved his life.

 

[lurch]

We replaced the DBs in a similar setup, fitting a 4 pole isolator marked installation main switch. This was the last job we ever used MK consumer units.
View attachment 41620

. . . hahah sounds like your view of MK is a little like mine. . . rubbish!!

 

[Ian1981]

Now we are moving into the realms of assuming that everyone is foolproof, just because they are a tradesman. Today's "super regs" have been drawn up, assuming that everyone that's not electrically qualified is a moron. The incident i brought up happened in the days before thins like RCDs MCBs etc, but a single point of isolation would have saved his life.

Suppose there was a single of isolation, what if said isolation switch was faulty and only isolated say the neutral.
Unskilled personal who do not use safe isolation and testing procedures should not be working on Electrical installations full stop.
Trained skilled personnel would only have isolated the circuit to be worked on anyway.
It’s very unfortunate and a tragedy but they should no their limits.
An isolation switch or a lack of is not to blame in this case.

 

[Steve Bramah]

Each consumer unit has a means of isolation to their respective circuits.
I can’t see how not having a single point of isolation may result in potential danger to the user of the installation of anyone else.

Hi Ian, you are assuming that the installation you are about to work on, "does exactly what it says on the tin".
In my experience, most EICRs that i have carried out have incorrectly marked boards, due to modifications and additions by "electricians" who haven't altered, or updated the legend. Especially love the one that says "sockets in bobs office". His office was demolished 5 years ago, and Bob doesn't work here anymore. Its not a perfect world we work in.

 

[Ian1981]

We replaced the DBs in a similar setup, fitting a 4 pole isolator marked installation main switch. This was the last job we ever used MK consumer units.
View attachment 41620

Cpc’s should’ve enter the same hole as the tails
The only exception is where a swa has a parallel cpc running with it and non ferrous gland plates etc.
Good job non the less tho haha

 

[Ian1981]

Hi Ian, you are assuming that the installation you are about to work on, "does exactly what it says on the tin".
In my experience, most EICRs that i have carried out have incorrectly marked boards, due to modifications and additions by "electricians" who haven't altered, or updated the legend. Especially love the one that says "sockets in bobs office". His office was demolished 5 years ago, and Bob doesn't work here anymore. Its not a perfect world we work in.

Which is why we carry out safe isolation and testing.
As an electrician if we wanted to work on bobs office sockets then we wouldn’t isolate the whole installation by switching off the main isolator would we?
In This case we would be isolating all 3 consumer units causing possible disruption to the rest of the installation.

 

[Steve Bramah]

Which is why we carry out safe isolation and testing.
As an electrician if we wanted to work on bobs office sockets then we wouldn’t isolate the whole installation by switching off the main isolator would we?
In This case we would be isolating all 3 consumer units causing possible disruption to the rest of the installation.

I think we are moving away from the point. What you have stated is correct, but the point i am trying to make is don't believe what is on the legend.