Lack of neutrals

[meggerlover]

Hi guys done an EICR other day 3phase 32 circuits


problem is out of the 32 circuits there was only around 10 neutral cables 3 of which was from t&e the rest in singles any ideas guys

 

[meggerlover]

Can you expand on what is in this board load wise ...do you have many lighting circuits balanced over the phases?
Are the circuits correctly identified?
Switch of the N should be avoided in favour of a solid N block, if as you suggest it is a 4pole main switch ensure the N for that model is early make late break.
Is this the primary distribution board or a down stream sub-mains?

its the primary Db and only one
6 ring mains several lighting circuits radial circuits etc the 2 neutral bars on the Db are being used for the circuits with neutrals at this Db

 

[Sintra]

Guys some of the ops replies where sitting in the moderating queue. They should all be visible now.

 

[Darkwood]

its the primary Db and only one
6 ring mains several lighting circuits radial circuits etc the 2 neutral bars on the Db are being used for the circuits with neutrals at this Db

May explain the 4 pole front end but still check its early make late break on the N.... the N is only required to be switched if this switched is a switch expected to be isolated by a member of the public hence households have to have Main N isolation as in the form of the front end DP switch.

How is the lighting operated is it switching backs of contactors via an aux' control circuit or are the lighting loads run through the switches direct?

Also other arrangement may see a balanced lighting set-up that can be found in factories where 3 lighting circuits use a common N, consider a lighting track 3phase 400v with 3 sw lines and 1 N, other measures for switching or isolation will need to be taken if this is the case and here's where a knowledge of 3ph set-ups is required, going back to your opening post the main reason you got a lot of stick is you had already carried out the testing etc then asked the question, 2 point come to mind here..

1 - if you don't understand or recognise the set-up you shouldn't commence with the testing, you admit to not understanding the lack of N with respect to the 1PH circuits so if further investigation still had you scratching your head then you shouldn't be carrying on with the testing itself.
2 - You say only live testing available ... regarding the N issue you should have informed the customer that you have concerns and require power down to confirm your suspicions if this is not an option walk away or ask on here but before your testing not after hence the back lash

 

[meggerlover]

May explain the 4 pole front end but still check its early make late break on the N.... the N is only required to be switched if this switched is a switch expected to be isolated by a member of the public hence households have to have Main N isolation as in the form of the front end DP switch.

How is the lighting operated is it switching backs of contactors via an aux' control circuit or are the lighting loads run through the switches direct?

Mall lighting is just light switches or pullcord a in bathrooms/toilets

 

[meggerlover]

Main lighting is just light switches or pullcord a in bathrooms/toilets

Main..

 

[Darkwood]

The more you drip feed the info the more it sounds suspicious and a full testing is required regardless of customers opinion, if it is all borrowed then some of the N cables could be overloaded and a shock and fire risk.... and posses a very real danger to any tradesmen especially Electricians working on isolated circuits that test dead.... then someone plugs a load in or switches a light on ....as we have no other info and it possible you have missed a key point that could explain everything then we can only throw wild guesses at you.

PS Ive added to my last post you may have missed the edit but as advice goes I can't really add any more without info.

 

[silverfox1]

What is the building this board is in used for, is it a small factory unit or commercial shop, storage facility , are there any machines.

 

[meggerlover]

What is the building this board is in used for, is it a small factory unit or commercial shop, storage facility , are there any machines.

its basically an old victorian building converted into offices for 3 seperate companies also has 2 extensions built on it

 

[Knobhead]

 

[R G]

Getting info from this thread is like being sat in hospital on drip feed over several days....


The only way I can think off in identifying what circuits have a shared neutral , assuming its the lighting ,so you would have to ensure the power circuits are not affected, is to switch on all the lights and make sure they are working , then identify what circuits feed what lights by switching off the MCBs and make note of all then again isolate all lights and isolate one of the neutrals and make safe, then switch on all lighting MCBs and again make note of what lights are not on, should if shared show possibly 2 circuits out maybe more. isolate all lighting again and repeat on the others until you have identified the shared neutrals , I can't think of an easier way at this point in time ...

 

[Badged01]

Some of the posts/replies/questions/answers etc ..... on this thread confirm my long held suspicion that its not just the domestic arena that needs some competency checks and balances but the commercial/industrial areas as well. Once let loose in that environment there really seems to be no control, unless there happens to be a competent and dilligent electrical works manager (or equivalent) who knows his stuff and is willing to reign his troops in!

Do we need an authorative and beefed up equivalent of the "Part P" police coming to factories near you soon (with a suitable HSE rep in tow) ....... alas, I no longer have to work in that environment :angel_smile:

 

[Lucien Nunes]

isolate one of the neutrals and make safe, then switch on all lighting MCBs and again make note of what lights are not on, should if shared show possibly 2 circuits out maybe more.

Does not sound like a good method if it's a TP+N board - could end up with some nasty voltages if disconnected neutral serves more than one phase!

 

[Darkwood]

Part P has messed up the domestic arena ...please don't suggest that its expanded to our fields of work it would be a disaster, there is little if any prep for working in large industry in modern courses so pointless anyway what is needed is an industrial level extension to modern courses, I worked for several yrs in the industrial sector under supervision before been allowed to inspect and test, design and install etc ... too many 'Electricians are crossing the border without realising that it a very different world and usually beyond their competence.... unless you have yrs of experience of varying install methods, machine supplies, lighting set-up etc etc then you should not be doing inspection and testing on the boards, unfortunately there is nothing at the moment to stop a Qualified Electrician without experience in this field from walking into it and doing inspections and work.. Im not talking of wiring an extra socket etc here Im talking the more involved work and design.

 

[Badged01]

My point exactly Darkwood. Unless you are in a very regulated industrial environment no-one seems to be policing the competency of 'electricians' working out there!

Think what we may of "Part P", atleast it was an attempt to try and regulate the domestic environment and ensure only 'competent' persons could work there. My personal view is that it isnt working because the levels of competency arent high enough or policed enough and it needs a total re-vamp.

I'd go as far as to say the whole electrical industry needs a good look at itself because for me JIB/NECEIC/ECA etc..... are all the same. They profess to be 'governing' bodies of different magnitudes but ultimately they are there to make money by signing up punters to their scheme

 

[Pete999]

Part P has not only up----ed the Domestic arena, it has released a backlash into the Commercial and industrial arenas as well judging by this thread, when will the scams stop playing with peoples lives, Oh sorry the lure of cash seems to have over come all decency with regards to safety, I don't mean to offend anyone but fcs lets get real

 

[Knobhead]

I’ve only known one domestic guy cross over in to heavy industrial successfully. He was supposed to shadow me for 6 months, I told the company to let him loose after a month.
He was a natural. If we had a big project on I enjoyed working with him. He was as bad tempered as me, the boss was terrified of us being together.

 

[Badged01]

Cash is king and as long as there is a profit to be made .........

 

[RogertheBodger]

Bit of a long shot here, but under the NEC in the US it was allowed, I think still is allowed, to run three single phase circuits with a shared or common neutral, think they call it an Edison circuit.
I don't know how such an arrangement could end up in Scotland but it sounds like what you've got.
Perhaps the building or the people who wired it have an american connection, maybe other countries, like Poland, use it, but if that's what you've got be very careful when working on it.

 

[davesparks]

I’ve only known one domestic guy cross over in to heavy industrial successfully. He was supposed to shadow me for 6 months, I told the company to let him loose after a month.
He was a natural. If we had a big project on I enjoyed working with him. He was as bad tempered as me, the boss was terrified of us being together.

I reckon I could have a good crack at making that transition, although I'm not strictly domestic only. And the way I feel at the moment I could happily jack it in and start afresh, follow my grandad's footsteps into the world of mines and quarries.