Is this correct??

[the_mouse]

Hi , went to look at a potential job today, client requires a consumer unit change, i was hoping to use this job for assesment but there are number of issues that need resolving before a new board can be installed. one of the problems is the nuetral for the consumer unit comes from the DNO fuse unit rather than the meter

http://i18.photobucket.com/albums/b130/the_mouse/5ff55b93.jpg

there is a neutral going into the meter but comes out and goes to a rcd shower unit. is this correct?? Is it normal to have the earth connection sealed?how would u get to it? main bonds ane main earth conductor need sorting!!

http://i18.photobucket.com/albums/b130/the_mouse/c7819bc1.jpg

 

[Andy™]

nothing wrong with neutral direct from head. providing the meter does have a neutral.

its more common in 3 phase with seperate meters to have a small CSA neutral run between meters, and a neutral connected direct to service head

as for earth connection being sealed... it happens all the time. but there are some service heads that do have a small hole to allow access to the terminal.

are you sure its PME and not a TT made PME bodge? where do the incoming feed cables come from?

 

[kme]

+1

That doesn`t look like a standard TN-C-S to me; think Andy could have point.....

The Neutral is fine; but the shower obviously isn`t...........But if you`re doing a replacement CU then you`ll be dealing with that anyway.

If it IS in fact a PME, then you`ll need to connect to the earth cables as close to the HED as possible; and contact DNO for termination within the HED.

KME

 

[the_mouse]

The feed is via overhead lines, there is no evidence of an Earth rod did ask home owner if there was one which he replied there wasnt and he has lived in the property over 30 years.

The owner has a service contract with British gas which includes electrical safety check the report says installation is ok, just the consumer unit does not meet current standards no mention of the second consumer unit spurred off the upstairs ring with 2, 32A a 16 and a 6 amp circuit which in turn feeds a third board in the garage with another three circuits!! :red card

 

[kme]

Overhead usually means TT. Combine that with the lack of PME labelling, and I`d suspect a DIY-PME. Contact DNO to clarify (n.b. what`s Ze?)

Sounds like a right hodgepodge - plus there`s no RCD protection for shower (manufacturers state this 99% of the time).

KME

 

[the_mouse]

re kme:didnt do a Ze test simply because i didnt want to cut seals in order to disconnect Earth conductor, have advised owner to contact DNO in order to have an isolator fitted, would they sort the HED out??

the shower is RCD protected its after the MCB

http://i18.photobucket.com/albums/b130/the_mouse/c6069657.jpg

which leads to another question and something ive never thought about, do rcds need to be upstream of the mcb, if so why?

 

[Andy™]

er... you could always disconnect the other end of the earth conductor to test Ze....

 

[kme]

:Applaud :Applaud:Applaud

Thanks Andy - thought I was being too vague......... :Salute

 

[Nicky Tesla]

doh

 

[the_mouse]

headbang sorry didnt explain, the main Earth terminal termination screw in the board had been snapped off and there wasnt a spare to use!, i should have said. Suppose in hindsight i could have undone the choc block (3rd pic) and tested from there.

 

[steptoe]

poor excuse,

either leave it safe and test or dont,

IMHO if there isnt a PME label then it is NOT PME,

I know some others disagree with this,

but it wouldnt be a big hassle to actually ring the supplier to find out .

please do some BASIC testing before coming on to ask a BASIC question.

 

[steptoe]

headbang sorry didnt explain, the main Earth terminal termination screw in the board had been snapped off and there wasnt a spare to use!, i should have said. Suppose in hindsight i could have undone the choc block (3rd pic) and tested from there.

or been able to double up a circuit,- SHOCK HORROR,

then cut the earthing conductor and remade it.!

 

[kme]

Can you smell it?

 

[SPECIAL LOCATION]

which leads to another question and something ive never thought about, do rcds need to be upstream of the mcb, if so why?

Think about it a bit more....

consider...

1/ plug in RCD adapters..

Or..

2/ RCD main switch in a CU..

One before one after MCBs...

as they detect the imbalance between the conductors don't matter if before or after MCB's..

But remember the RCD protection is only achieved AFTER the RCD!

:|

 

[SPECIAL LOCATION]

Can you smell it?

Is it in the kichen....

What Am I going to do?

 

[the_mouse]

or been able to double up a circuit,- SHOCK HORROR,then cut the earthing conductor and remade it.!

steptoe you are obviously a very expreienced spark and for that reason you have my upmost respect, if i could have doubled up i would have so with this in mind would it acceptable to cut the main earth conductor test Ze then splice the conductor?

I have heard of splicing protective bonds but never Main Earth conductor, I only ask to expand my understanding and knowledge/experience

mouse

 

[steptoe]

steptoe you are obviously a very expreienced spark and for that reason you have my upmost respect, if i could have doubled up i would have so with this in mind would it acceptable to cut the main earth conductor test Ze then splice the conductor?I have heard of splicing protective bonds but never Main Earth conductor, I only ask to expand my understanding and knowledge/experience

mouse

you could cut the earth conductor tight to the terminal at the MET then put it into a spare way you have made available by doubling up a CPC somewhere,

although perhaps not by the book, this is the real world where we have to make judgement calls as to what is practical and will work.

 

[Nicky Tesla]

The earth conductor sometimes has a larger terminal hole so the conductor may not fit another position without separating strands.

 

[steptoe]

The earth conductor sometimes has a larger terminal hole so the conductor may not fit another position without separating strands.

has no one heard of ISCOs.?

 

[the_mouse]

you could cut the earth conductor tight to the terminal at the MET then put it into a spare way you have made available by doubling up a CPC somewhere,although perhaps not by the book, this is the real world where we have to make judgement calls as to what is practical and will work.

That is a very good point and one that ill remember sometimes i cant see the wood for the trees, more thinking outside the box, me thinks

regards

mouse