PME ???

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Simannjo

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Evening all...

Last 'sparkie' left new split load consumer unit without any earth connection and 16mm earth cable sticking out of said new consumer unit! Done 2 years ago!

Can you tell from pictures if henley block on neutral can be used as PME or is customer going to have to pay new price of

 
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The picture strongly suggests a TT earthing system at present.
Would concur there PRO'

Simannjo. why do you assume PME rather than TT??

I was of the understanding that PME supply's should have a durable sign adjacent to the incoming supply with wording such as "P.M.E. SYSTEM"

cant find a reg to back this up... but I am certain all PME (TNCS) jobs I have worked on DO have a label

The fact you have two cables coming in certainly point toward a TT installation.

Have you rung the supply company? ask what they say it should be?

Absolutely under NO circumstances connect any earth to the incoming Neutral without verifying in writing that you are OK to do so?

Even so IMHO if it was PME the supply should have a accessible earth connection point without the need to split open a Henley!

my

 

Simannjo

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Aplogioes for the delay in reply.

PME terminal it is then?
was refering to it needing a PME terminal... maybe.

Property in middle of main housing estate 1 1/2 miles from Nottingham city centre.

There is no hint of ANY earthing other than main bonding, sup bonding and 16mm unattached main earth.

I am of the opinion that a PME terminal is required and wanted to make sure the henley block on the neutral wasn't already some form of PME terminal.

The degree of electrical work previously carried out suggests a known TT installation would have been completed with relevant rod.

Customer vaugley remembers being told he would have to make a phone call to DNO to sort something out, but it was 2 years ago.

 

Lee321

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if your asking if you can just add the main earth to the neutral block then i'd say no.

i think your assuming as the earth is connected to the star point of the transformer which is neutral its the same thing.

and you would be correct that only 2 conductors on pme system enter the house live and neutral and then the elec board "create" an earth point from that neutral conductor, but in that system that cable "concentric cable" is earthed to terrafirma at multiple instances on its route back to/from the transformer.

you cannot assume that your supply cable is pme.

 

steptoe

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DEFFO NOT A PME as what I can see from the pic, really looks like an olde worlde sheathed system, modern TNS, perhaps the previous spark informed tenant to call DNO to obtain PME so he wouldnt have to TT system, and also avoid having to pay DNO the required sum to upgrade to supplied earth.

looking at this the complete head would need replaced, and TBH I would very much doubt the cable would even be adequate to carry PME!

it simply looks like a dual incomer.!

I woulnt even be optimistic for a new TNS from this connection.

remember that DNO supply earth at their discretion, not as an obligation.

personally I think you would be much better, and safer simply to TT the installation and ensure your work is up to standard.

 
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How old is this house probably built in 20- 40's This looks like an old Tns system . Can you get a picture below cut out. Is that board asbestos. If so you could maybe get electric board out to a upgrade supply and remove asbestos board on h&s grounds then maybe they may even give you a Tns earth. Is the Hed below metal if so this will be earthed through cable.

batty

 
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Steptoe, as normal, is correct here, along with GF, SL and my other esteemed colleagues. I know that the DNO around here would change that HED if called out; and, as someone said, they do have a habit of enclosing the PME term. within the HED.

Why not just ram a rod in? Quicker, cheaper (

 

extension15

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Quote:

Where it is intended to use PME the distributor and the consumer must comply with the Electrical Safety, Quality and Continuity Regulations 2002.

:)

Appendix 2 BS7671

 

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