PME earth intalation

[Invisible-Man]

Hi
I was given the ok to have a PME conversion from TT by the DNO, they stated that first I had to update my supplementary earthing which I have now completed. The problem I have is getting them back to complete the PME conversion, can I do it myself?

If so, I know it means removing the main fuse but is there anything that I should be aware of regarding the conversion, apart from the obvious live cutout? I would use maybe 35mm earth wire if available as they asked for 25mm from the consumer box to connector block, then 10mm to gas and water service pipes which is now done, I believe the mains coming into the property to be 35mm.

Or should I leave well alone? I would need some PME stickers as well!

 

[davy_owen_88]

You can not carry out a PME conversion yourself, nor are you allowed to remove the service fuse.

 

[EdwardCurrent]

Hi,

Definately leave this job to your DNO.

If anything should go wrong you will be in deep water (or worse) I should imagine.

Ed.

 

[Lectrician]

And if you have been asked for a 25mm main earth, this suggests a larger supply than a domestic, and hence larger main eq bonding..........not 10mm.

A standard domestic would have 25mm TAILS, 16mm MAIN EARTH, and either 10mm or 16mm bonding depending on your DNO.

 

[Invisible-Man]

And if you have been asked for a 25mm main earth, this suggests a larger supply than a domestic, and hence larger main eq bonding..........not 10mm.

A standard domestic would have 25mm TAILS, 16mm MAIN EARTH, and either 10mm or 16mm bonding depending on your DNO.

The DNO asked for 10mm main eq bonding and 25mm to consumer on site visit!

 

[Lectrician]

25mm TAILS I bet, meaning 16mm Earth

 

[Adam_151]

25mm² earth won't fit in the earth terminal on many domestic CUs, and is a stuggle to get in the PME terminal on a 100A cutout!

 

[Invisible-Man]

25mm² earth won't fit in the earth terminal on many domestic CUs, and is a stuggle to get in the PME terminal on a 100A cutout!

That's right, I had to split the earth into two terminals, you mention the struggle to get 25mm into a PME terminal of a 100A cutout, does that mean that as an electrician you have done PME conversions yourself?

 

[davy_owen_88]

Electricians do not carry out PME conversions! The DNO fit the link and then run a short length of earth cable to an earth block. Then the electrician comes along and runs his main earth to that block.

 

[Invisible-Man]

25mm TAILS I bet, meaning 16mm Earth

The tails were already in, it's the earth from the CU that he wanted 25mm!

 

[Invisible-Man]

Electricians do not carry out PME conversions! The DNO fit the link and then run a short length of earth cable to an earth block. Then the electrician comes along and runs his main earth to that block.

I gathered that, but asked as Adam had knowledge of the difficulty of fitting 25mm earth in the PME terminal of a cutout!!!

 

[davy_owen_88]

does that mean that as an electrician you have done PME conversions yourself?

Electricians do not carry out PME conversions!

I gathered that

Clearly not.

Adam pointed out the difficulty in fitting 25mm² earth cables into a PME terminal. That does not mean he carried out the PME conversion, which as I have stated, is a job for DNO's only.

Also, as Lectrician has pointed out, for a standard domestic supply, the earth cable requirement is usually 16mm² - the main reason you are going to have difficulty getting 25mm² in there.

 

[efiste2]

as far as doing a PME conversion yourself goes, dont bother mate. unless you know what youre doing, messing with live cutouts is out of the question, one wrong move could give you a really good suntan at the very least and also having to explain the damage to the DNO, if your cutout is an older type, chances are they will replace it for a new one, and then just put the N-E link across, as has been said previousley. But i cant stress enough DNO cutouts in almost all cases are fed directly from the MAIN in the street with no protection until it terminates at the local SUB, so thin carefully before taking any risks

 

[Adam_151]

Just to clarify, supply was already TNC-S, longer tails were needed, somhow ended up with 25mm gre/yell instead of 16!

If it wasn't already TNC-S it would have been a different matter altogether as the DNO have to meet certain critera before they can desinate it as PME (although if there is a terminal there and they've whacked a great big PME label over it....!), but you cant just drop an earth into the neutral side is what I'm saying!

edit: more detail

 

[Invisible-Man]

does that mean that as an electrician you have done PME conversions yourself?

Electricians do not carry out PME conversions!

I gathered that

Clearly not.

Adam pointed out the difficulty in fitting 25mm² earth cables into a PME terminal. That does not mean he carried out the PME conversion, which as I have stated, is a job for DNO's only.

Also, as Lectrician has pointed out, for a standard domestic supply, the earth cable requirement is usually 16mm² - the main reason you are going to have difficulty getting 25mm² in there.

Appreciate what you are saying but electricians are individials, you cannot class them all as one, for instance DNO's job to pull the main fuse, but how many electricians do it... Also non-electricians come to think of it!!! See my point