PME connection - who's resposible.

[stilllearning]

Hi Folks

I've just moved house and would like to fit a new CU at some point in the future once I'm qualified. At the moment we have an old MEM fuse box on a TT system.

There's a PME connection available but not a Main Earth Terminal that I could connect to. i.e the main fuse would need to be pulled in order to access the PME terminal. Obviously, even when I'm qualified I won't be allowed to do this.


I've spoken to my local supplier to ask them what the procedure is for connecting a new CU to the PME. I assumed they'd want to check that the bonding has been upgraded etc and would then take a 16mm cable from the PME terminal to an MET for me to connect to but they said that this was the electricians responsibility. I then explained (again) that the main fuse would need to be pulled in order to access the PME terminal. They then said that an electrician wouldn't be allowed to remove the fuse. The conversation then went round in circles for 10 minutes before I gave up. I did ask to speak to someone in their "technical department" but they said they didn't have a technical department "as such"!

Can anyone enlighten me as to what the correct procedure is and does it bear any resemblance to what happens in reality. Am I being nieve in wanting to do things by the book?

Thanks.

 

[Softus]

One problem is that, AFAIK, nobody on the forum has managed to find a law that prohibits a subscriber (or an electrician) from pulling the main fuse. There's a tenuous possibility that cutting the seal could be deemed as criminal damage, but, again, this appears never to have been brought to court.

Clearly (to me) DNOs discourage people from pulling the fuse, and they do it by saying that it's not allowed. What they're doing is refusing permission, but in reality, if you're competent, and don't damage anything, and don't kill anyone, then they'll turn a blind eye. If you don't want to do that then you could ask the DNO to pull the fuse and connect the meter tails to a new isolator, so that you have control over the installation for when you come to replace the CU, and you could install an MET at the same time.

 

[Pensdown]

Hi Folks
There's a PME connection available but not a Main Earth Terminal that I could connect to. i.e the main fuse would need to be pulled in order to access the PME terminal. Obviously, even when I'm qualified I won't be allowed to do this.

If your existing installation is TT then it's not PME and you can't convert it. When you say there's a PME connection available what do you mean?

 

[stilllearning]

Thanks Softus and Pensdown.

Sorry for the confusion, when the existing fusebox was installed it was earthed with an earth rod; since then (about 10 yrs ago according to the neighbours) the supply was upgraded and PME was made available. I just thought that if I ever get round to installing a new CU then I may as well take advantage of the PME instead of a rod.

Even if the DNO installed an isolator, I (or someone) would still need to remove the main fuse as apparently the screws which allow access to the PME terminal are covered by part of the fuses casing.

I've got a photo of one which we were given at college as part of our course notes - if only I could figure out how to post it!

Thanks

 

[luminaire]

Is your cutout 60A or 100A? If it's 60A then I would ask them to upgrade to 100A (as you want to a shower in) and at the same time convert it to PME. And whilst they're doing it can I have an isolator fitted at the same time?

 

[Adam_151]

Like this?

Yes, to get the cover off where the earthing conductor is connected you need to slacken a screw under the fuse carrier.

Pensdown has a very important point, you can't PME a supply yourself, the network needs to have multiple earth connections (hence the name!), but if there is a clearly labled earthing terminal that the DNO have provided... (not sure these side terminals are indication enough though... do they always ues a different type of service head where the network is not PME?)

Only time I've connected into one, was to replace an existing earthing conductor that was too short, of course cutting fuse seals is bad and you shouldn't do it

 

[stilllearning]

Yes, thanks, mine is like the photo and it's labled PME EARTH but there's no 16mm earth cable leaving the box.

As I said in my original post the DNO say it's the electricians responsibility to connect the earth cable but he can't remove the fuse!! So how are you supposed to do it? Surely it's up to them to take a cable from the PME "box" to an MET for the elctrician to connect to, or am I missing something?!

Thanks

 

[Lectrician]

My DNO:

Leave 16mm earth hanging - ask them to connect. Job done. If you leave new tails hanging or connected to the old ones in henleys, they will connect these aswell.

£18 for the earth, £25 for tails and earth.

 

[securespark]

As the OP says, there are countless 1000's of TT supplies that have been PME'd already. They have a PME supply sticker on, but the terminals are inaccessible.

Staffordshire is stuffed with them!

 

[electronicsuk]

Only time I've connected into one, was to replace an existing earthing conductor that was too short, of course cutting fuse seals is bad and you shouldn't do it

Now Adam, when would you have done that? Certainly wouldn't ever catch me doing such a thing!

 

[stilllearning]

Interesting to hear Securesparks comments - as I'm based in Staffordshire!

So, just to be clear: My DNO SHOULD provide an accessible Earth Terminal for me to connect to or they SHOULD come along and connect the new CU to the PME connection? Just want to get my facts right before I contact them again.

Thanks everyone.

 

[Roo]

In our area we don't connect CU's it's the sparks job.

As for wether the cutout's PME or not I wouldn't go on the advise that your neighbours seem to think it is.

PME or SNE USUALLY get the same type of cutout in our area (henley series 1 as shown above at the mo) so if an earth block isn't provided at the side of it I'd treat it as SNE.

 

[stilllearning]

Thanks Roo. As I said it is labled PME EARTH. Would the DNO be able to confirm over the phone that it is PME or would it have to be a site visit?

 

[Roo]

Would of thought it would have to be a site visit but it's mains side of things so I don't know.

Would also of thought that if they've took the trouble to stick a sticker on they would of given it a new earth block otherwise whats the point of supplying PME if nobody can connect to the earth in the cutout (legally)?

I personally would treat it as SNE unless mains fit an earth block to it.

 

[FatGit]

When I phoned Southern Electric because the seals were missing on my meter a few months back they didn't care and said electricians removed them all the time and that they would put some more on next time the meter was read. So it seems they tollerate it - in that area at least.