Diy pme

[Midwest]

Have a job to for a domestic CU change. When I quoted, I noted an unuasual supply. It had a 3 phase supply (one phase being used), with lead sheath cable, from which was an earth cable to an MET. Also it had an earth rod with a earth cable to the same MET. Whilst doing my pre tests on the existing circuits I got PFC readings of 0.10ohm & 2.23ka on the lead sheath, and 112ohm & 2a on the rod (PSC was 0.08ohm & 2.75ka).

No documentation or notes from previous owner (new house owners moving in). Thinking the TN-S might be unstable, I rang my local DNO depot, to see if they knew of any issues in the area. I've done some work a few doors down, and they had TN-S supply.

Spoke to one of their engineers, and said obviously don't keep records for individual properties. He suggested keeping the lead sheath as means of earthing, but could consider converting to PME. I asked how much, he said nothing, you can even do it yourself.

Bit surprised, he said he would call and have a look. Which he did, and said I could use existing lead sheath earth into MET, and optionally add a 16mm from neutral of service head (as per normal PME supplies) into same MET. I asked if they didn't have to do anything else, and indeed shouldn't they
be doing this. He said nothing else needed to be done to convert to PME, and if I wanted the DNO to carry out the work, they would, but would have to wait a few weeks for an engineer, so why not do it yourself (DIY PME!).

Think I'm going to just use the sheath, ditch the rod and get house owner to consider conversion to PME.

Have anyone come across this before?

 

[Richard Burns]

Surprising advising you to modify their equipment that is (apparently) an offence to interfere with.
Presumably they are aware of the cabling supplying that area and it is of sufficient standard to be converted to PME.

 

[telectrix]

a few houses round here have TN-S with a rod as well. all been there for years. maybe the installer was concerned that DNO might, at a later date, convert the incoming supply cable to plastic. :bigcry:

 

[ferg]

Cant have plastic cables Tel.

They will go on fire.

 

[7029 dave]

Have a job to for a domestic CU change. When I quoted, I noted an unuasual supply. It had a 3 phase supply (one phase being used), with lead sheath cable, from which was an earth cable to an MET. Also it had an earth rod with a earth cable to the same MET. Whilst doing my pre tests on the existing circuits I got PFC readings of 0.10ohm & 2.23ka on the lead sheath, and 112ohm & 2a on the rod (PSC was 0.08ohm & 2.75ka).

No documentation or notes from previous owner (new house owners moving in). Thinking the TN-S might be unstable, I rang my local DNO depot, to see if they knew of any issues in the area. I've done some work a few doors down, and they had TN-S supply.

Spoke to one of their engineers, and said obviously don't keep records for individual properties. He suggested keeping the lead sheath as means of earthing, but could consider converting to PME. I asked how much, he said nothing, you can even do it yourself.

Bit surprised, he said he would call and have a look. Which he did, and said I could use existing lead sheath earth into MET, and optionally add a 16mm from neutral of service head (as per normal PME supplies) into same MET. I asked if they didn't have to do anything else, and indeed shouldn't they
be doing this. He said nothing else needed to be done to convert to PME, and if I wanted the DNO to carry out the work, they would, but would have to wait a few weeks for an engineer, so why not do it yourself (DIY PME!).

Think I'm going to just use the sheath, ditch the rod and get house owner to consider conversion to PME.

Have anyone come across this before?

Now that would be a

 

[stevethesparks]

Now that would be a .................................

The suspense is killing me :icon12:

 

[Midwest]

Can't knock the guy for his help, came round to the property straight away to have a look, hence why I posted here. Just seems a bit unusual to say the least.

I plan to use the TN-S, and ditch the rod (it's not a good reading anyway).

And Dave, I'm intrigued by your post as well?

 

[Midwest]

Surprising advising you to modify their equipment that is (apparently) an offence to interfere with.
Presumably they are aware of the cabling supplying that area and it is of sufficient standard to be converted to PME.

Yes, I get a bit jumpy pulling their fuses for CU changes, even though I have their permission and temporary replacement seals.

The engineer said there was no certainty that the lead sheath cable coming into the property, hadn't been replace with a plastic PME cable outside in the road. He said whenever a cable goes faulty, it is replaced with the plastic PME. I worked on a newish house just a bit further down, which had a PME supply.