Earthing from over head lines...

[infinity]

Need to do some work on a house, detatched with overhead lines supplying it.

There is a cut out in meter cupboard then tails inside the house to an RCD or ELCB, then into ccu.

There is no earth present just the tails going throught the RCD in the CU.

My question is.. How can i tell what the earthing system is supposed to be? I need to add a garage unit for solar should i earth stake it? i need to add bonding as its non existant so i could also add that to the stake earth but i dont want to add a potential difference between the earths. There is no existing stake.

Could the earth be taken from the neutral in the ccu to act as a PME type system?


Not come across this before so any help much appreciated.

 

[vernam616]

Cant beleve how many electricians rely on a internet forum to carry out their jobs correctly

 

[trev]

its supposed to be a forum not the Xfactor judging panel!

I agree. We're much more bitter, twisted, sadistic and vitriolic than them
We all get it in the neck sometimes, my turn was over an RCD test. I got far worse than this

 

[Engineer54]

Need to do some work on a house, detatched with overhead lines supplying it.

There is a cut out in meter cupboard then tails inside the house to an RCD or ELCB, then into ccu.

There is no earth present just the tails going throught the RCD in the CU.
I hope not, the only earth leakage breakers i know that has an earth connection are the old VOELB's

My question is.. How can i tell what the earthing system is supposed to be? I need to add a garage unit for solar should i earth stake it? i need to add bonding as its non existant so i could also add that to the stake earth but i dont want to add a potential difference between the earths. There is no existing stake. Yes you should install a TT earthing system for this property. You DO NOT connect bonding cables to an earth electrode!!! Both the main earthing conductor from the TT system and the bonding conductors should be taken to the installations MET. This is the only point where all earthing/bonding conductors would be connected together...

Could the earth be taken from the neutral in the ccu to act as a PME type system?
Now this is something where there is no excuse. Your actually advocating making a DNO neutral a TNC-S earthing point!!!! Totally illegal!!! ...You really do need to thoroughly go through BS7671 Reg's and the OSG's earthing sections, because contrary to what you have stated here, you do not understand earthing arrangements at all!!


Not come across this before so any help much appreciated.

The posters here are quite right in airing there views based on your OP. When i first read your OP i couldn't believe what i was reading, this is all basic stuff, there is nothing here that would cause an electrician any problem sorting out. And certainly not in the ways you are suggesting!!!

 

[alarm man]

Was only asking for advice, its supposed to be a forum not the Xfactor judging panel!

a spark..its a no from me

 

[infinity]

I agree. We're much more bitter, twisted, sadistic and vitriolic than them
We all get it in the neck sometimes, my turn was over an RCD test. I got far worse than this

Ha, well looking back it is a stupid question i deserved that! but what i had on my mind did not translate to paper, believe it or not im actually a pretty good spark, we've all asked a stupid question at some point!

 

[infinity]

a spark..its a no from me

Thanks anyway Sharon..

 

[jase]

Phone DNO and find out if they are supplying an earth, if not fit Earth rods. Not that difficult is it?

I did that once they didnt know themselves what supply they had in the street i was working in!!! pathetic

 

[Spudnik]

As a general rule, if there are two overhead lines entering a property then the earthing system should be TT.

If the overhead line is single, there is a chance that, even if the installation is still TT, PME could be available, and converted as such.

A phone call to the DNO would confirm the latter, via them doing a site visit.

 

[jase]

Had this about 3 months ago, overhead lines coming into property - 1 cable, just like pme, looking down the street every 3rd or so pole had earth cable coming down it, looking like pme, there was a 16mm earth at the cut out that went inside to the consumer unit, but not connected at either end, there was and old earth stake which was connected, so i'm thinking here we have an old TT installation, that the overhead wiring has been converted to pme but the house has not been, phoned e-on and got directed and re-directed, listened to lots of pretty music whilst "on hold" and the answer??? "we dont actually know what type of wiring we have in that area" !! jesus christ!!! suffice to say even though there could have been a lovely low pme Ze to be had, i left the installation as a TT because at least that way i could confirm the earth arrangement!!


So can sympathise with OP, cause sometimes things aint what they may seem, could be TT could be overhead pme, but obvious lack of any earth would dictate to rod it and TT it, oh and the DNO??? i dont know why people say to call them, next to useless advice in my experience

 

[alarm man]

Thanks anyway Sharon..

only on a weekend mate,im steve through the week.:ninja:

 

[Spudnik]

Had this about 3 months ago, overhead lines coming into property - 1 cable, just like pme, looking down the street every 3rd or so pole had earth cable coming down it, looking like pme, there was a 16mm earth at the cut out that went inside to the consumer unit, but not connected at either end, there was and old earth stake which was connected, so i'm thinking here we have an old TT installation, that the overhead wiring has been converted to pme but the house has not been, phoned e-on and got directed and re-directed, listened to lots of pretty music whilst "on hold" and the answer??? "we dont actually know what type of wiring we have in that area" !! jesus christ!!! suffice to say even though there could have been a lovely low pme Ze to be had, i left the installation as a TT because at least that way i could confirm the earth arrangement!!


So can sympathise with OP, cause sometimes things aint what they may seem, could be TT could be overhead pme, but obvious lack of any earth would dictate to rod it and TT it, oh and the DNO??? i dont know why people say to call them, next to useless advice in my experience

I cant help with the DNO except to say that i havent had any real issues with SSE, however, you can check for PME at the CU if you think its available.

At least that way, you have a case to try and contact someone who knows what they are talking about.

 

[nickblake]

a good majority of the supplies up here are from over head lines and they are mainly TNCS ,occaisionally TT ,this may be a silly question but have you done a Ze , I bet the RCD you are talking about is an old brown one if im not mistaken they were outlawed in a change of the regs back in 1984 or around that time as jason has said contact the DNO for advice

 

[jase]

the OP said there was no earth, how can you do a Ze with no incoming earth??

 

[Knobhead]

Blimey, the arms membership bar has been lowered!

I thought it had been raised, I’m bared!

But that aside, our OP is showing a total ignorance of basic physics. A ELCB with no earth rod?

A 10 year old house with a ELCB? I don’t think so, they weren’t on sale then!

 

[Spudnik]

the OP said there was no earth, how can you do a Ze with no incoming earth??

Do you want to have a think about that for a minute?