will piggy backing earth rods to a TNS bring the ze down?

[Des 56]

Nick

DNO said to keep it!

In your earlier post you said "Told me I best rod(s) it to bring it down"

They seem to consider it to be a Tns on the one hand and on the other hand, inadequate by suggesting bringing it down
We all know that there are various methods .earth plates,tapes,old water pipes (under the householders control) etc for TT

The existing earth is inadequate,it is not under yours or the customers control (I suggest it should be under your control unless its a garenteed suppliers earth)it is not adequate as far as the supplier is concerned
I repeat what I said earlier.if its changed and or lost they wont tell anyone

 

[LlandrilloSpark]

Nick - I didn't do it, it's how I found it, I called the DNO out to see if they could verify that it was their work, he said no but happy with it.

Spin - that's the opinion I was looking for, I will just add a rod I think to cover myself

 

[Spazz]

Never mind treating it as a TT why did the DNO not convert it to a TNCS ? or did I miss something here

They will never convert to TNC-S unless the reading is under 0.35 ohms. As the reading is over 2 ohms it is not suitable for TN-S or TNC-S so the DNO cant take responsibility for providing an earth because they can't met the requirement so they hand the responsibility to the home owner to provide an earth who asks the electrician to install an Earth Rod.


Personally I would remove the clamp unless I have it in writing - I dont doubt you had verbal permission to leave it in place but the person who came out is just an electrician and not someone who can give that consent nor would he hold his hand up in court and say yes I told him to leave it there if his job was on the line.

If you leave it there make sure it has the correct label on it and you note it on the certificate under the other for bonding.

 

[ExArmy]

The regs state that only one type of earth system to be installed how can you have a TT and TN-S at the same time - you cant!

I have come accross several properties now that were TT, and have been upgraded to PME but the earth rod is still connected. is there something in the regs to say that the old earth rod should be disconnected? infact just this week I was doing an EICR on a house that had 2 old earth rods, (old guy said that 20 years ago he needed the second one installed) but they were not connected to the MET, and i actually connected them upto the MET, though i might aswell, seeing as it's protective multiple earth! surely this cannot be against the regs

 

[oldtimer]

Personally I would remove the clamp unless I have it in writing - I dont doubt you had verbal permission to leave it in place but the person who came out is just an electrician and not someone who can give that consent nor would he hold his hand up in court and say yes I told him to leave it there if his job was on the line.

Well I would not remove it as its 2 ohms do you think a rod would do better also more information what was the PFC and PSSC please

 

[Adam]

The regs state that only one type of earth system to be installed how can you have a TT and TN-S at the same time - you cant!!

Really?

What about my outbuilding that has not had the earth exported from my house?

My house is TN-C-S and my outbuilding is TT. It is acceptable to have both earthing systems in one installation.

 

[1shortcircuit]

Wow this is an interesting but somewhat confusing discussion.

As I read it... DNO inspect current TNS earthing system and confirm it is NOT theirs BUT the engineer inspecting it is happy with it but also advised you to rod it?

This advice does not make sense, if they were happy with the connection then why rod it?

If it were me in this situation I would contact the DNO and ask for a written instruction confirming which part of their advice they would like to stand by. Present that to the client after taking a copy for yourself. This copy may well be needed at a later date if the advice to Rod the installation is ignored.

:thumbsup

 

[LlandrilloSpark]

Bang on short circuit....exactly what has happened , hence I don't know what the hell to do!

 

[LlandrilloSpark]

Ok then .........

Is it acceptable to just leave it?, I've RCD the entire property including 3 distribution circuits

Ze is 2.08

Zs of circuits I've worked on comply with bs7671

 

[oldtimer]

yep shortcircuit does not smell right me thinks the DNO is covering his --- by saying put a rod in plus the OP not having a pop but you need to give more info ie Ze,PSC,PSSC rural city even ask check the guy next door because we are now in the speculation zone

 

[LlandrilloSpark]

Location.....1/4 mile from the beach front!

 

[1shortcircuit]

Is it acceptable to just leave it?, I've RCD the entire property including 3 distribution circuits

No not in my opinion, whilst you have been informed by the engineer that they are happy with the connection they have also told you to rod it. The only way you can leave it is if they give you a written instruction stating that they are happy with the connection.

The thing that you don't know is that the engineer has probably put on his report "advised electrician to install earth rod"

 

[trev]

They will never convert to TNC-S unless the reading is under 0.35 ohms

Utter, utter nonsense. I've seen TTs with readings far higher than this converted to TN-C-S, admittedly it takes a bit of work but I've seen it happen

As I read it... DNO inspect current TNS earthing system and confirm it is NOT theirs BUT the engineer inspecting it is happy with it but also advised you to rod it?

This advice does not make sense, if they were happy with the connection then why rod it?

My take on this is the DNO guy was probably ok with it but don't forget he's just the guy on the ground who is told to go there and do that. His opinion probably counts for nothing in the grand scheme of things.

 

[trev]

No not in my opinion, whilst you have been informed by the engineer that they are happy with the connection they have also told you to rod it. The only way you can leave it is if they give you a written instruction stating that they are happy with the connection.

The thing that you don't know is that the engineer has probably put on his report "advised electrician to install earth rod"

THEY as in the DNO have said nowt mate. A spark who probably has a bit of common sense has come out and said it's probably ok but what would THEIR official line be I wonder?

 

[oldtimer]

Trev just to correct you I tried to quote Nicholas who said disconnect the earth if you look at my mail below I agree with you ie leave it because will you get a rod to do any better

 

[oldtimer]

Personally I would remove the clamp unless I have it in writing - I dont doubt you had verbal permission to leave it in place but the person who came out is just an electrician and not someone who can give that consent nor would he hold his hand up in court and say yes I told him to leave it there if his job was on the line.
Oldtimer reply
Well I would not remove it as its 2 ohms do you think a rod would do better also more information what was the PFC and PSSC please

there you go

 

[1shortcircuit]

So we have established that the engineer has confirmed it is NOT an earth connection supplied by the DNO. That means the DNO have no duty to maintain that connection so the risk exists for the property to at some point, lose the earth connection?

I think you really need to cover your arse on this one. If you are going to leave it then you need to do so on the DNO's written instruction. They won't give you this. I have had only a very few dealings with the DNO and to say they are useless is an understatement (perhaps I've been unlucky and they actually really do a fantastic job)?

The engineer also advised to rod it.

In my opinion you need to rod it and if that means having to do it in your own time and accept additional cost to you then I believe that is a sacrifice you may just have to make because you have carried out alterations/additions and are now responsible for this part of the installation.

I'm so glad that I have 3 TT installations coming up in the next few weeks, all rods buried beneath the floor boards and not accessible for inspection/maintenance

Good Luck :thumbsup

 

[trev]

Trev just to correct you I tried to quote Nicholas who said disconnect the earth if you look at my mail below I agree with you ie leave it because will you get a rod to do any better

Apologies to you OT I misquoted the point I wanted to and cocked up the reply and so have removed the offending (for want of a better word) bit

 

[LlandrilloSpark]

Based on my knowledge about the area, very sandy ground, historically the few tt's I've done have been in the 20-50 ohm range,that's why I thought RCD ing an existing reading of 2.08 would be acceptable

Lively debate though, better than x factor

 

[1shortcircuit]

Lively debate though, better than x factor

This is a great thread:thumbsup

I'm just pleased it's you in this position and not me