Advice please re: Duty of Supplier

[plugit]

Hi
Please could I seek advice on the following points:

1. My consumer unit is supplied directly from the base of the meter, ie not through an isolating switch. If I request an isolating switch will I be responsible for any costs? Will the supplier do this at my request, ie customer rather than a qualified electrician?

2. I have a new (unused) MK box (isolator with only room for one double switch) fitted with a 100A Main Switch (5500s) is this the type of isolator I should have and would the supplier connect to this? Is this sensible or should they supply and fit?

3. The earth from my consumer unit wraps around the soldering of the suppliers cable (ie. the bulbous part of the supply) but appears not to be bonded. Apart from wanting to fix this asap for my own safety, whose responsibility is it and would an earth rod help / be preferable?

I am in Epsom Downs, Surrey and supplied by EDF. I mention this to clarify I am not in a rural location

Thank you for any advice, apologies for lots of questions!

View media item 37560

 

[Taylortwocities]

They may charge you for an isolating switch. But why do you want one? There is one on your consumer unit, isn't there?

The MK box would not be suitable. If the DNO wants to supply a switch they will provide one of their own. It may look like one of THESE .

Note that it has moulded supports for the meter tails.

NO you must not put in an earth rod. Your supply appears to be TN-S and the installation will be engineered for that supply type. If you change the main earth to an earth electrode then a whole heap of things have to be changed and then tested.

Need a picture of your earthing issue. Lets see the connections. That may be a reason to get the DNO in, but lets see first.

 

[JohnW2]

It may look like one of THESE .

I note with interest that this item offered for sale on eBay has a sticker saying "Property of Norweb plc" on it

Kind Regards, John.

 

[plugit]

Taylortwocities

Thank you for your advice.

I thought it would help a subsequent re-wire and enable a contractor to connect up without breaking the supplier seal - or are they allowed to do that?

I will not use the MK box - thanks.

Will post an image of the earth connection, but unable to do so tonight.

I appreciate your trouble in replying, thanks again.

 

[RF Lighting]

Leave it up to your electrician to decide if they want / need a switch. Personally I wouldn't thank you for having one installed.

 

[plugit]

RF Lighting

With over 13,000 posts this is your territory not mine, but I am intrigued by:

"Personally I wouldn't thank you for having one installed" (isolator)

IEE Guide to Building Regs shows an isolator in all three system types, but you don't want one? Please don't misunderstand me, I am not trying to be smart, merely to understand, so are they undesirable / unnecessary? (as alluded to by Taylortwocities).

Thank you for trying to educate a numpty!

 

[Roo]

1. My consumer unit is supplied directly from the base of the meter, ie not through an isolating switch. If I request an isolating switch will I be responsible for any costs? Will the supplier do this at my request, ie customer rather than a qualified electrician?

IMO yes get one installed.
Some suppliers charge, some suppliers don't and some suppliers only charge when their customers are in certain areas.
If they do try and charge then kick up a fuss and threaten to change suppliers etc.

2. I have a new (unused) MK box (isolator with only room for one double switch) fitted with a 100A Main Switch (5500s) is this the type of isolator I should have and would the supplier connect to this? Is this sensible or should they supply and fit?

The supplier I work for only let us connect up to their supplied isolators.
If anything were to go wrong with an isolator supplied by the customer we would not be allowed to change it for one of ours, as this would be deemed working on the customers equipment which we are not allowed to do.
I would probably end up being told to fit an isolator so a spark could change the damaged isolator??????

3. The earth from my consumer unit wraps around the soldering of the suppliers cable (ie. the bulbous part of the supply) but appears not to be bonded. Apart from wanting to fix this asap for my own safety, whose responsibility is it and would an earth rod help / be preferable?

It's my understanding that where an earth is provided by the DNO (like the type you described) it is their responsibility to maintain it (ie if it becomes loose not within limits etc etc) but only up to the point the earth is supplied usually an earth block close to the cutout.
Where no earthing connection is left an electrician needs to provide their own earth (Earth spike on SNE overhead supply for example) which is then nothing to do with your DNO.

If your worried about your earthing arrangement get a spark in to check.

 

[ban-all-sheds]

The earth from my consumer unit wraps around the soldering of the suppliers cable (ie. the bulbous part of the supply) but appears not to be bonded.

I'm confused - what isn't bonded?

 

[ban-all-sheds]

The MK box would not be suitable.

Why not?

Note that it has moulded supports for the meter tails.

Ah - you mean moulded supports that not one single henley block or CU in the land has for the tails that go into them?

 

[ericmark]

NO you must not put in an earth rod. Your supply appears to be TN-S and the installation will be engineered for that supply type. If you change the main earth to an earth electrode then a whole heap of things have to be changed and then tested.

When is an earth rod (earth electrode) not an earth rod?
Answer when it's an extraneous-conductive-part or an exposed-conductive-part.

I think this is confusing to an ordinary person! You are correct in he must not transfer the earthing arrangement from a TN to a TT system. And yes you are correct he therefore can't fit an earth rod. But that does not mean he can't put a copper coated steel rod in the ground and connect it to the earth. What it means it's not called an earth rod.

The only thing one can't do is use the name "Earth Electrode" you can still install it and connect it but it's not called an earth electrode its called an extraneous-conductive-part.

I had a huge argument about this where an electrician phoned the DNO and asked what the supply type was and was told it was TN-C-S he then informed the DNO that their supply was faulty in that there was no earth connection supplied and installed a earth cable for them to connect when they arrived. He did not isolate supply and did not fit an RCD or an earth rod as he said your not allowed an earth rod with a TN-C-S supply.

Two months latter the DNO had still not connected the earth cable and I fitted a temporary earth rod and RCD until next day when they converted back to TN-C-S. I did not need to remove either rod or RCD although (before 2008) I did remove RCD as it was part of my emergency stock.

Yes the DNO made a mistake but so did the electrician and it is this pedantic comments that you can't fit an earth rod to a TN system which caused his error. I know it's not called an earth rod once the TN system is installed but it is still the same copper coated steel rod with same wires connecting it only the name has changed.

 

[plugit]

I think this is confusing to an ordinary person!

ericmark
I'm glad you said that - there is clearly some disagreement about several of the points I raised amongst the learned community!

Thank you to all who contributed - I think I have the points covered:

1. The DNO may or may not fit an isolator and may or may not charge me.

2. I could have my own isolator installed but this may / may not be a good thing / necessary / desirable.

3. I should not fit an earth rod - or an extraneous-conductive part with my existing system. Obviously, I need the existing earth to be properly bonded. On this point it seems there is agreement.

I didn't inform you that I had requested the DNO to upgrade the tails in anticipation of upgrading my side of the supply. The image shows the response left by the 'professional' employed by EDF. I presume (hope) that a scribbled note on a small jotter is not industry practice?

View media item 37570
My posting is intended to help me learn / inform / encourage debate, not to insult anyone or their profession.

 

[bernardgreen]

I know it's not called an earth rod once the TN system is installed but it is still the same copper coated steel rod with same wires connecting it only the name has changed.

Pedantic Rules over common sense

I wonder if a hollow copper coated steel tube driven would be classed as pipe and treated differently to a solid steel rod coated in copper and driven into the ground.

I ask because there is a house with TT and two metallic water pipes coming from the ground into the house where pedantic rules apply.

There is a bond wire to the extraneous pipes and running parallel with it along the wall a separate earth conductor to the ground rod. The ground rod is about a foot away from where the water pipes come out of the ground. The bond wire and earth wire are of course both green yellow but clearly different diameters and both go to the same earth bar inside the consumer unit

 

[ban-all-sheds]

You are correct in he must not transfer the earthing arrangement from a TN to a TT system.

Actually I think you'll find that he is quite at liberty to eschew the DNO provided earth and have a TT supply if he wants to.

And yes you are correct he therefore can't fit an earth rod. But that does not mean he can't put a copper coated steel rod in the ground and connect it to the earth. What it means it's not called an earth rod.

If he had a standby generator installed, with a changeover switch, and the generator neutral connected to a copper coated steel rod in the ground, what would the rod be?

 

[ban-all-sheds]

3. I should not fit an earth rod - or an extraneous-conductive part with my existing system.

There is probably no need to install an earth rod, and if there isn't then installing one would be pointless.

The only way to know is to have your electrician measure your Ze, and if that's too high find out if the supplier will change you to a TN-C-S supply or if you'll have to go TT.

Obviously, I need the existing earth to be properly bonded. On this point it seems there is agreement.

I think I've realised what you mean by this - you mean the connection to the sheath needs to be properly made.

That's not what "bonding" means.

View media item 37570

I love #6.

This is what's under my stairs:

And it's been like that for 50-odd years, thanks to the the suppliers.

Since neither of them will move anything to resolve issues of their making at their expense it can b****y well stay that way.

 

[JohnW2]

You are correct in he must not transfer the earthing arrangement from a TN to a TT system.

Actually I think you'll find that he is quite at liberty to eschew the DNO provided earth and have a TT supply if he wants to.

I'm sure that's true. In fact, ericmark was somewhat misquoting (well, only partially quoting) TTC, who actually went on to say that if one did change a TN to a TT system, then 'a whole heap of things {would} need to be changed and tested' - which obviously is potentially true, particularly in relation to fault protection.

However, I think it goes further than you suggest, in that I don't thing one even has to 'eschew' the DNO-provided earth in order to connect an (additional) earth rod, should one so wish. Let's face it (somewhat echoing Eric's and Bernard's comments), if any metal pipe/rod/object in the ground enters the building, then one is required to connect it to the MET, and I can't see why calling it an 'earth electrode' could suddenly make that 'forbidden'!

Kind Regards, John.