After some advise please- Tn-s earth arrangement

[Jimmer84]

Evening all,

Just after some info on the photo attached. It’s a tn-s system with an Earth going to the cu met from under the floor boards. After lifting the boards I found the earth attached as so... I was expecting to see a clamp around the supply cable, not a choc block with legs of unknown origin attached. Can anyone enlighten me on what’s going on here? Thanks

 

[SparkyChick]

By way of an example... consider an SWA supply from the meter to a consumer unit some way away. There are various joins in that connection, this is acceptable. I find it hard to believe a correctly made join (say a crimp or a service terminal block) would not comply.

 

[Octopus]

Just because people can't be asked to study doesn't mean they can substitute opinion for fact.

I'm not stating an onion - its fact that "continuous" is not in the BYB or BBB

There is NO requirement that I am aware of for any spark to own and read all the Guidance Nuts .............

If this was so important, why isn't it stipulated in black and white in the BYB or BBB? Its not ..........................

 

[oracle]

Show us the regulation that stipulates earthing and bonding conductors have to be one continuous cable segment.

SC I did say clearly its Not in the Regs but stated in the GN8.

 

[SparkyChick]

SC I did say clearly its Not in the Regs but stated in the GN8.

I did scan GN8 but couldn't find anything that states this, can you point me in the right direction?

 

[Octopus]

SC I did say clearly its Not in the Regs but stated in the GN8.

So its not a reg then.

End of.

 

[Deleted member 9648]

The purpose of the 'continuous guidance' is to prevent loss of bonding downstream where a single conductor loops from one service to another should it be partially disconnected. There is guidance somewhere, I cant remember where, and that guidance also states that a durable maintenance free joint is acceptable, such as a non insulated crimp ferrule. But none of the above is a requirement of Bs7671

 

[oracle]

Show us the regulation that stipulates earthing and bonding conductors have to be one continuous cable segment.

SC I did say clearly its Not in the Regs but stated in the GN8.

By way of an example... consider an SWA supply from the meter to a consumer unit some way away. There are various joins in that connection, this is acceptable. I find it hard to believe a correctly made join (say a crimp or a service terminal block) would not comply.

A soldered connection or single MET are deemed acceptable

So its not a reg then.

End of.

We all know the Regs are not statutory, but they are the only code of practice we have. Guidance notes are supportive, like the Parts 1 to 7 of the Building Regulations

If you've got access to the NIC's technical manual, it's in part B37-21, section 7.

 

[Octopus]

We all know the Regs are not statutory, but they are the only code of practice we have. Guidance notes are supportive, like the Parts 1 to 7 of the Building Regulations

If you've got access to the NIC's technical manual, it's in part B37-21, section 7.

But you are stating them as if they are 100% regulations which they are not ........... so please stop.

Do a survey on how many sparks have the BBB or BYB plus all the guidance notes ................. I suspect it won't be many...........

As for the NIC manuals - no I don't and as they don't write the regs, its not relevant ......... they could be promoted as NICEIC "best practice" but the NICEIC still couldn't pick members up on assessments for things like this................... they can't be arsxd to follow up on poor practice of their members either ........... yet dare to use their logo and not be a member - you'll be up in court ..... misplaced priorities IMHO

 

[westward10]

You don't mind perusing the Best Practice Guides though do you?

 

[Upton Sparks]

What Conductor did you think you were following?

If that is the main earthing conductor, then you have a problem and would need to call out the national Grids local sub contractor to your area ( possibly UKPN)to look at fixing a new earthing point to the SWA of the Sub main cable. They will charge for this service.
If they cannot do this, you would need to look at changing the earthing system to a TT system or having the supply cable replaced with a TN-C-S

I would Inform the customer of the bad news, its not something which can be ignored even if you're getting a good Ze reading

 

[Jimmer84]

That looks suspiciously like a copper pipe... gas or water maybe, so my guess from afar would be that's bonding not the main earth.

Yea it’s the gas pipe, the meter is to the right of the photo

 

[Jimmer84]

That’s not pretty.

What’s the Ze like?

0.18

 

[Jimmer84]

What Conductor did you think you were following?

If that is the main earthing conductor, then you have a problem and would need to call out the national Grids local sub contractor to your area ( possibly UKPN)to look at fixing a new earthing point to the SWA of the Sub main cable. They will charge for this service.
If they cannot do this, you would need to look at changing the earthing system to a TT system or having the supply cable replaced with a TN-C-S

I would Inform the customer of the bad news, its not something which can be ignored even if you're getting a good Ze reading

It’s the ONLY “earth” cable going to the cu. There was no earth clamp at the top of the supply cable so I thought maybe for some reason the connection was under the floor board as that is where the “main earth” was coming from to then enter the cu. Upon lifting the board that is what I found! Pulled on the bare cables and they didn’t budge, all head off slightly different angles!!

 

[Jimmer84]

 

[Jimmer84]

Thought people might like to see the nest of tails accompanying the dodgy earthing system too