What is my Earthing Arrangement?

[Deleted member 123470]

Hi,

I'm currently installing a new consumer unit and I cannot clearly identify my earthing arrangement.

(image attached)

I am leaning towards TN-S but could potentially be TN-C-S as it is a unit installed in the 70's and doesn't match the drawings in the OSG. Any expert advice would greatly appreciated.

 

[buzzlightyear]

If the earth is combined with head then a tncs or the earth combined in swa then a tns if no earth present then TT .can you see a swa cable .if not then a tncs .

 

[Des 56]

The earthing type or lack of information can only be provided by the supplier

You need to assume that you have to provide your own means of earthing unless or until the supplier says otherwise,best go on the phone and start asking

 

[fairlight]

Is that black lead apparently coming from the lower left of the head an earthing conductor?

 

[westward10]

It is a concern you are replacing a consumer unit and using pictures from the OSG to try and determine the earthing system.

 

[Baddegg]

Got any better pictures?....@stavros79

 

[Dustydazzler]

Don’t think it’s a tns

Have you done a Ze at the old fusebox by any chance ?

 

[Deleted member 123470]

Is that black lead apparently coming from the lower left of the head an earthing conductor?

Yes it is, it feeds directly into a MET then to the current consumer unit.
[automerge]1572685823[/automerge]

Don’t think it’s a tns

Have you done a Ze at the old fusebox by any chance ?

Not yet, will be the first thing I do before replacing the CU to make sure it's within 0.35 ohms. Just trying to determine the arrangement before doing the paperwork so I can challenge the supplier if their is a problem. Its a very old system an falling to bits

 

[Dustydazzler]

Yes it is, it feeds directly into a MET then to the current consumer unit.

Bootleg pme then ?

 

[telectrix]

my bet is that it's sweated onto the incoming cable sheath, under that plastic below the fuse.. therefore TN-S.

 

[Deleted member 123470]

my bet is that it's sweated onto the incoming cable sheath, under that plastic below the fuse.. therefore TN-S.

That's what I was thinking, cheers. I think I'm going to ring the supplier just to be certain.

Tganks

 

[Andy78]

Test pefc and pssc and compare results ?

Your profile lists you as a diyer which is very concerning.

 

[Deleted member 123470]

Test pefc and pssc and compare results ?

Your profile lists you as a diyer which is very concerning.

I'm Part P qualified and have a lot of experience with basic electrical work. so have the necessary knowledge to make these upgrades. DIYer was the best fit option. Just got caught off guard by this old cut out. Appreciate the concern buddy

 

[telectrix]

I'm Part P qualified and have a lot of experience with basic electrical work. so have the necessary knowledge to make these upgrades. DIYer was the best fit option. Just got caught off guard by this old cut out. Appreciate the concern buddy

maybe you should edit your profile. if you've done a short course and joined a scheme, then Domestic Installer would be appropriate. If you don't have that option, I'm sure Dan could make it happen.

 

[Baddegg]

Part p is not a qualification mate....