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Discuss What is my Earthing Arrangement? in the Electrical Forum area at ElectriciansForums.net

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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.
 

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buzzlightyear

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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

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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
 
It is a concern you are replacing a consumer unit and using pictures from the OSG to try and determine the earthing system.
 
  • Thread Starter Thread Starter
  • #8
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.
Post automatically merged:

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
 
Last edited:

telectrix

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

Andy78

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Test pefc and pssc and compare results ?

Your profile lists you as a diyer which is very concerning.
 
  • Thread Starter Thread Starter
  • #13
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

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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.
 

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