Ze on Tn-s

[jenions]

first time ive came across this so just wondering what i should do? measured a ze of 0.8 on a tn-s so its border line max value is it safe to leave or will it cause issues if left? apologies if its a stupid question, its the silly things that catch you out

 

[Deleted member 26818]

I believe that 0.8Ω is the maximum allowed in the guidelines.

 

[telectrix]

a call to DNO expressing concern that it could go above 0.8 might be a good idea. (CYA)

 

[spamwize2]

i would dno it

 

[MarkieSparkie]

Report it to the DNO, you will have discharged your duty of care on behalf of your customer and that way it won't rebound at a later date. Remember to record your actions as an appendix to your certificate/report.

 

[jenions]

trouble is customers a bight tight so if the dno charge he wont have it done

 

[telectrix]

the DNO have a duty to maintain any earthing arrangement they supply, so they should not charge. as long as you have informed them (in writing is best) then you've covered your arse. as markie says. note it on the report.

 

[ezzzekiel]

As its within dno guidlines i doubt they would be too concerned so i wouldnt worry youve recorded on your cert but if the higher ze is causing too high zs values then chase it up

 

[chiplard]

Just a thought but what Instrument are you using? Is it a Fluke

I had my assessment last week and my assessor mentioned something that I didn't realise I had to do. If you have a Fluke then the ELI test facility on the meter needs nulling, if not done it can give false high readings.

 

[oldtimer]

Also have you measured it on the main earth alone ? and not with all the earths commoned I measured 0.9 on a job and told the owner after the DNO sorted it out to inform the guy downstairs because he could have been in the same situation as him but now he has his earth sorted out and his water and gas pipes (that run through the guy downstairs) earthed he now has a good earth through his bonding to the gas and water

 

[SW1970]

Just a thought but what Instrument are you using? Is it a Fluke

I had my assessment last week and my assessor mentioned something that I didn't realise I had to do. If you have a Fluke then the ELI test facility on the meter needs nulling, if not done it can give false high readings.

It mentions this in quick start guide, the zero adaptor guide and the full instruction manual. If you've zero'd it against a wander lead at some point, it might also be giving false lows which could mean a re-check of some results might be required.

 

[jenions]

got megger 1552 so no worries about the fluke and i got 0.8 with just main earth, nothing connected. if DNO will do it foc then thats ok, its going to be my assesment job and they come on 12th oct so gonna ring nic assessor check his opinion