hotel Ze 2.8 ohms

[topquark]

I tested a TN-S system today and got a value of 5.85 ohms - the reason, no bonding connection between the CU and the main connection point provided by the DNO.

Seems it may have been like this since 1966 when the house was built!

I take it you mean for a Zs reading not Ze?

 

[Octopus]

I take it you mean for a Zs reading not Ze?

Yes ZS, should have made that clear on my post. ZE "impossible" with a cable to connect to!

 

[Deleted member 9648]

rcbo th circuits

Isnt that treating the symptoms rather than the cause?

 

[TPES]

Today I tested a Ze on TN-S to be 1.62

Obviously this would throw all my Zs values out. So rang central networks and they said someone will be out straight away, 1 hour later they turn up, confirm with there own meter I am correct in my Ze reading. He pulls the main fuse and that's it... It's not going back on.. The home owner was gob smacked! Powers off me duck and not going back on until they've dug the road up and sorted the problem.

He then goes to the house next door and gets an external loop of 2.41.... Fuse gets pulled and the family with all the children are very upset at having there power turned off all of a sudden!

I had also pee'd off the kitchen fitters and plumbers working in the house...if I had not turned up to test this power cut would of never happened!

 

[topquark]

Today I tested a Ze on TN-S to be 1.62

Obviously this would throw all my Zs values out. So rang central networks and they said someone will be out straight away, 1 hour later they turn up, confirm with there own meter I am correct in my Ze reading. He pulls the main fuse and that's it... It's not going back on.. The home owner was gob smacked! Powers off me duck and not going back on until they've dug the road up and sorted the problem.

He then goes to the house next door and gets an external loop of 2.41.... Fuse gets pulled and the family with all the children are very upset at having there power turned off all of a sudden!

I had also pee'd off the kitchen fitters and plumbers working in the house...if I had not turned up to test this power cut would of never happened!

Ask them if they'd rather fry in the event of a fault!

 

[TPES]

rcbo th circuits

Surely this is not an option..

30mA giving 1667 ohms max on Zs, but with this high Ze would there still be a safety issue?

 

[topquark]

Surely this is not an option? Is it?

30mA giving 1667 ohms max on Zs, but with this high Ze would there still be a safety issue?

No, it's not!!!

 

[Deleted member 9648]

Surely this is not an option..

30mA giving 1667 ohms max on Zs, but with this high Ze would there still be a safety issue?

It would work and provide fault protection that meets the requirements.....but clearly something is not right....dont just treat the symptoms,rectify the cause.

 

[TPES]

It would work and provide fault protection that meets the requirements.....but clearly something is not right....dont just treat the symptoms,rectify the cause.

Agreed!

I suppose I could of carried on testing today then instead of saying I'll be back Monday. Just noting on the cert of a high Ze and DNO to rectify.

 

[Des 56]

Today I tested a Ze on TN-S to be 1.62

. He pulls the main fuse and that's it... It's not going back on.. The home owner was gob smacked! Powers off me duck and not going back on until they've dug the road up and sorted the problem.

He then goes to the house next door and gets an external loop of 2.41.... Fuse gets pulled and the family with all the children are very upset at having there power turned off all of a sudden!

!

I always was under the impression that in cases like this,they fit an whole installation 30 m/amp rcd as a temporary measure,not just pull the power on people
There is also the question of, when there are children involved,they are not supposed to just cut and run
Perhaps the Tns earth connection could have been considered as a sufficient temporary electrode for a temporary TT system

 

[TPES]

The engineer that came out from DNO had the whole region electricity supply all mapped out on his laptop, shown exactly what phase and how many coming down the streets and where joints were made in the pavement to each property.

This was just a file stored on the hard drive of the laptop he said...

Anyone know where this file can be located from legitimately? It just looked very interesting and wouldn't mind a copy

 

[nickblake]

As you know maxZe for a TNS supply is 0.8 ohms with readings like that i would contact the DNO get them to check it , they will soon tel you if its a differant , this type of high reading could be the start of a major fault ,

just spotted your post what did he say

 

[tester11]

had a further look yesterday at the earthing, tried continuity test between clamp and sheth just below cut out and was gettin no reading turns out that the original clamp had actually been clamped round a very thin layer of the incoming cable material and was gettin very poor connection. put new clamp on below cut out and new Ze reading of 0.18. happy days !!! wonder why no one has dealt with this issue previouslyas there are testing labels on various boards round the hotel where the sparks must of been gettin a high zs and havent done anything about it !!! WTF

 

[topquark]

Coz they haven't been professional enough to fix the problem, full marks that man!

 

[Deleted member 9648]

OOer.....hope you didnt put a standard bonding clamp on it !