Transporting TT earthing?

[mjf]

I know the subject of transporting pme from a house to an out building has been discussed many times.
This question is the DNO is only providing a single phase no earth TT supply which is fine. Want to run a sub main with swa to an out building approx 30m away. Would you only connect the the armour supply side (at the house) and only use a plastic gland outbuilding side or would you use an swa gland both ends and fit earth rods at both buildings all linked together or rods at both buildings but the earths are not connected between the two. This is small holding no other properties nearby.

 

[Wilko]

would you use an swa gland both ends and fit earth rods at both buildings all linked together

Hi - this is what I normally do. It gives a lower overall result and improved resilience (in case one rod / connection is lost somehow).

 

[telectrix]

as above. rod and earth both ends, better still is add a rod or 3 more, 1 at each end > 1m from existing .

 

[Mike Johnson]

Any additional rods should be outside the zone of influence of the closest rod, this means at least the length of the existing rod away from any other.

 

[nicebutdim]

Any additional rods should be outside the zone of influence of the closest rod, this means at least the length of the existing rod away from any other.

Is this correct or should they be spaced by the the combined length of both rods?

 

[Mike Johnson]

You could be right, I will have to look it up again, for some reason 2.2 times rings a bell.

 

[Strima]

Any additional rods should be outside the zone of influence of the closest rod, this means at least the length of the existing rod away from any other.

Three times the length of the original rod to ensure you're outside the sphere of influence. There is a calculation for this but this is a good rule of thumb.

 

[Mike Johnson]

OK we have "One", "Two", "Two point two" and "Three" and advance on these going, going G...........?

Earthing Practice - Copper Development Association​

https://copperalliance.org.uk › resources › pub-11...

 

[Soi disant]

30m of copper tape laid in the trench, connected at each end.

 

[telectrix]

30m of copper tape laid in the trench, connected at each end.

church roof with tin snips tonight then?

 

[Soi disant]

OK we have "One", "Two", "Two point two" and "Three" and advance on these going, going G...........?

Earthing Practice - Copper Development Association​

https://copperalliance.org.uk › resources › pub-11...

Surprising that David Cockburn isn't one of the contributors.

 

[Soi disant]

Earthing Practice - Copper Development Association
https://copperalliance.org.uk › resources › pub-11...

"Bentonite .. is a natural forming, pale olive brown clay which is slightly acidic, having a pH of 10.5."

Hmmm.

 

[Mike Johnson]

Geophagy has been considered as an adaptive behavior in humans and animals (1) and the clays have been considered the healing materials from ancient times. As geophagia is an occasionally habits of animals and humans (babies and pregnant women), physiologically it is assumed that earth might have some beneficial effects on body function. Bentonite is absorbent aluminium phyllosilicate clay. It is named after Fort Benton, Wyoming where its largest sources are found.

 

[nicebutdim]

All well and good, but I believe the point was that Bentonite can not be 'slightly acidic' with a pH of 10.5.

 

[Mike Johnson]

All true, I missed that point, obviously thought the post was referring to Bentonite not being a natural clay.