Earth Rod Issues

[Bennyboy70]

Hi.
Has anyone used Bentonite for a high resistance Earth rod? If so, does it work & where can i buy it as struggling to locate in builders merchants??

 

[Marvo]

Not sure about builders merchants but you should find it at any decent electrical wholesaler.

 

[GLENNSPARK]

Hi.
Has anyone used Bentonite for a high resistance Earth rod? If so, does it work & where can i buy it as struggling to locate in builders merchants??

so i suppose its a 3/8" twig you decided to use is it...

just get shut of it and go for 3 5/8" threaded rods with connectors....get it deep...

depth is key with TT...

 

[Bennyboy70]

so i suppose its a 3/8" twig you decided to use is it...

just get shut of it and go for 3 5/8" threaded rods with connectors....get it deep...

depth is key with TT...

The problem is sandstone about 2ft down!! I've had a steel rod and large sledgehammer trying to break through it but it's no good!! With the depth I can get I'm only down to about 430 Ohms.
so my only option as far as I can tell is digging down, breaking up sandstone with a breaker then using Bentonite or Marconite as a back-fill.
Anyone have any other ideas?!!!

 

[Sintra]

The problem is sandstone about 2ft down!! I've had a steel rod and large sledgehammer trying to break through it but it's no good!! With the depth I can get I'm only down to about 430 Ohms.
so my only option as far as I can tell is digging down, breaking up sandstone with a breaker then using Bentonite or Marconite as a back-fill.
Anyone have any other ideas?!!!

Personally I would drill through the sandstone with a long 14mm bit then drive in at least two 5/8 rods coupled together.

 

[Badged01]

depth is key

Thats what my missus keeps saying! But what I dont understand is that shes never put any earth rods in to my knowledge ......

 

[Bennyboy70]

That sounds like a cheaper & easier option!! Will give that a go first. Many thanks.

 

[Knobhead]

Personally I would drill through the sandstone with a long 14mm bit then drive in at least two 5/8 rods coupled together.

Best of luck, the Bunter sandstone beds where I live are well over 100’ thick. I’ve barely a foot of topsoil above the bedrock.

Nottingham’s Victoria Centre is on the same beds. The EMEB had to drill 150’ to get good readings for the two intake substations.

Bentonite you can get from a company called Vesuvius.

 

[Guest55]

Personally I would drill through the sandstone with a long 14mm bit then drive in at least two 5/8 rods coupled together.

thats sounds easy peasy just to say it , but actually doing it is a whole load of blood sweat & tears.
and your readings will still be crap for all that effort.

personally i'd just pay the dno for pme and sit on my arse drinking tea , smoking smokes etc , etc.
;-)

 

[Silly Sausage]

Best of luck, the Bunter sandstone beds where I live are well over 100’ thick. I’ve barely a foot of topsoil above the bedrock.

Look on the bright side, your house won't subside.
If you need an Earth, DIY PME!

 

[Knobhead]

It's already PME, all a rod would do is stop the house sliding down the hill.

 

[Engineer54]

Earth rods are not the only means of providing a TT system, but all of the alternative methods are going to be more expensive to install in both materials and labour costs!! Before you make any discussions on what you're going to do, try test drives in various locations within the properties boundaries to see if you can miss the sandstone.

Bentonite is fine for a lot of ground type conditions, but Marconite is by far superior and what's more, it's permanent!! It's also more expensive than Bentonite.... If you can't find a local supplier, you can always order either of these two rod/electrode enhancers from ''Furse''

If you run into trouble on this installation and need any further advice, you can always come back and ask!!

 

[Silly Sausage]

Have I to keep an eye on the Nottingham Gazette...
'Wizened Engineer found floating in The Trent after house collapse'

 

[spark 68]

I see Furse is now owned by ABB

Furse - Earthing, Lightning and Electronic Systems Protection

 

[GLENNSPARK]

Earth rods are not the only means of providing a TT system, but all of the alternative methods are going to be more expensive to install in both materials and labour costs!! Before you make any discussions on what you're going to do, try test drives in various locations within the properties boundaries to see if you can miss the sandstone.

Bentonite is fine for a lot of ground type conditions, but Marconite is by far superior and what's more, it's permanent!! It's also more expensive than Bentonite.... If you can't find a local supplier, you can always order either of these two rod/electrode enhancers from ''Furse''

If you run into trouble on this installation and need any further advice, you can always come back and ask!!

just wondering if tape or mat would be better here Eng?...try to get the increase in contact area this way....