Earth rod

[Carlosfandango]

This might sound like a daft question to some of you guys. I've never had to work with TT systems before and I'm wondering how you go about getting a spike into rocky ground? The job I've been to look at has a spike in just now but the Ze at the mains is 107 ohms. I need to get this to an acceptable reading. I'm led to believe the area is build on bedrock! Any advice?

 

[trev]

As long as it's suitably sized and protected you're good to go mate

 

[shanky887614]

Just had a quick look on my digital version and cryptic as ever.

No mention of a distance but to be truthful I didn't look long

 

[Carlosfandango]

Cheers for the pointers. Time to get the books out I think!!

 

[Guest77]

This might sound like a daft question to some of you guys. I've never had to work with TT systems before and I'm wondering how you go about getting a spike into rocky ground? The job I've been to look at has a spike in just now but the Ze at the mains is 107 ohms. I need to get this to an acceptable reading. I'm led to believe the area is build on bedrock! Any advice?

Do you mean the Ra is 107 ohms? although I would consider that to be unstable, according to BS7671 it is perfectly within parameters and not considered a poor reading. Have you adequate protection in place? and have you considered another type of earth rather than a plain simple rod?

 

[Carlosfandango]

Do you mean the Ra is 107 ohms? although I would consider that to be unstable, according to BS7671 it is perfectly within parameters and not considered a poor reading. Have you adequate protection in place? and have you considered another type of earth rather than a plain simple rod?

Yeah 107 ohms Ra. The job is on a holiday site with individual chalets. The place is a shambles tbh. Owner wants eicr's done on the chalets. There's no rcd protection in place. My plan was to get a stable earth to carry out the individual reports then devise a plan for the supplies. Do you think this is the right route or am I on the wrong track??
This is the first time I've encountered TT.

 

[davesparks]

Could put a rod in at each chalet so that you create a fairly widespread web of connected rods.

 

[Guest77]

Yeah 107 ohms Ra. The job is on a holiday site with individual chalets. The place is a shambles tbh. Owner wants eicr's done on the chalets. There's no rcd protection in place. My plan was to get a stable earth to carry out the individual reports then devise a plan for the supplies. Do you think this is the right route or am I on the wrong track??
This is the first time I've encountered TT.

I would do the EICR and in the report I would follow the regs regarding TT systems and non compliance due to lack of RCD protection, section 7 has plenty of info, what I wouldn't do is touch the existing earth at all, that is something which you need to quote for should your report suggest it is not safe or stable, when you give a fixed price quotation for problems you have identified you could add that into the report, personally I think suggesting there is a problem with the earth when the reading is 107 ohms isn't the issue, lack of RCD and indeed possibly double pole protection (depending on the chalet) is the problem.

 

[Carlosfandango]

To be honest I think the sub mains need an overhaul! It used to be a caravan site but now has fixed chalets on the pitches. From what I've seen there are a couple swa's run out then multiple chalets have been tapped of it??!! I've yet to see one of these joints as the chalets are fully booked and the joints are under the floor's. Appears to be 16mm twins "tapped" of the armours. Would like to do the reports then try to get the remedial work! Something makes me want to walk away though!!:-S

 

[Guest77]

To be honest I think the sub mains need an overhaul! It used to be a caravan site but now has fixed chalets on the pitches. From what I've seen there are a couple swa's run out then multiple chalets have been tapped of it??!! I've yet to see one of these joints as the chalets are fully booked and the joints are under the floor's. Appears to be 16mm twins "tapped" of the armours. Would like to do the reports then try to get the remedial work! Something makes me want to walk away though!!:-S

I would be of the opposite mind, you could vastly improve the installation, I think you need to read section 7 first though for a bit of a brush up.

 

[telectrix]

as they're chalets, and presumably not metal skinned, consider the possibility of getting PME.

 

[Carlosfandango]

I would be of the opposite mind, you could vastly improve the installation, I think you need to read section 7 first though for a bit of a brush up.

I think you're right about brushing up ob section 7!
I heard from someone else that the owner is thinking about selling the site thus why he needs the report! I've not heard ut from the horses mouth though! I wouldn't imagine that he'll be keen on spending money on remedials!!!

 

[Guest77]

I think you're right about brushing up ob section 7!
I heard from someone else that the owner is thinking about selling the site thus why he needs the report! I've not heard ut from the horses mouth though! I wouldn't imagine that he'll be keen on spending money on remedials!!!

They never are keen to spend money, I would just do the report and stand your ground on your findings. The guy may sell the site in the future and the new owner may ask you to carry out remedial works based on your inspection.

 

[Carlosfandango]

Would you just test all 17 chalets with what's existing then? Obviously every circuit within each chalets is gonna fail on the earth loops!

 

[Guest77]

Would you just test all 17 chalets with what's existing then? Obviously every circuit within each chalets is gonna fail on the earth loops!

Yes I would test them as they are, the dead tests will tell you the state of the circuits and in theory if rcd protection was added the loop zs readings at around 107-110 ohms on the individual circuits would be irrelevent, I think 17 new dist board upgrades and some tidying up may be on the cards.

 

[Guest77]

Personally I think 107 ohms is unstable and I would attempt to improve that reading, but it complies to the regs lol