General Q about earth rods

[ban-all-sheds]

As part of some work being done next year I'm going to be installing an infrastructure ready to make use of an emergency generator.

I'll have the opportunity to put a length of copper "tape" (10-12m) in a trench, instead of a conventional rod. Is this likely to be a better alternative?

Soil is clay, and whether I use a rod or a tape in the trench it will all be concreted over.

If I do use tape, how/where is it terminated to the cable running to the house? Bent through 90° underground, and taken into a pit just like the top of a rod would be?

 

[djrichie_t]

Along the length of the tape, I would attach a couple of rods, then use the rod to attach the tape and cable to.

Dont forget, taking a leak on the tape in the trench will do wonders to get them readings down (old electricity board trick) and the chemicals will stay in the soil

After a heavy night out gives the best results

 

[Taylortwocities]

So (to paraphrase BAS)

"If I had known that I was going to be measuring my earth electrode resistance this morning I'd have drunk more beer last night."

 

[ban-all-sheds]

Along the length of the tape, I would attach a couple of rods, then use the rod to attach the tape and cable to.

Why a couple?

Dont forget, taking a leak on the tape in the trench will do wonders to get them readings down

That's one hell of a leak - the trench will be nearly 15m long....

(old electricity board trick)

Must be interesting to watch, in these days of equal opportunities...

and the chemicals will stay in the soil

After a heavy night out gives the best results

After a heavy night out it's almost pure water....

And would I want to be blundering about in the dark, drunk, near an open trench?

 

[securespark]

Nice to hear from you again, BAS!

 

[efiste2]

Got to agree with DjRichie, Earth rods and Copper tape will give the best results, especially when "leaked on" , Tape alone in a trench will sit in broken ground and give poor readings, whereas an earth rod/s will be driven in at a good depth, into unbroken ground and give better readings. Always harder work installing private/consumer or O/H network earth mats as they are independent from the local ROC underground network, we usually used stackable rods, to get a greater depth. and better readings, connected to a common copper tape and then nursed our bad backs as we tested the resistance, then either prayed for rain or as Djritchie says, took a leak on the rods!!!!

 

[ban-all-sheds]

Well if tape is going to be flaky, I can't see what benefits it would add to a properly driven rod.

Particularly as the stuff is far from cheap.

I'll just go for a normal rod.

 

[ricicle]

Wetting the ground around an earth rod/tape is NOT the correct method of ensuring the resistance meets recommended levels!

 

[ebee]

I can`t claim any experience with tape, not many TTs either for that matter.
A couple of rods and test them is what I`d be considering.
I`d preffer to test under worst possible conditions - frozen soil or after a several days heat wave. Ok that might not be possible.
How much is the tape Ban and what are it`s dimensions?

 

[Lectrician]

In the past we have fitted hard drawn uninsulated copper cable in the trench - 70mm. Once back filled we did a test to it prior to terminating and the results where very impressive.

If driving rods in aswell, drive them in at a slight angle. Thats a tip I have always been told.

 

[ban-all-sheds]

How much is the tape Ban and what are it`s dimensions?

Well I've not done much of a search, so maybe the first supplier I looked at after googling is outrageously expensive, but they want £6.42/m inc for 25 x 3mm tape...

But I doubt if it's wildly uncompetitive - that tape is 75mm², and when you think about the cost of cable....

 

[toasty]

what about an earth grid?

When I did my garage, I used both an earth rod and also connected the rod to the reinforcing steel grid work I had used for the concrete base, I don't have a earth impedance meter, but doing my favourite ligthbulb between earth and live and measuring the voltage and current indicated a nice low Z

You'll probably all tell me that you can't do this for some reason of regulations, but steel reinforcing mesh for contrete floors is fairly cheap to buy - and might be a suitable alternative to tapes and/or rods.

Oh and welcome back BAS!

 

[ban-all-sheds]

Steel reinforcing mesh just buried in the ground is likely to rot, no?

 

[toasty]

Yeah!

Fair point actually..

Dunno if you can either:
a) get galvanised stuff
b) completely remove any trace of water from your garden

 

[ban-all-sheds]

Yeah!

Fair point actually..

Dunno if you can either:
a) get galvanised stuff

I'm starting to like the earth rod idea more and more...

b) completely remove any trace of water from your garden

That would give me a nice low Ze, wouldn't it....