exported earth??????????????

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D Brennan

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Hi all got another question for you all, as you no im about to have my assesment by napit,, im thinking or rewiring my garage to be nspected on.

the garage is fed from main CU on a 20a breaker in 2.5 t+e then to a thru box were the armoured it terminated and goes underground to the garage.

Instaed of using the armoured cable as a earth they have run a 3core swa and used one of the cores as an earth. I have just been reading some threads on exported earths, my earthing system is pme, the cable supplying the garage is rcd protected from the cu in the house but just a normal 3 way cu in the garage.

If i rewire the garage for my installation to be tested on is the exported earth going to crop up??? is it an exported earth, im thinking so from what ive read.

i would say the swa run to the garage is about 15m in lenth.

all help appreciated cheers

 

M107

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Nothing wrong with exporting the pme (not my prefferred method but each to his own) so long as there are no extraneous-conductive-parts (water / gas etc) in the garage.

 

D Brennan

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Steptoe. He has written pages of pontification on the dangers of exporting the earth. Have you seen the 2 long threads?
ye thats what got me worried although i have fed garages like that many times. :eek:

 
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For my sins, I do not export a pme earth. I make the outbuilding TT. But thats just my opinion.

I am not getting into the arguments for and against again. It has been discussed many times, as apache has so obligingly linked to above (thank you mr. vet!)

KME

 
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Hi KME,

Before driving the earth rod into the ground, what checks do you make to ensure their are no hidden services below ground?

I was at my Aunts house last week and the electricians a few doors away had ran swa to garage behind the property, but damaged an underground water pipe as well so Severn Trent had to come out.

Just seems a bit risky to me, especially as I was told when doing 2330 that earth rod was to go in soil that had not been dug up etc.

 
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Hi KME,Before driving the earth rod into the ground, what checks do you make to ensure their are no hidden services below ground?

I was at my Aunts house last week and the electricians a few doors away had ran swa to garage behind the property, but damaged an underground water pipe as well so Severn Trent had to come out.

Just seems a bit risky to me, especially as I was told when doing 2330 that earth rod was to go in soil that had not been dug up etc.
Good point. Did you see Bobski the builder on tv last week where they found a 11kv cable running through a back garden

 
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There are 3 choices here (I think):

1... use a digicat to find underground services.

2... use the plans, and locations of manholes, etc. to locate a (hopefully) safe spot.

3... Offer up a prayer to the high god of sparkies, and hit the damn rod in, nice and hard. Law of avarages says you`ll miss most of the time.

In order of preference, time & cost. In reverse order of popularity and usage! :)

 
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Was thinking digicat but never used one, dont really want the outlay on something thats not going to be used that often as well. When it comes to it I think it will be a combination of options 2 & 3, maybe some prayers and getting down on me hands and knees to kiss the ground Pope stylee, before driving that metal spike into the unknown!

Yes i did see Bobski the Builder, FYI you can view the programme on channel 4 website within 30 days of it being aired on TV. Disgraceful towards the end of the programme how that customer was talking to the Polish builder, I wouldnt have stood for that but then again you dont know how much was "just for show" to make the programme better.

 

Mr Sworld

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Was thinking digicat but never used one, dont really want the outlay on something thats not going to be used that often as well.
You can always hire one out for the job and add it to the bill....

 

steptoe

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Hi all got another question for you all, as you no im about to have my assesment by napit,, im thinking or rewiring my garage to be nspected on.the garage is fed from main CU on a 20a breaker in 2.5 t+e then to a thru box were the armoured it terminated and goes underground to the garage.

Instaed of using the armoured cable as a earth they have run a 3core swa and used one of the cores as an earth. I have just been reading some threads on exported earths, my earthing system is pme, the cable supplying the garage is rcd protected from the cu in the house but just a normal 3 way cu in the garage.

If i rewire the garage for my installation to be tested on is the exported earth going to crop up??? is it an exported earth, im thinking so from what ive read.

i would say the swa run to the garage is about 15m in lenth.

all help appreciated cheers
sorry for the delay, been away

but as Mr Apache so rightly points out,

I would deffo NOT export the PME,

as the reasons I think have clearly been stated many times in the links.

back to your situation tho,

are you saying this cable has NO mechanical protection outside?or has the armour also been used as an earth?

15m away, extraneous parts or not I would argue that its is simply TOO far from the equipotential zone to be permitted to be classed as the same installation and not as a submain, domestic purposes only,

IMHO commercial/industrial would be treated in a totally different manner, due to the more rigorous circumstances involved.

 
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