Earthing a storage container

Came into work today to find a job request for lighting in a shipping container! 

Ok so it's been a while since I have dealt with this sort of thing and there appears to be a a few gaps in my knowledge!

...

I get to the depot, and the manager (Gary) suggests I Chuck an extension lead out the window, Sorry Gary its not that simple. 

So... how hard can it be?   :lol:

It's a metal container on concrete probably about 15m from the main TP DB, there is a 4mm SWA on a 32a type C feeding an 11a forklift charger.

I was hoping to further extend this circuit To incorporate a 13a fused supply to the container to provide lighting and one socket.

But the age old question of earthing an out building on a PME supply has reared its ugly head again...

My thoughts would be to put in an earth rod but access to the earth is limited by thick concrete.

I make the assumption that bonding back to the PME is not an option even if the bond is 1/2 the size of the incoming neutral?

Also there is RCD types to concider...

I have had a look on the internetz  and all I get is arguments, also only have my unite guides with me as all my books are in the shed!  :facepalm:

Just earth it off the cable and be done with it, you'll never get a better earth with a rod than off the mains, personally I think too many people like creating problems.

Earth it off the cable,

But, personally, I think it needs rodded as well to bring it to the same potential as the general mass of earth

I would class a metal shipping container the same as a caravan and NOT export a PME earth to it, but TT it.

Isn't the issue, PME, outer CNE fails, whole install rises to near L potential, guy standing on the ground about to enter the container (caravan) grabs hold of the metal door handle on the metal door bonded to earth (now at near L potential)......... baddayexplode

If you don't agree with that, explain why you never export PME to a caravan but it's okay on a metal container.

I agree with prodave. From memory the regs do not refer to "caravans" but to "caravans and similar structures"

john..

i would TT it

agree with the above. If you did export the PME to the container, I would at least want earthed armour, CPC and 30mA RCDs on all circuits, and class II everything.

I'd BURY it!  :coat

that's a big hole, but at least the container would be in direct contact with earth :^O

binky said:

that's a big hole, but at least the container would be in direct contact with earth :^O

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Exactly my thinking!  You'd need to take the paint off ideally!

binky said:

that's a big hole, but at least the container would be in direct contact with earth :^O

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A guy in Nottingham managed to bury a container for his horticultural hobby.

Thanks for your input gentlemen! As always appreciated!

I like the way the first 3 answers to the question are different! :lol:

Just goes to show how ambiguous these things are...

Something I found annoying is that there is tons of info on locations containing a bath or shower but fudge all on metal containers, although I will give special locations a good read tonight!

If you had a storage container and buried it in the ground to grow "tomatoes" then how would you earth it? Is a caravan or a horticultural installation? Could even be a fair ground with all them tinkers about... h34r:

I declined the job btw, I don't have all the equipment needed to install a rod (don't do many rods down ere) and with concrete everywhere it was starting to look like a bit of a mare. They'll probably send me back! :lol:

Is the main building steel framed or steel clad?

If so how far from the building is the steel container <2m, TN-C-S, > 2m probably "True PME", or TT as a second choice.

Steel framed, container is less than 2m away, annoyingly close to the building.

It's a TNCS with PME don't mess with this stickers on the service head.

Blue Duck said:

Steel framed, container is less than 2m away, annoyingly close to the building.

It's a TNCS with PME don't mess with this stickers on the service head.

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TNCS then, with a bond back to portal frame of main building, same size as N unless you want to calc it. 

steptoe said:

TNCS then, with a bond back to portal frame of main building, same size as N unless you want to calc it. 

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Wot e sed! ^

Sidewinder said:

Wot e sed! ^

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Exactly, 

That's why I scoobed you,

Cheers guys!!!

It's been a good exercise in getting the grey matter going again after many weeks of being stagnant.

But like I said I have limited kit at the moment and can't afford to splash out on 35mm crimpers ans whatever else I need for these Sprouts.

lump hammers crimp well :innocent

wot e sed ^