Extraneous Parts Earth sizing

[Neon Vagabond]

Customer wants to take power from an existing garage (with board) to supply a greenhouse, to be fitted with ip rated switchgear.
The greenhouse is made of aluminium.

Since this is an extraneous conductive part am i right in thinking that the aluminium frame would require a 10mm bond at least? (tncs supply)

Garage is fed with a 4mm armour (3core)

Should i still take the supply from the garage but run in a seperate 10mm earth from the house MET?

 

[Strima]

Why not TT it?

 

[Neon Vagabond]

i dont know, ive always had a bad feeling about TT

 

[Neon Vagabond]

Im also not really sure whats down there

 

[Dave OCD]

It isn't necessarily extraneous if mounted on a concrete plinth, I'd test it.

 

[Wilko]

What's being put in the greenhouse? Maybe an IP rated outlet just outside it would allow use of garden tools etc.

 

[Neon Vagabond]

the guys wanting a light, lightswitch and 2 sockets. He says he plans on putting a 1kw heater in there as well (plugged in)

 

[Neon Vagabond]

It isn't necessarily extraneous if mounted on a concrete plinth, I'd test it.

not heard about this...

 

[Dave OCD]

I'm surprised you're not aware, but if the metalwork tests at >22kOhms to earth then it isn't extraneous.

 

[buzzlightyear]

not heard about this...

Concrete slab - Wikipedia - https://en.wikipedia.org/wiki/Concrete_slab

 

[Neon Vagabond]

Concrete slab - Wikipedia - https://en.wikipedia.org/wiki/Concrete_slab

just checked the pictures, theres no slab, its right on the dirt.

Ive looked into to this >22k ohm scenario but what about if the guy is goin to be watering his plants in there, will that not increase the chances of it being under the 22

 

[buzzlightyear]

the guy wants a search lights, and 2 shot guns . He says he plans on putting a 11kw electric chair in there as well (plugged i

bright eyes ..

 

[Baddegg]

Concrete slab - Wikipedia - https://en.wikipedia.org/wiki/Concrete_slab

H aha ha aha you kill me buzz! Ha ha

 

[buzzlightyear]

just checked the pictures, theres no slab, its right on the dirt.

what ,now I'm now on the floor p**ing my self laughing .

 

[Dave OCD]

I'm sorry I don't know what else can be said.