My dad's greenhouse

[La Poste]

I have been reading a little about bonding and outbuilding supplies and have just had a thought.

My father has a metal framed greenhouse with a socket inside supplying a heater.

The heater is metal and the socket is metal clad.
The supply is TN-S and I am not sure of the loop impedance, I can measure it tomorrow.
From what I have read I am now of the opinion that this metal frame should be bonded back to the MET in the house.

I can use the adiabatic to work out the size of bonding conductor.

The greenhouse is made primarily of glass but with a steel frame.

The other thing is the supply is an underground lead sheathed TN-S cable that runs about half a mile to a transformer on a pole in the field out back.
There is so much of the metal sheath connected to true earth on the long run back that it kind of acts like an enormous earth plate if you know what I mean.
The lead sheath is then connected to the transformer which itself has a long earth cable going into the ground.

Do you think this greenhouse needs bonding?

Thanks.

P.S. one more thing, the ground is clay and very damp and soft, if a TT were installed I would imagine a very low reading could be obtained.

 

[telectrix]

IMO, Yes, unless you can IR test from the metal frame to the MET and get a reading of >22Kohms.

 

[La Poste]

Here's the transformer:

 

[telectrix]

and here's another...

 

[La Poste]

And the underground cable taken a while back whilst digging the garden:

The cable is the one on the right.

 

[Knobhead]

OK I’m being facetious here. TT it with a spike at each corner, it’ll keep it tied down when it’s blustery.

I’ll never forget how upset my father in law was when the wind took his beloved green house. “Stuff the greenhouse, what about my chrysanthemums!” The only year in all the time I’ve known him he didn’t win a prize for them.

 

[GLENNSPARK]

i hope your not suggesting tent pegs for rods here Tony..lol...i can see at least 1 forum member coming over the hill already..lol....."you wont get a decent Ra with that"!!!.....

 

[trev]

Nah, 4 tent pegs with a continuous cable connecting them what could possibly go wrong?

YYYYYEEEEEEEHHHHAAAAAAAAAAAAAAAAAA

 

[GLENNSPARK]

bit of 1mm cpc....or whatever turns up in the greenhouse after a quick rummige...some wire garden twine maybe....it`l do.......