On 04/09/2016 20:30, DICEGEORGE wrote:

why have two separate earths,

With feeds to outbuildings, there are times when it preferable to
separate the outbuilding's earthing system from the supplies.

It was a generic question about using non insulated CUs in cases where
one would have used insulated in the past - not specific to your OP.

one at the shed and one at the house,
why are they separate and not connected together?

Its not always straight forward. See:

http://wiki.diyfaq.org.uk/index.php/...rting_an_earth

That would be more fault tolerant.

With TT both ends, yup. With TN earth at the head end, it gets more
complicated.


--
Cheers,

John.

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