Earth Pit Sizing - 1MVA Transformer and 7.5MVA Power Transformers

not an exact answer but will be of help probably..as long a as your total impeadance of your earthing elements will not be greater than 1 ohm..

Yo Guest For each transformer you have to make a separate earthing These earthings have to be EACH < 0.2 Ohms The distance between each of other (pit) has to be at least the longest distance as the drilling length of the deepest earthing. These earthings have to be each separately connected with each an intermediate busbar to each starpoint of each transformer. Further info http://www.leonardo-energy.org/earthing-systems-fundamentals-calculation-and-design TTYL: ciao T L ;)

Which country are you from? Then I will guide you properly.

For a fee

Not necessarily! Had I started charging a fees for my answers in such forums, I would have been a millionre by now.

This is their homepage

http://www.leonardo-energy.org/

Maybe because of a lousy earthing of your lowvoltage systems you haven't got access to static cloud computing ;)

Further I don't don't feel any needs nor do I strive for perfection

I work and live according to the QS-9000

some call it the ISO 9001

In those global specifications are these values mandatory.

L8rz.. T L

Timelord and anyone else

I am not being critical about the process I am just asking a question. I have plenty for access to lightning strikes. Forgetting about QS-9000 and ISO 9001, why do you feel it is good engineering to try for such a low resistance value?

Yo Wareagle

I survived a lightningstrike in 1972, so don't talk to me about plenty Lightning

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We all are lured in a Digital existence since 1986 (S.W.I.F.T. bankingsystems)

Your world is maybe now on a size of nanoscaling (10^-6)

You might even have already troubles with mind over matter

We work with values on petascale (10^-15) (see f.e. FRAM memory)

Consequence :you have to be PRECISE, ACCURATE and follow the RULES !

Then even thoughts can create energy.

If the (production)personnel of BP had .NOT. ignored the rules of the QS-9000,

by switching OFF the offshore F&S alarms and then gone sailing,

OUR people would still be alive and no colossal oilspill would have happened @all.

L8rz.. T L