What's inside an SPD?

[ban-all-sheds]

I don't really get ....

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At least in my part of the world (and I would imagine countless other 'rural' locations), I feel that LPAH alone is often going to be far more than 1 km. I've never bothered following the overhead 11 kV feed to my village to see where it originates, but it's certainly 'quite a long way away'

Kind Regards, John

That gives rise to another question, consideration of which makes you wonder if "they" didn't think this through properly.

If (LPAL + LPCL + LPAH + LPCH) is limited to 1, but you do know all of the values, and they total more than 1, which one(s) do you reduce in order to make the total 1 before you plug them into (2LPAL + LPCL + 0.4LPAH + 0.2LPCH) ?

 

[SimonH2]

When there's a choice of options like that, the traditional answer is "are you buying or selling ?"

 

[ban-all-sheds]

I wonder if the answer is "Never mind the calculation, unless you live in a very low ground flash area or an urban one, you're going to need* an SPD".



* Subject to financial viability if it's a domestic dwelling.