Is There Alternating Current in Harry's World?

[justcorbly]

No: HPFGUIDX 184175

Somewhere, in DH I believe, one of the characters makes a comment about radio that 
revels, at least to me, that he's pretty unfamiliar with it.

So... is Hogwarts off the grid?  What about all the other houses and buildings that our cast 
of characters inhabit or shelter in?

If there's no use of electricity and all the conveniences that depend on it, why?  Does 
electricity pose a threat to wizards and witches? Are their kitchens powered with wood-
burning ovens?  What about refrigeration?

Are their homes completely and always invisible?  If not, how do they avoid things like 
council taxes or property taxes?  If they don't, how do they get the money to pay?

Do they shop at the local grocery?  Use credit cards?

Are they all in the NHS?

Come to think of it, what's the local school system's response when 12-year-olds 
suddenly drop out of school?  Is Hogwarts on the UK's list of accredited private schools? 
What if a someone like Hermione wants to pursue work at university?

Just asking.  I know that quick answer is "magic", but that's cheating, I think.

justcorbly