We also suffer from many summer storms. I have a whole house surge suppress=
or mounted at the breaker panel. Seems to work great. Obviously nothing wil=
l stop a direct strike. Mine is made by Eaton / Cutler-Hammer.  I can't fin=
d a picture/website for my model, but it is  basically like this one:

http://modusmodern.blogspot.com/2010/01/installing-whole-house-surge.html


On Feb 13, 2011, at 9:35 AM, Gerhard Fiedler wrote:

> Hello,
>=20
> We get our share of thunderstorms and lightnings around here, and I'd
> like to protect the electric supply of our home -- somewhere near the
> entry. The=20
>=20
> The supply is a three-phase system with a neutral wire (four wires) and
> the neutral wire is grounded (typically a grounding rod) at each
> connection point.
>=20
> Our connection point is at the property boundary, where the four wires
> come in from the street. As required, the neutral is grounded there and
> there is a master circuit breaker. This would be the first possibility
> to place overvoltage protectors, between the three phases and the ground
> rod (which is connected to the neutral).=20
>=20
> My question with this is whether this makes sense, considering that the
> neutral is connected to the same ground rod where I'd connect the
> protection devices -- and the neutral comes from the same "problem zone"
> where the 3 phases come from. But OTOH it's supposedly well grounded and
> probably already reasonably clean when it reaches my property. (I don't
> expect to have good protection if a lightning strikes within a few
> meters... :)
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>> From there, the four wires go through some 20 m underground to reach the
> house. There I have a ground rod for the protective earth wire in the
> installation inside the house (separate neutral and PE). This would be
> another place to put the protection devices (and I've seen quite a few
> installations that do this).=20
>=20
> However, I don't think I'd like to connect the protection devices to the
> protective earth grounding rod; after all, it's directly connected to
> many exposed surfaces all over the house. Connecting them to the neutral
> there would beg the same question as in the first option, with few if
> any advantages. (If a lightning strikes directly on the property, I
> don't think there's much that these protection devices can do anyway.)
>=20
> It's not easily possible to use a third ground rod that is far enough
> away from the other two. I'm tending to prefer the first option, placing
> the protective devices right at the entry point, and connect them to the
> neutral/ground connection there.=20
>=20
> Does anybody have any ideas what is the best solution here? What do you
> guys do for lightning protection?
>=20
>=20
> BTW, how would this earthing scheme be called? It seems it is a mixture
> between TN-C-S and TT. AIUI, it would be TN-C-S if I hadn't used a
> separate ground rod for PE and connected PE to the same ground rod where
> the incoming neutral is connected to, and it would be TT if the incoming
> neutral weren't grounded at each connection to the grid.=20
>=20
> The overvoltage protectors they sell for TN-S and TT systems have four
> protection devices, and the ones they sell for TN-C systems have three.
> Another question I have is how many overvoltage protection devices I
> need. I figure I only need three... no use trying to protect the
> combined neutral/PE wire that comes from the pole, since it is grounded
> anyway. Right?
>=20
> Thanks,
> Gerhard
> --=20
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>=20

Chris Smolinski
Black Cat Systems
http://www.blackcatsystems.com



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