Another thought is that Lightning damage attributed to Mains strikes are
often not the result of a strike on the AC mains at all but rather Near
strikes on nearby Trees or direct - Secondary strikes to houses, buildings
etc.
I think one of the biggest ironies is that folk are used to assuming that
equipment is susceptible to Lightning damage from the AC mains and the
'surge arrestor' industry hyes this expectation up so that when equipment
does suffer Lightning damage it is often assumed that the damage came in via
the power system so that little or no investigation is carried out as to
where the Lightning strike actually occoured.
I Believe that the main reason for the minimisation in Lightning damage from
the MEN mains is that the multiple Earths provide what is probably the best
Earthing system that it is possible to get at (relatively) low cost - in
fact Radio and Tv transmitters try to achieve the same thing by using
multiple earth stakes over often 1000 square meters or more and even they
suffer Lightning damage from time to time.
Yep that pretty well Sums it up !
- posted
17 years ago
