[sdiy] Isolation transformer question..

[Steve Begin]

This is not _quite_ related but a few months ago lightning struck near my
girlfriends house and it ruined their network hub and 3 ethernet cards (and
a printer?) but the computers seemed to survive the ordeal fortunately.  I
just wanted to mention that, since it hadn't occured to me to protect
against power surges coming from my internet connection. 

> Steve Begin


-----Original Message-----
From: J. Larry Hendry [mailto:jlarryh at iquest.net]
Sent: Sunday, July 21, 2002 10:15 PM
To: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] Isolation transformer question..


Amen.  The ONLY perfect lightning protection is disconnection.  I'll take it
Harry's 2 pole switch is for 120 only.  I have a 3 pole switch on my studio
feed since I have a 240 volt circuit (common 3 phase device about $35).
But, the common point here is don't forget to switch off the neutral.  In my
opinion, more lightning damage is caused by step potential induced neutral
voltages that go high in reference to actual ground than spikes that
actually come in the hot line.  That transformer that feeds your house
should have a surge arrestor on the primary that clamps at about 110% and
itself a fairly decent filter to high frequencies.  So, hot leg only
switches are useless IMO.  Of course, the isolation transformer makes a huge
difference.  But, neutral disconnection is often overlooked.

Larry (who could go on forever about bad residential grounding techniques
that allow most lightning damage).

----- Original Message -----
From: harry <harrybissell at prodigy.net>
Get a huge double pole toggle switch (mine is a 30A / 120VAC) and switch
both sides of the incomming line to off when you leave the studio... it
should protect the gear from most everything (when off) including small
lightning strikes.
H^) harry