On Thu, 12 Apr 2007 05:34:42 -0400, "Roger Long"
wrote:

Isn't there something that could be inserted in the feed to the
instruments that would restrict voltage spikes?

Yes, it's called a zener diode and they come in different voltage
ratings.

http://en.wikipedia.org/wiki/Transie...pression_diode

http://www.electronics-manufacturers...rotectors.html