gEDA-user: earth ground & EMI

[DJ Delorie]

> You would only want filters in the ground terminals in the case that ground wire 
> went out over open ground and was susceptible to lightning strike transients. 
> for the furnace system, some transient suppressors on the power wires should be 
> enough.

The wires are 18 gauge unshielded cables, up to 60 feet long, running
through the house.  They all pass near the electrostatic filter, which
is basically a small lightning generator.  The current board will
glitch the furnace relays and LCDs when the electrostatic filter
sparks.