At first glance,

1. capacitance from earth to each of the other two pins.

If either side of the switch is stuck closed, I would expect greater
capacitance to earth from either phase or neutral.


2. mutual inductance to nearby coil

If either side of the switch is stuck, effectively a longer wire exists
as either phase or neutral is joined to the element, and it should be
possible to detect this greater inductance, which will have a lower
resonant frequency, by using a dip oscillator.


My little offering.....

Regards, Kevin

__________________________________________________
Do You Yahoo!?
Everything you'll ever need on one web page
from News and Sport to Email and Music Charts
http://uk.my.yahoo.comm

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu