Posted by Richard Miles at 22:28 on 2012 Jul 31
Hi Eric,Isn’t the problem not one of a domestic surge but from an electric surge through the ground loop and/or induced currents in conductors when lightning strikes nearby or some other electric storm is taking place?If you have an observatory some distance from the incoming electrical supply then it is good to provide a local earthing point(s) in which the resistance to earth is very low, e.g. a thick conducting metal rod(s) set a couple of feet into the ground, which itself is impregnated below with conducting metal powder that doesn’t oxidise or graphite powder.Also make sure that all kit including the telecope mount casing is earthed.CCD cameras can also be disrupted by induced currents.Richard