> "The only possible reason I can think of for people to say that is that sometimes the MOVs can damage themselves in the event of a surge. They become sacrificial devices - if they fail, replace them. Yes, MOVs should be always be enclosed, so should they explode when they fail, bits do not go flying just anywhere."
In the context of utility line surge suppression, MOVs should only be used at the service entrance (i.e., utility meter and/or service entrance panel). If MOVs are used on a branch circuit, they should only be used between line and neutral. Neutral is the grounding conductor actually designed to carry current -- not ground. We'll never get past the belief that "all three modes of protection" is a good thing. I was once a believer myself until recently, having installed expensive Leviton hospital-grade receptacles in the shack with built-in "three modes of surge protection." Even IEEE literature continues to condone these devices. The dilemma becomes clearer when you draw the electrical distribution on paper and examine the potential surge flow. Arguably, a more effective method of diverting a surge on a branch circuit is to *store and bleed* the surge to neutral. These units cost much more than a single MOV when used from line to neutral but there's also more propensity of blowing the MOV rather than the bleeding type of single-mode surge suppressor. Paul, W9AC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
