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Old 03-29-2010, 12:43 PM
Dennis Hetland Dennis Hetland is offline
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First of all there is no such thing as 220/110 volt service in the US anymore. It's 240/120. Maybe that wiring diagram says it. If it does it must be really old.
Second the leakage from a solid state relay is micro and not the safety issue. The safety issue is that an ssr is a single pole switch and only opens one leg of the 240. This stops the flow of current through the elements, but does not isolate them. If you were to touch the element when the ssr was open and be grounded ( be touching something that was grounded at the same time) you would get hit with 120 volts at twice the current/amps that your annealer normally runs at. The ssr may be open, but the other end of the element is still tied to a wire that is tied to a breaker in a panel. So if you touch it you're touching the breaker.
I'm sure the MDR in the wiring diagram is a 2 pole which would break both legs of the 240 and isolate the elements from any electrical connection.
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