shunt trip

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john37

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If I have an enclosed shunt trip breaker within a room with an emergency power off pushbutton, do I need a shunt trip breaker at the panel as well? Please see attached diagram. Thank you.
 
John, if the designer designed it that way, the EC priced it that way, and the customer paid for it to be that way, well then, yes.

Obviously, the double ST's are redundant, but I don't know what decision the drawing is based on. Can you find out who does?
 
It will be interesting to see the answer to this one,,,,,,,,are we talking two mammograms machines or one with a parallel setup?

dick
 
I take it then the breaker within the panel does not have to be a shunt trip breaker? There are two seperate mammogram rooms that have an enclosed shunt trip breaker within each room. Each room has a separate emergency power off pushbutton to cut the power to each mammogram machine is seperate rooms. Sorry for my ignorance on this issue.
 
The only thing I can think of is a requirement by the clinic or hospital, for some reason,,,,,sorry I can't help I never had one:D,,,,,,, so really don't know what would happen if you couldn't deenergize the system.

Surely someone will come along and educate us.

dick
 
I've never provided a shunt trip at the panel if I've got an enclosed circuit breaker in the room that has shunt trip. Doesn't really make sense, and it would be a pain to reset for a typical hospital employee.

That being said, the documents do say to do it that way. Nothing wrong with it, other than an unnecessasry cost to the owner, imo.
 
It really does seem redundant to have to two shunt trips. I understand the one connected to the EPO, but what is the auxilary control for the one in the panel.
 
I see now they are both connected to the EPO. In that case: "John, if the designer designed it that way, the EC priced it that way, and the customer paid for it to be that way, well then, yes."
 
Looks like one of them is just in case the other failed, in the case of a radiation upset and dodging liabilities not a bad idea.

dick
 
john37,did you ever get a clarification from anyone has to their intent in designing it this way?

Just curious.

dick:confused:
 
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