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When to use UL 489 or UL 1077 CB's

When to use UL 489 or UL 1077 CB's

When to use UL 489 or UL 1077 CB's

Greetings all.

I have a couple questions and am hoping I can find help with my issues here.

The first (and main) issue is when to use a UL 489 CB vs a UL 1077 CB. I have a document from SQD that has a good outline on when to use them, but I'd like some clarification on this. (See Page 2 of this link) What we're trying to clarify is, say you have a 480V feed coming into a control panel. This 480V feed goes to a 480/120 TX and there is a UL 489 CB on the secondary side of the TX, followed by a series of UL 1077 supplemental protection CB's. Can a UL 1077 CB be used to feed a small pump (like a chemical dosing pump, for example) that plugs in to a receptacle? I'm thinking this would be an inappropriate use of the 1077 CB, but I'd like clarification.

The second issue is, if the above is true (i.e. a UL 489 CB must be used in this case), has this ALWAYS been the case or is this a change in the code that's happened within the past few years? We've had this brought to our attention recently and we've had a few panels go out with UL 1077 CB's feeding small pumps. Consequently, if this is not allowed per code, we have to make provisions to get these changed out.

Thanks in advance!

- C

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