Parallel conductor sizing inside disconnect

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swei

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I'm bringing feeder duct into an 800A fused disconnect via a flanged end. Conductors will link these lugs to the disco switch lugs, possibly passing through a CT cabinet on the way. They will not be in conduit (other than a possible pair of 4" nipples if the CT cabinet is used.)

Are these considered to be in a raceway, or free air, or something else entirely?

310.16 asks for a lot more copper than 310.17 does, and I don't think there is any 75?C limitation on bare lugs.

thanks...
 
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chris kennedy

chris kennedy

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Location
Miami Fla.
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60 yr old tool twisting electrician
Lets say you 2 sets of 500's in your feeder duct. You want to change to a smaller size in your disco? You have 90?C lugs in said disco?
 
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swei

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Just looked inside and found out that the disconnect is labeled "Use 75 degree conductors" which I'm interpreting to mean that the terminals are indeed 75C.

Feeder is not wire, it is bus duct (technically feeder duct, which has no plug-on openings and is 3R rated.) The flanged ends have lugs which will protrude into the disconnect cabinet. Conductors will be roughly 30" in length, unless we use the CT cabinet, in which case they might be 5 feet or so.
 
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