I am replacing a 480v 3p chiller on a roof. It is currently being fed by a 800 amp breaker that is in its own enclosure next to the main service. It is tapped to the hot side feeding back to the TX. It feeds two conduits with 500mcm to roof. The new unit has a MOPD of 450 amps. Can i install a 600 amp fused disconnect with 450 amp fuses on the roof at the unit or must i install a 800 amp unit with fuse reducers to take my 450 amp fuses? john
under size disconnect
- Thread starter jociha
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LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
As I see it, according to Part II of Art. 440, you're okay.
450 x 115% = 517.5
450 x 115% = 517.5
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