Sizing parallel feeders

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melanconelectric

melanconelectric

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Location
West Monroe, LA
Installed a 100KW Generac at a restaurant and ran 500 to it. Lugs from factory only for 400, Generac says MUST use those lugs on THAT breaker. Supplier says we may can get some crimp on studs that will lug into those lugs. Pull is only less than 30', cant I just re-pull with parallel sets? If so, how do you size parallels... 4/0? 300? 3/0?... is there a chart or table?

EXISTING: 3 #500 in 3 inch pvc (1PH)
 
360Youth

360Youth

Senior Member
Location
Newport, NC
Check your Art 310 (NEC is in the truck, so I do not have exact article) on paralleling conductors and what is required (Size, material, etc.). Total ampacity of paralleled individual conductors must equal that of calculated load and/or OCP.
 
iwire

iwire

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Staff member
Location
Massachusetts
melanconelectric said:
Installed a 100KW Generac at a restaurant and ran 500 to it. Lugs from factory only for 400, Generac says MUST use those lugs on THAT breaker. Supplier says we may can get some crimp on studs that will lug into those lugs. Pull is only less than 30', cant I just re-pull with parallel sets? If so, how do you size parallels... 4/0? 300? 3/0?... is there a chart or table?

EXISTING: 3 #500 in 3 inch pvc (1PH)
Click to expand...

First question, why not just repull it with 400s?

Second question, are the lugs on the breaker rated for parallel conductors?

Third question, 100 KW at what voltage? I see (1PH) so should I assume 120/240 for 416 Amps?

Forth question, what size breaker?


Can't tell what you need for a conductor without knowing the output current and breaker size.
 
melanconelectric

melanconelectric

Member
Location
West Monroe, LA
iwire said:
First question, why not just repull it with 400s?

Second question, are the lugs on the breaker rated for parallel conductors?

Third question, 100 KW at what voltage? I see (1PH) so should I assume 120/240 for 416 Amps?

Forth question, what size breaker?


Can't tell what you need for a conductor without knowing the output current and breaker size.
Click to expand...

Lugs are rated for parallel ( 3 openings on each); yes 100kw at 120/240 1ph; genset is rated for 417 amp output (natural gas unit); breaker size is 450 amp
 
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