Parallel SE cable

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Tim Brda

New member
Location
Fenton, Mo.
Is it permissable to parallel two 4/0 SE cables from the load side of a meter enclosure to a 400 amp SE rated transfer switch. This is a residential application.
 

raider1

Senior Member
Staff member
Location
Logan, Utah
Welcome to the forum.:)

Yes, provided that you follow all the rules located in 310.10(H) and the calculated load does not exceed 360 amperes. (Assuming that you are on the 2011 NEC)

Chris
 

jumper

Senior Member
IMO, no. 310.15(B)(7) 2011 NEC makes no mention of a parallel connections of feeders in this application.

(7) 120/240-Volt, 3-Wire, Single-Phase Dwelling Services
and Feeders. For individual dwelling units of one family,
two-family, and multifamily dwellings, conductors,
as listed in Table 310.15(B)(7), shall be permitted as
120/240-volt, 3-wire, single-phase service-entrance conductors,
service-lateral conductors, and feeder conductors

that serve as the main power feeder to each dwelling unit
and are installed in raceway or cable with or without an
equipment grounding conductor.
 

raider1

Senior Member
Staff member
Location
Logan, Utah
IMO, no. 310.15(B)(7) 2011 NEC makes no mention of a parallel connections of feeders in this application.

(7) 120/240-Volt, 3-Wire, Single-Phase Dwelling Services
and Feeders. For individual dwelling units of one family,
two-family, and multifamily dwellings, conductors,
as listed in Table 310.15(B)(7), shall be permitted as
120/240-volt, 3-wire, single-phase service-entrance conductors,
service-lateral conductors, and feeder conductors

that serve as the main power feeder to each dwelling unit
and are installed in raceway or cable with or without an
equipment grounding conductor.

But if I use the ampacity of 4/0 aluminum from Table 310.15(B)(16) which would be 180 amps before any adjustment factors I would not have to go to 310.15(B)(7). 310.15(B)(7) is not a mandatory section it just relaxes the general rules for overcurrent protection for dwelling unit services.

So provided that the calculated load does not exceed 360 amps I can use the next size up rule of 240.4(B), as allowed in exception No 2 to 230.90, and use a 400 amp OCPD at the service disconnecting means.

Chris
 
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