Parallel Feeders

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dpenbert

Member
Location
Missouri
I have a feeder (300A),(200ft) with (3)#350MCM & (1)#4 ground conductors (THHN), which should fit into 2-1/2" EMT.
If I don't quite have the room for the 2-1/2" conduit and would have an option of running two smaller parallel feeders, how do you calculate two alternate parallel feeders based on this information?

I know that running two smaller parallel feeders isn't more economical but if I have limited space I want to have an alternate option.

Thanks!

David
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Re: Parallel Feeders

Two sets of 1/0 CU would do it.

Each set in a 1.5 " or 2" EMT.

You will need a 4 AWG EGC in each raceway, if you choose to run one,

[ December 30, 2004, 03:51 PM: Message edited by: iwire ]
 
J

jtester

Senior Member
Location
Las Cruces N.M.
Re: Parallel Feeders

Bob
Could you go over your calculation for us. I come up with #1 Cu as long as we have 75 degree connections at both ends. I'm not sure how we would have another condition.
Thanks
Jim T
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Re: Parallel Feeders

Jim I agree that 1 AWG would do it if the load was less than 260 amps.

The opening post did not specify the load, only the feeder size. Given only that info 1/0 is a safe call IMO. :)

There is another issue that makes 1/0 the only option.

310.4 only allows parallel conductors of 1/0 or larger. There are some exceptions, none that would apply to this installation.

Bob

[ December 30, 2004, 05:08 PM: Message edited by: iwire ]
 
L

lady sparks lover

Senior Member
Re: Parallel Feeders

I'm not trying to open the discussion, but the voltage drop will be different for 208V and 480V, because the higher the voltage the less impact that voltage drop has. So are you saying 208V or 480V or other? If you have 480V, paralleling the conductors without increasing for voltage drop might work if 208V you might have to bump it up. It all depends on the voltage. Just a question... :)
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Re: Parallel Feeders

Originally posted by lady sparks lover:
I'm not trying to open the discussion, but the voltage drop will be different for 208V and 480V, because the higher the voltage the less impact that voltage drop has.
Click to expand...
Open it that's what we are here for. :)

I did not consider voltage drop at all for a couple of reasons.

1)The OP did not ask about it.

2)We do not know the load, it is unlikely a 300 amp feeder has a 300 amp load connected to it.
 
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