2 Sets of feeders in one conduit

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I am assuming you’re using 3/0 and you can only fit 8 3/0 widres in a 2 1/2” conduit. Secondly if you’re running it a neutral it will only allow you 70% ampacity after derating which will be about 158 amps.

In my opinion I would run two separate 2” conduits and not have to worry about derating. If you’re running it without a neutral you could use 80% and would ha e “180 amps after derating.


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ElectricMatt said:
I am assuming you’re using 3/0 and you can only fit 8 3/0 widres in a 2 1/2” conduit. Secondly if you’re running it a neutral it will only allow you 70% ampacity after derating which will be about 158 amps.

In my opinion I would run two separate 2” conduits and not have to worry about derating. If you’re running it without a neutral you could use 80% and would ha e “180 amps after derating.


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appreciate the info, we have an existing 2 1/2 emt. I completely didn't even think about derating we will run another 2 1/2 conduit I find it's a lot easier to run 3/0 in 2 1/2.

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JMWElectric said:
appreciate the info, we have an existing 2 1/2 emt. I completely didn't even think about derating we will run another 2 1/2 conduit I find it's a lot easier to run 3/0 in 2 1/2.

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Depending on the length of the 2 1/2" EMT.
Compare the differences in material cost, and labor cost of installing two new conduits compared to the cost of using compact type 4/0 XHHW cu for the 6 phase conductors for the two feeders, and 3/0 XHHW cu for the two neutrals and using the existing 2 1/2" EMT conduit. (Added labor pulling the wire? Number of bends in the existing conduit?)

Table C.1(A) chapter 9 shows 8 compact type 4/0 XHHW in a 2 1/2" EMT conduit.

70% of 260 amps = 182 amps. Roll up to 200 amp breakers.

Just a thought.
 
Jamesco said:
Depending on the length of the 2 1/2" EMT.
Compare the differences in material cost, and labor cost of installing two new conduits compared to the cost of using compact type 4/0 XHHW cu for the 6 phase conductors for the two feeders, and 3/0 XHHW cu for the two neutrals and using the existing 2 1/2" EMT conduit. (Added labor pulling the wire? Number of bends in the existing conduit?)

Table C.1(A) chapter 9 shows 8 compact type 4/0 XHHW in a 2 1/2" EMT conduit.

70% of 260 amps = 182 amps. Roll up to 200 amp breakers.

Just a thought.
Click to expand...
6 4/0 xhhw and 2 3/0 thhn would fit in 2 1/2?

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That is an interesting idea. I forget about the compact and I didn’t realize the XHHW had a higher ampacity. That’s a good tip for the future.


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JMWElectric said:
is this xhhw-2?

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A quick search on Google I found this.
http://www.prioritywire.com/specs/Copper XHHW.pdf

1-877-611-5122

Priority Wire & Cable, Little Rock, AR PWC-2013
Copper XHHW-2 600V XLPE Insulation

Application:
XHHW-2 cables are primarily used for power distribution. XHHW-2 cables may be used in wet or dry locations, with ambient temperatures not exceeding 90°C. Voltage rating for RW90 cable is 600V.

Conductors:
XHHW-2 conductor is a compact soft drawn bare copper with class B stranding per ASTM.

Insulation:
XHHW-2 has abrasion, heat and moisture resistant cr
oss-linked polyethylene insulation XLPE.



FYI compact type wire is more common with aluminum conductors than copper.
Like I said for 4/0 XHHW copper you will need to check for availability.

The 3/0 XHHW for the neutral conductors does not need to be compact type.

.
 
ptonsparky said:
Using an LB? Check the fill capacity for it. They are usually less than that of the raceway.
Click to expand...

IF the OP has to use an LB I would use a Mogul LB and increase the size of the LB to 3". He will use 3" to 2 1/2" RE bushings.
The more room the better for the wire installation. The labor saved, (time is money), should pay for the additional cost of the 3" Mogul LB and two RE bushings.


https://www.garvinindustries.com/fi...ron-conduit-bodies/aluminum-mogul-lb/molb-300


http://www.emersonindustrial.com/en...x_Series_C_LB_UB_and_LL_LR_T_Mogul_Bodies.pdf
 
Jamesco said:
A quick search on Google I found this.
http://www.prioritywire.com/specs/Copper XHHW.pdf

1-877-611-5122

Priority Wire & Cable, Little Rock, AR PWC-2013
Copper XHHW-2 600V XLPE Insulation

Application:
XHHW-2 cables are primarily used for power distribution. XHHW-2 cables may be used in wet or dry locations, with ambient temperatures not exceeding 90°C. Voltage rating for RW90 cable is 600V.

Conductors:
XHHW-2 conductor is a compact soft drawn bare copper with class B stranding per ASTM.

Insulation:
XHHW-2 has abrasion, heat and moisture resistant cr
oss-linked polyethylene insulation XLPE.



FYI compact type wire is more common with aluminum conductors than copper.
Like I said for 4/0 XHHW copper you will need to check for availability.

The 3/0 XHHW for the neutral conductors does not need to be compact type.

.
Click to expand...
I can use xhhw-2 aluminum correct? it's rated at 205 amps 90c

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never mind this won't be enough.

this xhhw is about 1$ more per foot and I'll end up having to replace existing feeders I'd probably spend a bit more but less headache. thanks for all your help guys.
 
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