500kcmil vs parallel 3/0

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Jps1006

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We have a 400-amp 208 overhead service to replace. I tend to see most 400-amp services done in 500kcmil with 3 or 3-1/2 pipe. I don't see a lot of 400-amp services done with parallel 3/0. What are most of you doing? 500cu is over $6/ft and 3/0 is well under $3/ft. I hate trying to man-handle 500 especially in cool weather. Why do I see so many 400- amp services done in 500? Is it just to keep it down to one pipe?
 
I have done many 400 amp services but never overhead. If this is a residential job then you can still use one conduit and parallel your conductors. 3/0 would than have a final ampacity of 180 amps which would still allow you to use as 400 amp as long as the calculated load is only 360 amps or less.

Parallel 4/0 would be required for the full 400 amps. I agree with you I would hate to work with 500's but you may want to do a cost difference. If you need to go thru the roof then I would only want to do that once
 
500 kcmil would be my choice. Less raceways + less terminations = less work. Shaping 500's isn't very difficult but it does require some finesse and more skill.
 
If you needed 2 raceways then it wouldn't be worth it. 400 amp services for homes use the 400 amp meter base and that only has one hub. I would not want to add a wireway.
 
Turns out we may be attaching the aerial cable to the mast to get the cable high enough for truck traffic, so probably going with the single conduit for that reason.
Although I would argue (2) 2" conduits (IMC $3.77/ft) vs 3.5" (IMC $11.45/ft) and double the 3/0 wire ($2.21/ft) vs 500MCM ($6.59/ft) cheaper in material (didn't even price the weather head yet!). Working the heavier material would slow me down vs. double the terminations.

Dennis, good idea parallelling 4/0 all in the same pipe. Didn't think of that.
 
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Because of all the reasons posted.

Another one maybe not worth considering at stated voltage/size: what is the short time/instantaneous withstand of (1) 500 vs (2) 3/0. Forget 380A vs 400+ long term ampacity for a second and think about it.
 
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