woolf
Member
- Location
- Los Lunas NM
Whats the best wire size for a 200 amp 3 phase service run of 470Feet
Wire Sizing
- Thread starter woolf
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petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Best for who?
Al or Cu?
What is the calculated load?
What is the actual load?
Do you care what the voltage drop is?
Is it really a service, or is actually a feeder?
Last edited:
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
What is the "best"? That is subjective, and there are many factors that must be taken into account. Do you want copper or aluminum? Do you want to take advanage of a transformer secondary tap to raise the voltage, and therefore not have to worry so much about voltage drop at the load end? Is this service going to supply an entire dwelling unit, so that table 310.15(B)(6) applies? Is this a dwelling unit at all? Is price an issue? Is availability from local suppliers an issue? Is the service going underground or overhead? Much goes into the notion of "best." More information is needed.
Welcome to the forum.
Welcome to the forum.
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
No fair, Bob. :happysad: I was typing when you posted. I should have waited until I had my answer ready, before approving the original thread. :lol:
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
cheater!
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
That would not be cheating, Bob. Cheating would be to use my status as a moderator to delete your first post, so as to make it look like I had responded first. :lol:
woolf
Member
- Location
- Los Lunas NM
Service for a future tenant
woolf
Member
- Location
- Los Lunas NM
:slaphead: Sorry everyone for not giving enough information. I had a customer come ask the question. the info given was very slim but he is trying to run 350al @ 470' for a 3 phase 200amp panel to feed a future use of winery and the load is unknown but the customer is only wanting 200amp panel no more or less.
With out knowing the actual load the 350KCMIL AL may or may not be sufficient. I am not familiar with what type of coolers and other loads are in winery's so I couldn't make a very good guess.
Roger
mayanees
Senior Member
- Location
- Westminster, MD
- Occupation
- Electrical Engineer and Master Electrician
woolf,
You're still missing a critical piece of data - the operating voltage!
If it's 240 V, 3 phase, you'll get a 5% VD at ~ 60 kW with 470' of 350 AL. 480 V yields ~ 240 kW.
For a more realistic VD of 2.5%, halve those kW numbers.
Keep in mind that design recommendations are 5% overall, but they are just recommendations and are not enforceable. It's best to have some idea of the user, because the type of load will dictate the VD tolerance. Motors will have inrush characteristics that could dip the voltage excessively during startup, which could be prohibitive, in the case of, say a fire pump, which per 695 can't have more than 15% VD on startup.
You're still missing a critical piece of data - the operating voltage!
If it's 240 V, 3 phase, you'll get a 5% VD at ~ 60 kW with 470' of 350 AL. 480 V yields ~ 240 kW.
For a more realistic VD of 2.5%, halve those kW numbers.
Keep in mind that design recommendations are 5% overall, but they are just recommendations and are not enforceable. It's best to have some idea of the user, because the type of load will dictate the VD tolerance. Motors will have inrush characteristics that could dip the voltage excessively during startup, which could be prohibitive, in the case of, say a fire pump, which per 695 can't have more than 15% VD on startup.
kingpb
Senior Member
- Location
- SE USA as far as you can go
- Occupation
- Engineer, Registered
1 conductor per phase utilizing a 350KCMIL aluminum conductor will limit voltage drop to 4.81% or less when supplying a 200A rated panel loaded to no more than 160A after 470ft, on a 208V 3phase system.
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