×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

electrical cable sizing for 3 phase

electrical cable sizing for 3 phase

electrical cable sizing for 3 phase

(OP)
anyone have the formula to select the cable size for a 3 phase line.

info i have

3 phase 460v
3 - motors... 8.9A, 8.9A, 13.2A
1 way distance of 2480'
 

RE: electrical cable sizing for 3 phase

Google search for voltage drop calculators.

Also half a mile long 480V circuit is a bad idea, but that was not your question.

RE: electrical cable sizing for 3 phase

(OP)
why is it a bad idea.. most sites dont give me a formula so thats why im asking here

RE: electrical cable sizing for 3 phase

Using the simple calculator that I have, I came up with a ~5% voltage drop along for a 4/0-cable with (31A load). This is right at the critical voltage drop according to IEEE Std. 141 so any other loads will only make it worse.

Also, motor starting might become an issue. I would recommend modeling your circuit in either ETAP, SKM, or EasyPower to determine the best design.

RE: electrical cable sizing for 3 phase

Take a deep breath. I am in worse mood than you are today.

It is just too long a circuit at that voltage. You will see when you do the calc. I am not saying it won't work.

If you are really designing something you need to make an effort to learn some basics. This site is not here to teach basics to novices. There are schools for that purpose. This is a forum for "professionals" to bounce off ideas and benefit from each other's experience. Not to learn basics.

Search a little harder or buy/borrow basic electrical engineering book/hand book. Even try Ugly's handbook.

If you keep this attitude, it will not be long before your post disappears from this site!

 

RE: electrical cable sizing for 3 phase

We usually don't use a formula for this type of issue. We look it up in tables and extrapolate if we have to.
Why is it a bad idea? High cost and poor performance. Consider transformers and a higher voltage.  

Bill
--------------------
"Why not the best?"
Jimmy Carter

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources