×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*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.

# Cable Calculations

## Cable Calculations

(OP)
I would like to know the complete procedure of carrying out cable calculatiions from the incoming transformer of an installation through a sub-distribution board, onto a number of distribution boards and finally down to final circuit, i.e. motors etc.. Can anyone help with a step by step procedure.

Many Thanks

### RE: Cable Calculations

Hi,
you have to start from the last load, find out the voltage level and divide the impedance so that u get current. Now, the easiest way is suppose you have five motors connected to a secondary of transformer.  I suppose that the motors rating is 35 A, 10 A, 40A, 100A, and 55A.  you have to select the cable of 1.25 % higher rating for safery purpose.  now in this case you have to use the cable of rating 45A, 12.5A, 50A, 125A, 70A cables. the cable from transformer to panel is tha addition of these cables, i.e. 302.5A.  I hope you got ur answer
Gaj

### RE: Cable Calculations

A good text is Beeman, Donald, Industrial Power Systems Handbook, McGraw-Hill, 1955 ISBN: 0070043019

Also, IEEE Standard 141-1993, Recommended Practice for Electric Power Distribution for Industrial Plants “Red Book” ISBN: 1-5593-7333-4

#### 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.

#### Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a partâ€™s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

# Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!