Contact US

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!

*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

PE Cable placement in cable ladder

PE Cable placement in cable ladder

PE Cable placement in cable ladder


In a system with a large motor supplied by a converter.
The cabling is three phase with a PE conductor.

In the cable tray/ladder from the converter to the motor, Where should the PE conductor be placed?

As close the phase cables as possible, in the same cable tray as the cables, or as far way from the phase cable to prevent induced voltage in the PE cable.

From https://www.electrical-installation.org/enwiki/Con... i can read that:
"In IT and TN-earthed schemes it is strongly recommended that PE conductors should be installed in close proximity (i.e. in the same conduits, on the same cable tray, etc.) as the live cables of the related circuit. This arrangement ensures the minimum possible inductive reactance in the earth-fault current carrying circuits."

Should this prioritized, and thereby ignore the losses induced in the PE cable at nominal run?

RE: PE Cable placement in cable ladder

Ignore the losses and put the PE as close as possible.
I remember seeing a recommended cable construction for VFD condustors.
It was 7 core cable. The center core was a PE and the surrounding cores were arranged; PE, A, PE, B, PE, C.

Ohm's law
Not just a good idea;
It's the LAW!

RE: PE Cable placement in cable ladder

Thats what i thougt thanks.

The losses wont affect the current in the phase cables right?
It will only be dissipated as heat in the PE cable, which should be able to withstand it?

RE: PE Cable placement in cable ladder

The losses are related to frequency. The higher order harmonics tend to induce more current in the PE.
But the higher order harmonics tend to be lower amplitude and trapping some of the harmonically induced losses in the cable somewhat mitigates the losses due to harmonics in the motor.

Ohm's law
Not just a good idea;
It's the LAW!

RE: PE Cable placement in cable ladder

Thanks for your answer,

So as i understand it, the losses gained from laying the PE close to the phase cables will almost never outweigh the gained harmonics/common mode reduction?

RE: PE Cable placement in cable ladder

I am going to wait awhile and see if jraef comments.

Ohm's law
Not just a good idea;
It's the LAW!

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! Already a Member? Login


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
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’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:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close