×
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

Can you use 105deg C medium voltage cable on 480V circuits?

Can you use 105deg C medium voltage cable on 480V circuits?

Can you use 105deg C medium voltage cable on 480V circuits?

(OP)
This is really a continuation of my other post asking about oversizing the motor leads beyond the NEC requirements to 250hp motor. I just want to look at all possiblilities. I checked but could not find any 600V cable that had an insulation rating of 105deg like medium voltage cable does...

There is nothing wrong with the 40 year old conductor now, the insulation of the cable is what has deteriorated. And that is the concern that that doesn't happen again.

The plant people still seem to think that oversizing the cable would be a good idea just because it would run cooler and like every thing else electrical prolong its life. If this is the concern, why not just get a higher rated insulation? I would think the higher insulation cost would be still much cheaper than increasing the amount of required copper by 50%.    


  

RE: Can you use 105deg C medium voltage cable on 480V circuits?

The cable will work, but I don't think it is cost effective.  The insualtion is a lot thicker so the outside diameter (OD) is bigger, taking up more room in the cable tray and conduits.  Larger raceways may be needed.

The medium voltage cable has a larger minimum bending radius  and needs more room for terminations, making installation more dificult.

A medium voltage cable will run hotter than the same size 600V cable due to the thicker insulation.  

An inpsector may still require the cable be designed to a 75 C rating for the terminations.

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