×
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

magnetic duct

magnetic duct

magnetic duct

(OP)
For the purposes of short circuit calculations does anyone know if teck cable is considered 'magnetic duct' (due to the fact that it is encased in metallic armor)?

RE: magnetic duct

Steel armor - yes; aluminum armor - no.

RE: magnetic duct

The type of raceway may not have significant impact in the SC rating of the cable. This mainly is a function of the insulation withstand temperature (initial & Max.), the conductor material and the duration of the SC (protective device tripping characteristics).

The enclose link will help to illustrate the SC effect on cable.

http://cuky2000.250free.com/Cable_SC_IEEE-Std-242.jpg

RE: magnetic duct

(OP)
I'm not concerned about the SC rating of the cable in this case - I'm am modeling an existing system and am only concerned with how the magnetic duct effects the cable impedance and hence the downstream short circuit.

RE: magnetic duct

For practical purposes, resistance is unaffected by the conduit or armor material (magnetic or nonmagnetic). However, cable reactance may vary significantly if compared with single conductor cables installed in conduit. A rough approximation may be estimated as follow:
  a) For nonmagnetic armor consider approx 20% less reactance than 3 single conductor in magnetic conduit.
  b) For magnetic armor, consider approx 50% less reactance than 3 single conductor in magnetic conduit.

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