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!

*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.

Jobs

Connecting different sized cables

Connecting different sized cables

(OP)
Just wondering how everyone would connect a 120mm2 2C+E cable (Cable 1) to a 16mm2 cable 2C+E(Cable 2). Cable 1 is from the switchroom (upstream CB is 32A) to a remote room (very long run I have been told) and is 120mm2 for volt drop. Both cables are copper. Once Cable 1 enters the remote room, it needs to connect to Cable 2 to power a cabinet, with loads of 16A or less. I was thinking of a junction box with an isolator or something along those lines? How does everyone usually connect cables that are so different in size?

RE: Connecting different sized cables

Terminal box with stud or busbar feedthrough terminals? Resin joint with bolted lugs?

RE: Connecting different sized cables

Isn't it a requirement that if changing cable sizes it has to be done via some downstream protective device(fuse, breaker) is downstream cable is smaller CSA than upstream.

RE: Connecting different sized cables

that depends upon whether the upstream protective device is sized to protect the smaller cross section cable, which is entirely possible if the larger cable is only oversized for volt-drop rather than for loading. In this case I would say that a 32A breaker protects both cables from a thermal perspective, but it is indeterminate from the information provided whether or not that breaker is adequate to meet disconnect times for short-circuit and earth fault.

RE: Connecting different sized cables

Or it might fall under a tap rule.

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


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