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


HDPE conduit and cable thermal expansion issues

HDPE conduit and cable thermal expansion issues

HDPE conduit and cable thermal expansion issues

I'm looking at an application where some power and fiber optic cables are installed in HDPE conduit. Total length and ambient temperature fluctuation is such that the conduit will expand and contract by up to +/- 5m (15 ft). The cables inside will expand and contract at a much lower rate.

I'm looking for some references/advice on how this can be handled. The obvious thing to do is to leave some slack so that the cables can get pulled in and out of the conduit as the length changes. Some other issues arise though. The power cable has a splice which won't be able to handle as much tension as the rest of the cable. I'm not sure how to determine the tension in the cable when the conduit expands. The fiber will see compressive loads when the temperature drops possibly kinking it inside the conduit etc.

Has anyone done/seen anything like this done?

Any advice would be appreciated.

RE: HDPE conduit and cable thermal expansion issues

I would be more worried about the movement relative to the ground or anchor points. Once that is taken care of the cables will probably be okay. HDPE is not a stiff material so the restraining forces would not be high. Restraint in one direction will show as movement in the other directions (i.e, radial). The same conditions exist between copper conductors and wire insulation.

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!


White Paper - Effects of AIA Quick Guide to UL 489 or UL 1077
The function of a circuit breaker is to provide overload (thermal) and short-circuit (magnetic) protection to a circuit and its downstream components. A circuit breaker functions like an airbag in a car, protecting circuit components and people by tripping the circuit to interrupt the current flow if it detects a fault condition in the control system. Download Now
White Paper - Guide to Integrate Large-Format Additive
As with any new technology, getting into large-format 3D printing begins with investigation. The first question may be a simple one: what does “large-format” mean? For 3D printers, “large” is a relative term. Many extrusion-based (FFF) 3D printers are referred to as desktop machines, because they fit on table space. Some of these have very respectable build volumes – but when it comes to “large-format,” the machines will need their own dedicated floor space. Large-format 3D printers have significant build volumes and are most often found in professional settings, like manufacturing facilities and R&D centers. 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