×
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

Wire termination temperature mismatch

Wire termination temperature mismatch

Wire termination temperature mismatch

(OP)
I need to make connection to equipment with flying leads (special high temp wires rated for 150 deg.C ampacity).If I need to use NEC 75 deg.C rated wires connected to that equipment, what would be the best way to reduce temperature to 75C level? May be use a piece of copper bar between those two wires and trying to estimate the temperature gradient (decline) along the bar length? Please advise.

RE: Wire termination temperature mismatch

I'm confused.  Supposedly the 150C wire is rated so high because it needs to carry a lot of current at a lower-than-normal gauge for a certain distance.  At some point, however, it has to attach to wire of some other gauge... so what would the bus bar gain you?  Make the attachment wire of a thicker gauge, allowing it to carry the same current but at 75C.

Dan - Owner
http://www.Hi-TecDesigns.com

RE: Wire termination temperature mismatch

(OP)
Thanks for reply, Dan. A bit more details. Under normal operating conditions, these 150C wires are terminated to the equipment also rated for 150C operations. We need to test a part of this system, so we need a transition to lower temp rated wires.  The question is about temperature rating of the termination point. I do not beleive I can connect at one point (say, stud) the 150C running hot wire, and a larger size (for the same ampacity) 75C rated wire(or wires.

RE: Wire termination temperature mismatch

???  If you're running this to equipment not rated for 150ºC, then the 150ºC rated wires MUST at some point in time drop in temperature.  I would think that a couple of feet of wire outside of the 150ºC environment would be enough to drop down the wire temperature to the desired level.

TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Chinese prisoner wins Nobel Peace Prize

RE: Wire termination temperature mismatch

What IR said... just because the wire is rated for 150C doesn't mean it runs at that temp the entire way.  I mistakenly was under the impression the wire would get up to 150C due to a smaller than typical gauge... now I realize it's the insulation's rating.  At some point outside of the equipment the wire will be subject to more normal temps.

Dan - Owner
http://www.Hi-TecDesigns.com

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