Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 11 replies
  • Subscribers 39 subscribers
  • Views 1674 views
  • Users 0 members are here
Options
You may also be interested in
This discussion is locked.
You cannot post a reply to this discussion. If you have a question start a new discussion

Cable Current Carrying Capacity

JD

A very basic question

Current carrying capacity of a cable. My understanding is that if I have a cable rated to 6amps this cable will always only ever be able to take 6amps.

I have been suggested that this rating is only true at 230v and that if I was to drop the voltage the current capacity of the cable may increase. My understanding is this is not related, and even at 12v the cable would still only be rated to 6amps?

Thank you for your help!

Parents
  • 0

    Voltages do not affect the copper thickness of the cable - the current warming it up is the failure mode.  Actually although folk like simple things like  '5 amp cable' there is no such thing - the same cable will take many times the rated amps for a few seconds,  and on the other hand needs to be de-rated if it is used in a place where it is already hot, or the heat cannot get out because it is in the middle of a bundle of other cables, or under the carpet, or something.

    The only time voltage comes into it is in terms of the insulation, usually plastic, that separates the wire - high voltage cables need thicker plastic.

    But thicker insulation acts as thermal lagging, so  the car version of the same cable, with a thinner plastic jacket, may be OK running at a higher current than its mains equivalent that is insulated and sheathed.
    Mike.

Reply
  • 0

    Voltages do not affect the copper thickness of the cable - the current warming it up is the failure mode.  Actually although folk like simple things like  '5 amp cable' there is no such thing - the same cable will take many times the rated amps for a few seconds,  and on the other hand needs to be de-rated if it is used in a place where it is already hot, or the heat cannot get out because it is in the middle of a bundle of other cables, or under the carpet, or something.

    The only time voltage comes into it is in terms of the insulation, usually plastic, that separates the wire - high voltage cables need thicker plastic.

    But thicker insulation acts as thermal lagging, so  the car version of the same cable, with a thinner plastic jacket, may be OK running at a higher current than its mains equivalent that is insulated and sheathed.
    Mike.

Children
No Data

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.

Join us Not now

Community Rules & Guidelines