what is cabling?

[imported_bdweller]

I do not understand what the term "cabling" means. Could you elaborate? thanks

[Wgoodrich]

Very often I find a person wiring a home with a bunch of home runs [cables in say the attic all running along with each other]. This is fine as long as they lay loose and have gaps to air cool between cables. Problem is often times someone wants to be neat and use cable ties and bundles these cables in a big trunk line of bundled cables. This creates a tight pack of cables that can not cool and are transferring heat to each other much like a bunch of people on a hot July day in a field bunched together holding hands, boy that person in the center is going to get REAL HOT! Same happens with cables bundled together say in a protective conduit longer than 24" or wire tied together or other methods that bundle these cables together limiting the cooling ability designed to be present for current carrying cables that are heating and cooling as they are used with electric load applied then turned off.

Same condition appears when you pack more than 4 current carrying conductors in a conduit even being single strands.

See Article 310.15.B.2 for a chart showing ampacity deration due to more than 4 current carrying conductors in a raceway or Romex cables bunched together. Remember this deration only comes into affect when this bundling or conduit run or bunching is in lengths of longer than 24". Reason for the exception in this bunching or bundling or conduit for less than 24" is the ability for these packed together conductors to cool out the ends if not packed together longer than 24".

Hope this helps

Wg