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Topic Title: Cable Derating Factors
Topic Summary: Cable derating factor for cable installed in basket.
Created On: 21 December 2012 12:37 PM
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 21 December 2012 12:37 PM
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TeesdaleSpark

Posts: 660
Joined: 12 November 2004

What derating factor is appropriate for multilayered cables installed in cable basket.

The cable is from table 4D2A therefore Table 4C1 factors apply in which there are four items. I'm assuming item 1 is more appropriate but others are arguing that item 3 is.

How does Amtech or Hevacomp calculate this?
 21 December 2012 01:21 PM
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OMS

Posts: 19614
Joined: 23 March 2004

For a cable basket, Table 4C1 Item 4 is the closest. Basket presents far more free area than tray (Item 3) and significantly more than clipped direct

It's the lack of cable spacing (and multilayering) that will dominate anyway.

A quick check on Amtech suggests to me (by comparison with Table 4C1) that Item 4 is what they use - although they will vary depending on the layering (bunching) which may push you towards Item 1.

All the assumptions/caveats about equal loading of similar conductor sizes apply.

If it's a problem, put bigger containment in and get some seperation (min 1 x OD and ideally 2 x OD)

regards

OMS

-------------------------
Failure is always an option
 21 December 2012 01:24 PM
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marclambert

Posts: 309
Joined: 23 June 2010

Looking at the table 4C1 item 1 would be good I'd say. Basket is pretty much " bunched in air" isn't it?
Item 3 refers to single layer only.
regards
Marc
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