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Re: [8023-POEP] List of questions regarding cabling and connector s



Regarding the issue of cable heating, I have a concern about Jo Wallings analysis.  In his supporting document, "walling_2_0905.pdf" the last sentence in the second paragraph states "...under the assumption that all pairs in all cables are energized with the same current."
 
This is a valid assumption for PoE Plus, since it appears very likely that we'll use a 4-pair system.  But Jo's assumption is invalid for 802.3af since only half of the pairs are carrying current.
 
So I think Jo overestimated the heat dissipation in the cables (for 802.3af) by a factor of 2.