Re: [8023-POEP] 802.3af Isolation 33.4.1
Hi Bob,
While I cannot give you an official answer, as a personal observation I
would state that as far as I am aware there have been no changes to
subclause 33.4.1 since the approval of IEEE Std 802.3af-2003.
If you are interested in the background to the development of this
subclause you may want to review the IEEE P802.3af DTE Power via MDI Task
Force web archive [ http://www.ieee802.org/3/af/index.html]. As another
personal observations, I do seem to recall that there was a lot of work on
this subclause during the devolvement of draft D4.1 in particular. I would
therefore suggest looking at the comment and responses database for D4.0 [
http://www.ieee802.org/3/af/comments/d4.0/P802_3af_D4_0_all_final.pdf ]
and searching the file for '33.4.1'.
And finally, before the Chair of this Study Group has to remind us all, to
quote the reflector welcome message 'The IEEE 802.3 Power over Ethernet
plus e-mail reflector is provided to the members of the IEEE 802.3 Power
over Ethernet plus Study Group for the benefit of moving the work of the
Study Group forward.' I will therefore note that this question relates not
to the IEEE Power over Ethernet plus Study Group, but instead to the
approved standard IEEE Std 802.3af-2003 DTE Power via MDI.
Best regards,
David Law
> From: Lappin, Bob <rlappin@xxxxxxxxxxxxxxxxxxx>
> Date: Apr 20, 2005 7:59 PM
> Subject: [8023-POEP] 802.3af Isolation 33.4.1
> To: STDS-802-3-POEP@xxxxxxxxxxxxxxxxx
>
> I would like to know the reasoning for the change to the Isolation
> requirements in paragraph 33.4.1.
> Previously, 2250VDC was an acceptable test option. That option is no
> longer shown in the 802.3af specification.
> The MDI interface will typically have a capacitive path to frame
> ground to attenuate common mode noise. This capacitance will conduct
> AC current up to as much as 30mA during the electrical strength test.
> Could someone please explain the reasoning for not allowing the
> 2250VDC electrical strength test?
> Thanks
> Bob Lappin
> Tyco Electronics