[AusNOG] Fwd: Derating of PDU

[Jrandombob]

Alex,

    Not sure if there's any standards around it.

But from an electrical engineering perspective conductor heating (what
you're managing by derating) is a larger issue in 100/110V countries as
I^2R losses are greater. Higher voltage (lower current) means the
resistance of the conductors causes less heating thus you're less likely to
go outside of the conditions for which the conductors (and moreover their
insulation) are rated.

Best Regards,

Morgan

On Tue, Apr 8, 2025 at 4:49 PM Alex Samad <alex at samad.com.au> wrote:

> Hi
>
> I'm having the pleasure of looking at PDU's and trying to standardise over
> US / UK / Japan / Aus
>
> Something I didn't know was the standard in the US for derating electrical
> devices. whilst I normally plan for max normal draw of around 80% of
> rating. seems like PDU for USA have a derating value.
>
> So I am seeing 30amp @ 230v in and line rating of 24amp and max 30amp.
> The notes seems to suggest you can go over 24 amps but only for a very
> short period of time - seems like minutes.
>
> This seems a bit of a pain for me - whilst I wouldn't normally run over
> the 24 amps there have been times i have had to run over - but under 30 for
> days if not a couple of weeks.
>
> Currently I'm trying to order into japan (omg), lot of their stuff is
> imported which means it comes with the USA specs.  so 24/30 amp setup..
> Interestingly also noted that when you read the fine prints its actually 2
> x 20amp breakers - 1 breaker per bank .. PDU has 2 banks
>
> I can't find anything about derating for Aus - do we not do it in Aus or
> mandate it ?
>
>
> Alex
> _______________________________________________
> AusNOG mailing list
> AusNOG at lists.ausnog.net
> https://lists.ausnog.net/mailman/listinfo/ausnog
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.ausnog.net/pipermail/ausnog/attachments/20250408/809341ec/attachment.htm>