[Elecraft] Breakers for KPA1500?

[James F. Boehner MD]

WOW!

Thanks for that link!  Now just to find it in PDF.

'73 de JIM N2ZZ


-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Mark Goldberg
Sent: Monday, July 09, 2018 8:27 PM
To: hawley, charles j jr
Cc: elecraft at mailman.qth.net
Subject: Re: [Elecraft] Breakers for KPA1500?

Actually, if you look at the NEC (National Electrical Code), they have
factors for ambient temp and wire temp ratings. Other codes around the
world are similar.

For example, if you use AWG 12 Type UF cable, the base rating is 20 Amps.
With the temperatures we have in Arizona, where it can get above 140F in an
attic, they have a correction factor of 0.71 if the wire is rated to 90C.
So it should only be used up to 14.2 Amps. If you are installing from
scratch, I would go to AWG 10 just for a safety factor. Of course, you may
not be here in Arizona. It actually may get hotter than that here in some
attics.

You can read the NEC for free by going here and signing up. It will tell
you more than you want to know, in excruciating detail. A copy will cost
ya, but I have found the online interface good enough to find things.

https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-cod
es-and-standards/detail?code=70

73,

Mark
W7MLG


On Mon, Jul 9, 2018 at 4:49 PM, hawley, charles j jr <c-hawley at illinois.edu>
wrote:

> How many watts of heat does the average attic have in the summertime?
>
> Chuck
> KE9UW
>
> Sent from my iPhone, cjack
>
> > On Jul 9, 2018, at 6:39 PM, Josh Fiden <josh at voodoolab.com> wrote:
> >
> > If wire run ends up being 50' you could see a 2V drop at 13A. Agree that
> switching supply in amp won't care. 26W of heat in the wire inside a wall
> would bug me.
> >
> > 73
> > Josh W6XU
> >
> > Sent from my mobile device
> >
> >> On Jul 9, 2018, at 3:12 PM, Roy Koeppe <k6xk at ncn.net> wrote:
> >>
> >> The KPA1500 uses a regulated power supply: input 195 to 250 vac.
> Voltage loss in #12  wires is so small the regulator will laugh at that.
> >>
> >> 73,   Roy   K6XK
> >>
> >>
> >> "I would also suggest using three -  #10 with ground as the line from
> the
> >> breakers to the amp operating position."
> >>
> >> 73
> >>
> >> Bob, K4TAX
> >>
> >>
> >>> On 7/9/2018 11:43 AM, Roy Koeppe wrote:
> >>> Yes, that is what I am using.
> >>>
> >>> 73,   Roy     K6XK
> >>>
> >>>
> >>> I probably missed this but my google searches aren't working either.
> >>>
> >>> Will 2x 20A breakers (220v) be sufficient for the KPA1500?
> >>>
> >>>
> >>
> >>
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