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Date: Fri, 18 Nov 2011 14:26:45 -0500
Message-Id: <201111181926.pAIJQjXp013321@envy.delorie.com>
From: DJ Delorie <dj AT delorie DOT com>
To: geda-user AT delorie DOT com
In-reply-to:
	<CALSZ9go8y8D1Sv1qg8zL=dQOx_szaWPZ4P3KAXUJ-Wb879gwUA AT mail DOT gmail DOT com>
	(message from Rob Butts on Fri, 18 Nov 2011 14:16:49 -0500)
Subject: Re: [geda-user] Stranded and solid wire data
References: <CALSZ9go8y8D1Sv1qg8zL=dQOx_szaWPZ4P3KAXUJ-Wb879gwUA AT mail DOT gmail DOT com>
Reply-To: geda-user AT delorie DOT com


> This is a basic question but I have searched google to see if there
> is a table for stranded and solid wire ampacity and conductor
> diameter data with varying results.  Is there a good source for this
> or is it manufacturer specific?

Ampacity is determined not by the conductors, but by the insulation -
the higher the breakdown temperature of the insulation, the more
current the wire can handle.  Most online tables show "temperature
rise vs amps per circular mil" - it's up to you to decide how hot you
can afford.

Home wiring insulation comes with a variety of different ratings/types
stamped on it that indicate various characteristics.  My heat pumps,
for example, require THHN insulation for high heat tolerance.

As an aside, for high frequency signals (like switching power
supplies) you'll also see tables of "max frequency for 100% depth" -
skin effect limits, in effect.  For a given frequency, there's a
maximum wire size before you start losing effective cross section area
due to skin effects, which affects your amps/area.