From: "Michael A. Terrell"
Subject: Re: PA (Public Address) Systems
Date: Sun, 08 Dec 2002 16:07:45 -0500
Organization: Have you seen my bench? No, really! Where is it?
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References: <3DF22855.14115CC2@mfi.net> <3DF249B6.937B12BD@mfi.net> <6FYL3ZAH6n89Ewb7@jmwa.demon.co.uk> <3DF2D9B8.6C73AE5A@mfi.net>
ntl user wrote:
> "Michael A. Terrell" wrote in message
> > John Woodgate wrote:
> > >
> > The National Electrical Code classes 25 volt systems as low voltage,
> > and some places are required to use them. Both 70 and 100 volt are used
> > elsewhere, with 70 volt being the most used of all three types. It is
> > simple, if you're used to it. :)
> > --
> In the UK 400V 3-phase distribution (or old 415V that everybody uses) is
> classed as low voltage.
> Less than 50V is something like Safe-Extra-Low-Voltage SELV, which would be
> good for putting speakers in your bathroom!
Low voltage systems don't require conduit, but higher ones may,
depending on the local codes that can be stricter than the National
Electrical Code. In the US, the voltage fed to a home or small business
is called "Secondary", and is 240 V center tap grounded for two 120 volt
feeds, or 240 volts. You can also get 208 three phase, 480 three
phase. "Primary" voltages between the transformer near the house to the
local substation is 2200 to 7200 volts in most places, depending on the
age of the system. Substation to power plant is much higher.
Michael A. Terrell