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Path: utzoo!utgpu!water!watmath!watcgl!onfcanim!dave
From: dave@onfcanim.UUCP
Newsgroups: sci.electronics
Subject: Re: electrical cord marking/rating
Message-ID: <15371@onfcanim.UUCP>
Date: Thu, 20-Aug-87 11:25:55 EDT
Article-I.D.: onfcanim.15371
Posted: Thu Aug 20 11:25:55 1987
Date-Received: Sat, 22-Aug-87 09:42:20 EDT
References: <1697@sfsup.UUCP> <983@cooper.UUCP>
Reply-To: dave@onfcanim.UUCP (Dave Martindale)
Organization: National Film Board / Office national du film, Montreal
Lines: 35

In article <983@cooper.UUCP> gene@cooper.UUCP (Gene from EK Enterprises) writes:
>
>> What is "SJT" ??
>
>Well, if memory serves me correctly (no parity errors, etc.), the SJT
>refers to the plug type: two flat conductors with the semi-rounded ground
>connector. Air conditioner plugs are different, for example; they have the
>thicker prongs, with the two flat conductors being colinear instead of
>parallel ( -.- as opposed to '.'). Oh, well...

No, "SJT" refers to the wire itself.  The "S" means "rough Service" -
any time I've ever seen this designation, the wire was round, with an
outer insulating jacket around the three conductors (also individually
insulated).  There is also filler material in the space between the
conductor and jacket, adding strength and crush resistance.  Basically,
the wire is intended to withstand some abuse, such as it would receive
in an extension cord.

The "J" means "Junior" - a smaller version of the cable, that would stand
up to less abuse.  Compared to an "S" cable, an "SJ" cable may have
only half the insulation thickness, and is probably a lot cheaper - that's
why you don't see "S" cable very often.

Finally, the insulation jacket material is rubber by default.  A suffix
of "T" means that it is plastic ("Thermoplastic") instead.  There are
other suffixes too; the only one I can remember at the moment is "O"
for "Oil resistant".

All of these refer to the wire itself, whether it has anything installed
on the ends or not.

As for plugs, there are a variety of standard configurations for various
voltage and current ratings.  We all know what 120V 15A plugs look like
in North America.  The ones with the flat blades both rotated 90 degrees
are for 250V 15A service.