[simpits-tech] RE: CP Clock

[Rochester, Craig]

I have seen two fires from electrical wiring.  Both were wired per US
electrical codes(wire size vs. loads).  Both  started at screw connector
terminations housed in plastic junctions boxes.   Chemical cleaning
solutions had infiltrated the junction boxes' gaskets and caused corrosion
of screw/wire connection.  No design can counteract poor workmanship, abuse,
and lack of proper maintenance.

We were lucky that the fires occurred when people were around and were
quickly extinguished. There was minimal damage and no injuries.  I use metal
electrical enclosures whenever possible.  

		-----Original Message-----
		From:	Ben Jones [mailto:bjones@pipecomp.com.au]
		Sent:	Friday, October 25, 2002 6:33 AM
		To:	simpits-tech@simpits.org
		Subject:	RE: [simpits-tech] RE: CP Clock

		Really where the fuse is in the circuit between the supply
and the load is not a real worry, 
		if the fuse is only protecting the cable that it is
connected into , the physical placement at the supply end middle or the load
end of the cable , is  irrevelant  only if the fuse is correctly rated for
the wire current carrying capacity, 

		eg if the cable is capable of carring 10 amps a safe thing
to do is set the fuse size to about 8 amps for safety sake , but when cable
is produce it has saftey margins built in so a cable that is labelled 10
amps max , you can assume that for short to medium time periods you could
pull about 14 amps , SHORT TIME ONLY !!
		if you have a load which pulls 7 amps through a 10a cable it
is safe to set the fuse for 10a trip/blow, because if the safety margin in
the cable.

		never rely on the safety margin of tha cable as this is when
you get in to the area where the (usally ) pvc sofens then melts and the
bang shorts,to either earth of a close cable .

		i was witness to this ona industrial site where the cable
was max rated to 400 amps at 5KV the techo/operators increased the load
slowly to fool the circuit protection ended up pulling 480 amps through the
cable for 5 hours, they did this multiple times throughout the day the ka
boom it went up and vapourised a remote water pumping station to the ground
..Luckly the station was remote and un manned.



		BEN   JONES 
		-----------------------------------------
		bjones@pipecomp.com.au
		------------------------------------------------


		-----Original Message-----
		From: Marv De Beque [mailto:mdebeque@woh.rr.com]
		Subject: Re: [simpits-tech] RE: CP Clock

		>Put the fuse as close to voltage source as you can.
		-- 

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