Parallel Reality Danger? [RE-wrenches]

Sun May 26 10:19:51 PDT 2002

I propose that Ray's conundrum be added to new CA. C-46 licensing exam
with an additional question as well: if a moose chews through an array
wire in the forest, is shocked and faints dead away and there is no one
there to hear the commotion or to see the moose fall, did it really
happen?  Contemplate the sound of one hand clapping....

marco
proVision technologies, inc.
hilo, hawai'i
www.provisiontechnologies.com

	Hi Bill and all;

	Here is another potentially dangerous situation to ponder: a
5amp UL listed
	device (a computer) is powered through 16 awg SJO cord to a 15
amp rated
	receptacle. This receptacle is PARALLELED with several other 15
amp rated
	receptacles (35cents made in China). This whole circuit is fed
through a 20
	amp breaker. Coffee spills on the computer creating a short.
Because of the
	time/ current performance of the breaker, over a hundred amps
could pour
	into our soaked device for a few seconds and  20 amps could flow
	continuously into a device UL listed for only 5.
	Compare this scenario, with my maligned array wiring method: two
array
	strings each having a short circuit output of 4.75 amps and a
series fuse
	rating of 15 amps feed thru 12 awg wire  in parallel for a total
of 9.5
	amps to a 15 amp breaker. A moose chews through the wire
creating a short.
	Up to 15 amps continuous are allowed to backfeed into the
circuit ( the
	charge controller also failed) and are boosted another 4.75 amps
by the
	paralleled string. This time almost 20 amps could possibly (but
not
	probably because of the high resistance) flow into a device UL
listed for
	only 15.
	Why is the first condition allowed, but the second is not? Is
120 vac safer
	than 48 vdc?

	Sincerely again,

	Ray

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Experience counts. Last year Japanese wrenches installed 110 MW of grid-tied PV
including 20,000 approx. 3 kW residential installations. German wrenches
installed 75 MW of grid-tied PV. In just one year they did more than the total
U.S. installed inspected PV systems. Aside from language differences, is there
any reason why there are no German and Japanese wrenches on this list? What can
we do to recruit input from Japanese and German wrenches?

Dana Orzel wrote:

> The dilemma of non wrenches and non wrench salesmen is based on lack of
> installation and material selection experience. Experience teaches lessons.

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