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I read the PDF file from the second link that Brian Whatcott referenced (the
first link does not work). That second link is a PDF file that is 149 pages
long. The PDF file I created is 3 pages long.
It seems to me that trying to answer some questions without making the
questioner "read the whole book" is one of the things this list is all
about. It also seems to me that pointing out some of the more important
things, including describing some pitfalls and common errors, then letting
the student do further work as necessary, is a part of what teaching is all
about. If I am worried that a student might sue me someday because I didn't
explain something exactly right, or my explanation was incomplete, or I
somehow misled the student, then I shouldn't convey any factual information
to students. I should just assign reading in the textbook, and give exams
on what they read, and let it go at that. Then the students can sue the
textbook writer and publisher, because the author and publisher probably
have deep pockets.
Upon reading the PDF at the end of Brian's link, I found .I had mentioned
all the salient features that needed addressed, I indeed mentioned NEC which
I hope would imply that one might want to check out NEC or state or local
codes before commencing on work where some sort of building codes would be
expected to apply. Specifically I mentioned the need to ground the
equipment cases; I mentioned the need to ground one side of the AC output of
the inverter (this wire would then become the "neutral wire;" I mentioned
the need to ground one of the DC lines to the inverter if the open-circuit
DC voltage is 50 volts or more; I mentioned that some inverters don't allow
this and therefore might not be acceptable; I mentioned grounding for
lightning protection; I mentioned possible ground-loop problems; I mentioned
fire hazards if grounding is not done properly; I mentioned a fusible link
in the DC circuit; I mentioned the possibility of GFCI for the AC output
from the inverter.
In short there wasn't much in the 149-page document that I didn't mention in
my 3-page document. What I hoped my short version would accomplish is to
make it clear that this is more complicated than what was being discussed
before I entered the discussion, and by pointing this out it would be my
hope that the reader who might engage in this sort of project would delve
into these issues before commencing on the project. I suppose I probably
should have stated such along with some sort of disclaimer that my advice is
not intended to substitute for checking into the wiring codes in effect in
the readers city, county, state, and country.
In a private message, John Denker pointed out some points that would improve
my document in terms of lightning protection, EMI information, and he
thought I might do more explaining of terminology such as "neutral wire" and
color codes for wires, etc. I thank John for his suggestions, but so far I
haven't modified my document to incorporate his suggestions because it
wasn't clear that many list members were interested.
I don't completely thumb my nose at the possibility that someone might find
the info we discuss on this list, and get themselves into trouble, and try
to sue us. I suppose that is a possibility. Yet, if we can't freely
discuss these issues, then we might as well dissolve the list. We probably
ought to quit teaching also. Goodness, one of the things I am required to
include in my teaching of physics and chemistry labs is safety. This is
especially true for students headed into middle-school and high-school
science teaching. If I am substantially at risk because one of my students
might go teach high-school science, and one of his/her students gets
injured, and the law suit makes its way back to me because I either failed
to point out that particular danger, or I didn't completely assure the
prospective teacher had properly learned it... I guess I better get out of
teaching. None of my students graduate with a thorough grasp of everything
they might have grasped in college. Do I need to live in fear that all
those shortcomings of all my students are going to come back to bite me.
Michael D. Edmiston, Ph.D.
Professor of Chemistry and Physics
Bluffton University
1 University Drive
Bluffton, OH 45817
419.358.3270
edmiston@bluffton.edu
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