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Misc. Install Stuff

Hi Guys... Gals?,

 I agree with John on the old style " 66 " sign designs.  My favorite is the
ones they make from stainless sheet.  With the highly corrosive atmosphere in
Atlantic City,  those signs are still the best looking after 40 or so years.  I
am looking to collect a few when the business finally go.  For years I used
glass sleeving as the only way to go.  Now I use non-metallic greenfield.  I am
of the opinion that ground and neon secondaries have no place together. I
guess you could say that I am the other side of the fence on this one.  But I
stand firmly behind all of my installs ( many of which were retrofits of
metallic jobs that were very problematic and hazardous ) with the
non-metallics. Most of the repair work I do is caused by failure modes where
the high voltage was seeking ground ( as it is designed to do ).  My philosophy
is that the voltage will take the path of least resistance to ground and I
would prefer that path to be through the tubes.  Why give it a choice?  The
ground philosophy comes from the notion that a short to ground will trip a
breaker somewhere or other protection device.  With transformer secondaries
that doesn't happen.  The other notion is that if you have metal you won't
have fire.  The theory is that the metallic conduit or greenfield will "sink"
the voltage to earth and eliminate a potential difference to surroundings.  I
find this to be incorrect in practice. The high voltage, high frequency
corona's tendency to migrate at the surface of a conductor rather than the
interior and the rapid voltage swing and capacitive effect of the "shield" does
not NOT sink the voltage but rather builds a potential on the ground plane.  I
have seen many a job where the electricians kept adding more and more ground
wires in an attempt to provide sufficient pathways for this voltage to bleed
off without success.  The ONLY argument I agree with against plastic greenfield
is UL's desire for less plastic  in plenum spaces, etc. because of the toxic
combustion by-products.  But the source of the fire would not be the
transformer secondary GTO !

 Note that a lot of this can be eliminated by underloading the transformer as
Ted mentioned as his preference.  This is also why his installs with grounded
metallic secondaries work.  He does not produce the high voltage / high
frequency that results from an overloaded transformer.  One interesting  point
is that transformer manufacturers recommend that you load on the heavy side
rather than the light side which is how I do it also.  I usually take the
transformer chart and go up one transformer than is recommended.  I might have
lost 2 transformers in 20 years.  I think one of them was due to a lightning
surge.  The other was due to a very small tube ( before I knew that you had to
add extra fill pressure to baby tubes) that failed and took it out.  When the
truck delivers glass to my shop I always wonder why it is filled with
transformers being returned for warranty replacement.  I can't figure out why
the other sign guys burn them up.  Maybe it is the metallic conduit and
improper loading???

 As for Paul Davis,  you are right that he is doing a good job at bringing all
of this into the open and I agree with many, many of his points on the state
of installation today.  But I will be at that seminar by Paul Davis at Sign
Wold '95 ( Eastern States Sign Council )  in Atlantic City.  The seminar is
Nuts and Bolts of Safe Neon Installation.  I plan to talk on a lot of
subjects.  I feel that UL and the NEC are strapping the legit shops ( who don't
take on gray area jobs due to litigation fears ) and those jobs default to the
fly by nighters who don't worry about such things.  The result is that more
work is done by less experienced installers doing what they have to do to get
the job done cheap.  Can you say " FIRE "?  Then what happens?  More rules,
etc. That is why I do wholesale work.  While I do what I consider bullet proof
installs,  I don't do them by UL 48 or NEC exactly.  And I do less and less of
them.   I always have a licensed electrical guy put in the AC so he can be the
fall guy.  Like he knows the sign code! ( no, the lawyer does )  But I refuse
to use metallics.  I couldn't sleep at night.  JMHO !@  BTW,  the local
inspector has NEVER bothered me about my installs.  He calls me for advice.  I
told him to go to the last sign convention and talk to the manufacturers and he
took the time and interest to do just that.

 While on the subject.  I think that secondary protection circuitry is going to
be the wave of the future.  Once it is workable,  it will go a long way to
protecting jobs that some Bozo put in.  The idea of reducing the secondary
voltage of transformers to 10k max will only cause more problems.  As it is
now,  you have guys overloading 15k transformers.  If you give them a 10K,  do
you think that they won't overload them too? And there will be more
connections to fail with more transformers, etc.  Just another area I don't
agree with.  Funny how most of the solid state transformers aren't above 10K.
I wonder...  Maybe I'm getting to be one of the "old guys" but that is what
John made this mailing list for.  Looking forward to the commentary.

  E-mail from: Tom Biebel, 09-Sep-1995