Your wiring approach is correct and I made no earlier comment or reference
to it. The "group" issue is merely that the spikes which travel among
grouped fixtures and cause this failure only occur when more than one
fixture is wired on the same switched (parallel) circuit. The very same
fixtures installed individually do not fail in the manner I described.
Smarty
"J.A. Michel" wrote in message
...
I learned that lesson as you did many years ago. I bought a cheapo
fixture, and it was terribly noisy and it would not light below 60 degrees.
I will not buy a fluorescent light unless I'm allowed to open a sample and
inspect the ballast. I'm no expert, but the ones with the big, heavy duty
ballasts seen to be the way to go. When the ballast goes bad, time for a
new fixture. It's not the time or expense to replace just the ballast. As
far as my reference to the wiring, Why does it make a difference? Hot to
hot, neutral to neutral, ground to ground. Why does it make a difference
when wiring them in a group? You lost me on that one.
"Smarty" wrote in message
...
You are entirely correct. The fixtures were, as you said, what one might
expect for such a low price. The point of posting this was to illustrate
that all fixtures are NOT created equal and for fluorescent fixtures
specifically, this makes a whole lot of difference when wiring them up in
group as I did.
Smarty
"J.A. Michel" wrote in message
...
"Smarty" wrote in message
...
Just for the record, I have to report that fluorescent fixtures do not
***ALWAYS*** perform the same as incandescents even if they are wired
the same:
I purchased 24 fluorescent strip lights from Home Depot, each
containing an electronic ballast and sockets for 2 fluorescent T-8/T-12
style 32 watt bulbs. These fixtures use the newest electronic ballasts,
are extremely efficient, make no hum or other noises like magnetic
ballasts, and were on sale for $6.99 per fixture.
When they were all installed as three sets of 8 fixtures, each set on
its' own circuit/switch, I found that an extremely high rate of
failures occurred, arising from what I subsequently learned is called
"ballast fratricide", a process wherein the switching transients from
the ballasts all being simultaneously switched results in spikes which
the ballasts are unable to dissipate without damage.
It turns out that strip lights especially are not filtered adequately,
neither in terms of the emitted spikes which damage other
nearby/connected loads, nor in terms of rejecting fast transient spikes
which arise elsewhere and need to be dissipated.
I spent some time with an oscilloscope and a lot of measurements before
being able to find where the problems were, and have subsequently
learned that others have reported the same type of problem with the
newest electronic ballasts in some commercial installations.
If one takes an in-depth look at the schematic and waveforms produced
by the electronic ballast during the start-up cycle, and also looks at
the chipset spec sheets from the ballast ICs involved, it becomes
apparent that huge switching transients are typical, and that external
filtering is up to the fixture designer who incorporates these ICs into
their ballast.
The bottom line is that some fluorescent fixtures cannot be simply
wired as if they are incandescents, since they will destroy their
neighbors and themselves, in my case over only a few days of normal
use.
My solution was ultimately to replace all 24 ballasts with another,
better filtered design which, unlike the Home Deport brand, have a lot
of spike filtering as well as a 5 year warranty.
Here is another example of this type of problem:
http://lighting.copperwire.org/7.2.php
Smarty
@ 6.99 per light, you got *exactly* what you paid for.