On Tuesday, December 22, 2015 at 12:08:38 AM UTC-6, wrote:
On Mon, 21 Dec 2015 22:19:05 -0600, Mark Lloyd wrote:
I use 2 or 3 (one for inside plants in the winter) such timers, and have
a list of the mean sunrise and sunset times for each of the 14 months.
BTW, I suppose you know why it's 14 months rather than 12.
You lost me on this 14 month thing?
Timers work fine, but you need to keep resetting their time to match the
seasons. That's kind of a hassle. Photocells are much easier to use.
Back when I was working as an electrician, I had to add a separate
200amp panel for a guy who ran a huge xmas yard display every year
during the season. His house had a 100A panel and could not handle this
xmas display, so we just installed an extra panel, with all sorts of
outdoor outlets, which was pretty much dedicated to his xmas setup.
His display which was running at least 70 amps continuous. (this was
before LED lights).
He asked me if it was possible to install a timer to shut off the entire
display at once. I looked at some electrical catalogs and could not find
anything at that amperage, not to mention it would need to be connected
to the MAINS, and that would have gotten into all sorts of code things
that we were not prepared to deal with.
I explained to him that he was using at least 8 circuits, and would have
to put a separate timer on each circuit. However, I began to think about
using relays, and having one timer flip on and off eight 20A relays.
This would have worked, but building it and having all the cords to go
to each circuit would have been costly. He decided to just go with the 8
timers, and try to program all of them to turn on and off at the same
time. He had a beautiful display, but I'm glad I did not have to pay his
electric bill.
A shunt trip main breaker with a low voltage control circuit on a timer. Or several shunt trip breakers. I used to install them in restaurants to kill the power to electrical cooking equipment under the hood when the fire suppression system was tripped. (€¢€¿€¢)
http://www.answers.com/Q/What_is_a_shunt_trip_breaker
[8~{} Uncle Trippy Monster