🚀 go-pugleaf

Not sure what country you're in, but you will NEVER pass a local code
inspector in the US (if in an area that requires inspection) with home made
fixtures.

Another issue to consider.  The greatest concern you face with 12v systems
is voltage drop.  If you have LONG runs, this will become a significant
problem.  DO NOT use small cable... #12 is the preferred roadway if running
under 75ft (IMO)...  and another issue to consider is amperage.  Remember
that #12 cable is good for 20 amps.  I'm sure you're very aware of the
formula to figure your max allowable... and I'd urge you to consider no more
than 300 watts on ANY circuit.  DO NOT pump up the transformer in order to
put more fixtures on that circuit.

In fact, most major manufacturers in the US rate all transformers at
300Watts or less.  And in 12V landscape lighting, UL will not permit any
circuit above 300 Watts.

Hope that helps, and feel welcome to drop me a line for more info.

Wes


"DaveC" <anon@bugus.net> wrote in message
news:0001HW.BA977EAD001869E90E6B7920@news.covad.net...
> I've been asked to help light a small office building hallway. The
> fluorescent lamps are way too harsh for the office workers, and the
tenants
> favor the overhead QH approach.
>
> I've looked at the local home centers' lighting departments and see quite
a
> selection of LV systems using overhead steel cable with 3 hanging
reflector
> bulbs (with a choice of trim, or not) tapped in at appropriate intervals.
>
> Price for the above from $70-100us.
>
> Being encouraged by what I saw, I decided to see what I could build from
> scratch.
>
> As you probably can guess, I'm running into current supply/demand
> limitations. Each of the 2 hallways could use about 15 lamps. Lamps are
> available in 20 and 50w versions, which at 12v, draw approximately 1.7a
and
> 4.2a, respectively. I now see why the cost of such a system is mostly for
the
> supply.
>
> Looking for a ready-made 12v supply, I find this at Jameco for $70us that
> provides 12.5a:
>
> <http://www.jameco.com/cgi-
>
bin/ncommerce3/ExecMacro/Jameco/searchResult.d2w/report?sort=BPA&search=1234
22
> >
>
> This would allow me to run 7 of the 20w lamps, or only 2 of the 50w lamps.
>
> I can't see buying 2 supplies to run the 15 (well, I guess we could rev
that
> to 14) lamps in each hall. I seem to be butting up against Ohm's Law.
>
> Maybe build a simple, unreg'd, analog power supply with massive
transformer
> and rectifiers for 30A?
>
> Any other ideas (or links to sites) to help me reach a solution would be
> greatly appreciated.
>
> Thanks,
> --
> Dave C
> dave+usenet3016@mailblocks.net
>
>