Low Voltage lighting vs A.C.

[David B.]

I want to do some landscape lighting and wondering if using a 12volt
system(20 watt bulb) is more efficient than normal 120 volt (20 watt Bulb).

 

[Phil Allison]

"David B."

I want to do some landscape lighting and wondering if using a 12volt
system(20 watt bulb) is more efficient than normal 120 volt (20 watt
Bulb).

** In a word - no.

But you may well find that only 12 volt is legally allowed on safety
grounds.




....... Phil

 

[David B.]

Thanks Phil, Is there any advantage in using low voltage recessed ceiling
lighting? Seeing that the fixtures are costlier than line voltage cans, why
are they becoming so popular?
Dave

 

[Phil Allison]

"David B."

Thanks Phil, Is there any advantage in using low voltage recessed ceiling
lighting? Seeing that the fixtures are costlier than line voltage cans,
why
are they becoming so popular?

** Its all about the looks.

Spot lighting, pretty effects, full range dimming etc, et alia.




...... Phil

 

[Eeyore]

I want to do some landscape lighting and wondering if using a 12volt
system(20 watt bulb) is more efficient than normal 120 volt (20 watt Bulb).

Low voltage halogen bulbs are more efficient than 120/230 volt tungsten
incandescents.

Was that what you wanted to know ?

Don't forget about the serious effect of volt drop due to cable resistance with
low voltage lighting though.

Graham

 

[Rich Grise]

I want to do some landscape lighting and wondering if using a 12volt
system(20 watt bulb) is more efficient than normal 120 volt (20 watt
Bulb).

If you use fat enough wire, the efficiency should be practically the same -
the thing is, 12V doesn't kill pets or children.

Cheers!
Rich

 

[David B.]

I wanted to know if I would save on the electrtic bill by using 12volt. Will
be doing lanscape and soffit lighting. I have 18 ga safty wire that I can
use to minimize the voltage drop.
Dave

 

[Bob Myers]

I wanted to know if I would save on the electrtic bill by using 12volt.
Will
be doing lanscape and soffit lighting. I have 18 ga safty wire that I can
use to minimize the voltage drop.

You won't save a significant amount, no. In fact, it is at
least possible you'd wind up spending a miniscule amount more.

Bob M.

 

[Charles]

If you use fat enough wire, the efficiency should be practically the
same -
the thing is, 12V doesn't kill pets or children.

I agree with Rich ... 12 volts is a lot safer than 120 volts. Also, it
eliminates the need for conduit and expensive direct burial cable and that
kind of stuff.

Efficiency, general speaking, is poorer with low-voltage systems. Not a big
issue unless you are going to have a rather extensive outdoor lighting
system.

 

[Ken Fowler]

I wanted to know if I would save on the electrtic bill by using 12volt. Will
be doing lanscape and soffit lighting. I have 18 ga safty wire that I can
use to minimize the voltage drop.
Dave

Your 20 Watt lamp will draw ~1.6 amps from 12 Volts. 18 gauge wire might be enough for one or two
lamps but will not minimize the voltage drop. The system is not very efficient if power is lost in
the wires. 14 gauge would be better.

Ken Fowler

 

[Eeyore]

I have 18 ga safty wire that I can use to minimize the voltage drop.

LOL ! Forget 12V then !

Only the other day I was looking at ~ 4mm^2 cable feeding 50W halogen fittings.

Graham

 

[Eeyore]

"David B."

** Its all about the looks.

Spot lighting, pretty effects, full range dimming etc, et alia.

Also those fittings have little depth so can be flush fitted. You couldn't
easily do that otherwise.

So, what are ppl going to have in their kitchens (the most popular place in the
UK for low voltage halogens) when incandescents are banned then ?

Back to those exposed tube florries ?

Graham

 

[David B.]

Hi Ken my mistake the wire is actually 12 ga. its not regular romax . Its
the type used for emergency lighting and fire systems.
Dave

 

[Phil Allison]

"David B."

I wanted to know if I would save on the electrtic bill by using 12volt.
Will
be doing lanscape and soffit lighting.

** Then use compact fluoros - that is something they might be good at.

You can get them now in ratings of 7 watts, or maybe less in " mini
spiral" types with " warm white " colour.




....... Phil

 

[Jasen]

Thanks Phil, Is there any advantage in using low voltage recessed ceiling
lighting? Seeing that the fixtures are costlier than line voltage cans, why
are they becoming so popular?

low voltage halogen downlights last longer than mains voltage halogens
and give better colour etc...


Bye.
Jasen

 

[John Larkin]

low voltage halogen downlights last longer than mains voltage halogens
and give better colour etc...

For the same reason 120 volt bulbs last longer than 240's: a short fat
filament takes longer to evaporate.

John

 

[Phil Allison]

"Jasen the ASD fucked kiwi MORON "

low voltage halogen downlights last longer than mains voltage halogens

** Not the comparison that was asked about.

and give better colour etc...

** BOLLOCKS.



........ Phil

 

[Ross Herbert]

I want to do some landscape lighting and wondering if using a 12volt
system(20 watt bulb) is more efficient than normal 120 volt (20 watt Bulb).

It is much safer to use 12V for domestic outdoor lighting. Depending
on the number of lights you wish to drive you may use either
individual transformers for each lamp or a larger common transformer
for a group of lamps. Because of the importance of maintaining low
volt drop in the 12V cabling you will need to mount the supply
transformer as close as possible to the individual lamp, or in the
case of a common transformer, as close as possible to the centre of
each group of lamps.

In order to get the transformer as close to the lamps as possible it
is usual to mount them on an outside wall or a verandah/porch support
post, or in some cases, in an underground pit. This makes it mandatory
for the transformers to be weatherproof where rain or water is likely
to be encountered, or fully encapsulated for underground use.
Individual lamps can be powered from a plug pack transformer designed
for soft starting low voltage lamps eg Tridonic Atco ACT35-2 (see
p.209 document below). Grouped lamps can be powered using the
weatherproof LVL 6 or 10 series transformers (p.211) or the fully
encapsulated LVL48A series (p.212) for underground applications. There
should be similar versions for 120Vac applications from US
manufacturers.

If using a common transformer, then depending upon the wattage of each
lamp, and the cable gauge & length, you may be able to connect more
than one lamp on a 12V cable run. On longer runs it may be better to
power 1 lamp per cable run. This will need to be determined by what
circumstances and materials apply to your particular situation.

This document
http://www.tridonicatco.com.au/MEDIEN/CAT0304_AU/TRANS.PDF while
applying to Australia where 240Vac mains is the norm, contains
information which is pertinent to low voltage electromagnetic lighting
transfomers used anywhere, particularly with regard to the requirement
for good regulation with variable load to increase lamp life.

 

[Eeyore]

It is much safer to use 12V for domestic outdoor lighting.

Just a thought.

Why not 24V ?

Graham

 

[Jasen]

** Not the comparison that was asked about.

not the message I was respondinfg to.