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View Full Version : Converting line voltage lighting system to LED low voltage?


Braphael
04-25-2010, 10:01 AM
I am being asked to redesign the landscape lighting system for an outlet mall. The existing system uses line voltage uplighting in all of the planting beds. The fixtures are currently placed in the outer corners of the beds where people trip over them and break them. The beds are scattered throughout the concrete walkways of the property. The insurance company wants them redesigned to be safer. I'm thinking this would be a great opportunity to convert to a low voltage LED system and be able to use the existing wiring. I have asked for the schematics of the lighting circuits to see what I'm looking at. I plan on using CAST bullets and pathlights with LED bulbs from James. Any suggestions would be appreciated. Thanks!

steveparrott
04-25-2010, 02:24 PM
Hi Bill,

Great opportunity. A few suggestions:

1. An obvious one - relocate the fixtures so people don't trip on them. If needed, you might want to propose edging stones to keep people out of the garden beds!

2. Don't use the existing wiring - especially if the insurance company is on your back. The old wires are unlikely to be rated for lv, so you're risking an NEC violation. Also, from a practical standpoint, the old wires will be corroded and will make poor connections. Also quite likely, the existing wiring configuration is equivalent to a daisy chain - you'll want to use Spider Splices to ensure equal voltage at each fixture - even with low wattage LED's, the distances involved in a mall will stretch the acceptable voltage range. It's good that you're getting the wiring diagrams, hopefully all the existing wires are in conduit under the concrete so you can use them as pull wires to get your new wires through.

3. Make sure your path lights are firmly seated. Backfill around stakes with tightly packed pea gravel.

4. Use pvc conduit for wiring through garden beds and edges, and bury extra wire far beneath mulch areas.

5. Don't forget to use the Fixture Record Tags to record wire run number and transformer number. James' LED's won't appear on the tag, so be sure to record re-lamping info back at the transformer.

6. Take charge of the lighting design and be sure to include specific lighting goals, principles, and techniques to justify your proposal. Your goals are not just safety and security - play up the goals of customer experience and the potential to elevate the overall visual appeal and value of the property.

Braphael
04-25-2010, 02:52 PM
Hi Steve,
Thanks for the quick response. I'm clear on everything except the LV rating. Are you talking voltage rating or current carrying capacity? Why can't a wire rated at 300v or 600v be suited for 12-15v? Current carrying capacity and daisychaining is another story, which I understand.

David Gretzmier
04-25-2010, 03:57 PM
I am guessing there is already a tork type timer or two, or they may have done a two or three pole timer to wire 2 or 3 ciruits for the eisting line voltage stuff. converting to LV will requite a small trans hooked up to that line voltage at every island that is powered from that same timer, thus engaging all trans at once. all wire from trans to fixtures should be new. You can't beat Cast bullets for toughness in a commercial area.

I would at least be honest with the customer about the LED bulbs and how long they have been out there and the real world outdoor experience with them. Give them a choice of halogen or LED and tell them the pro's and con's of each. You will still need to come back and maintain the lenses, cut back plant material, re-aim and I would still pull the LED bulb and regrease the mr-16 socket and o-ring each year, then re-install bulb. I have seen too many stainless steel pins rot off in sockets after 3 years to just ignore that bulb year after year. I may be way off base on the need to do that, but it can't hurt.

Braphael
04-25-2010, 04:06 PM
Thanks David! I will know much more when I see the wiring diagrams. I do plan on offering a semi-annual maintenance schedule. I agree that your idea of using a small transformer in each bed is probably the easiest way to convert to lv. That may be the way I propose the design.

INTEGRA Bespoke Lighting
04-25-2010, 04:49 PM
Good advice all around.

You might want to consider using a below-grade transformer in those garden beds to keep things hidden. You could also get away with a small ACME style transformer (hardwired) as the load per bed will be quite low.

What are the ambient light conditions at this site? Is there a lot of overhead parking lot lighting, sign lighting, and other sources of bright light? I ask because the LED lamps currently available are 20W halogen replacements. I don't want to sell myself out of a position... but you need to think of ambient light conditions when planning this new lighting system.

Braphael
04-26-2010, 08:48 AM
The ambient light conditions are different throughout the property. There are 41 planting beds that need to be converted. There are also a number of large beds and islands that are not lit at all. These will need new systems.

David Gretzmier
04-27-2010, 01:19 AM
hmm. islands with no lighting in a sea of asphalt. do you have outlets or power available in those islands? a diamond asphalt blade machine is not a fun day. or week.

Pro-Scapes
04-28-2010, 05:42 PM
Depending on the levels of ambient light you may want to think twice about an MR16 led retrofit. I would definatly mock up at least 1 bed.

There is a lawsuit going on in California right now where a contractor using a top name brand landscape lighting did not use the proper levels of light. A guest of the Hotel he lit fell and is suing the hotel owner. Not sure on the outcome if there is one yet but it is very important to make sure it is done RIGHT.

You may want to see about keeping the line voltage in the islands intact and using a smaller electronic transformer installed in a sealed J box or a small in grade transformer at each location OR placing a trans in 1 bed then running it to 4 adjacent beds. It would all depend on the distance and avalibility of conduits etc.

There may be simple photocells vs a timer like David is speaking of.

Steve has some excellent suggestions for you

Braphael
04-28-2010, 06:20 PM
Thanks for the comments Billy. It looks like the job may be going to the electrician that does the maintenance on the property. The management office hasn't returned any of my phone calls since friday. I have offered to set up a demo in different areas to show them what can be accomplished, but no return calls.

jshimmin
04-29-2010, 07:59 AM
You may want to see about keeping the line voltage in the islands intact and using a smaller electronic transformer installed in a sealed J box or a small in grade transformer at each location OR placing a trans in 1 bed then running it to 4 adjacent beds. It would all depend on the distance and avalibility of conduits etc.



LED and Electronic transformers don't typically mix. The square wave output of some electronic transformers will not drive the LED's rectifier correctly.
I have a similar large property that they used electronic transformers on around 150 fixtures. They want to go LED, but we have not come up with a reasonable solution yet.

INTEGRA Bespoke Lighting
04-29-2010, 09:05 AM
You can use the new Lightech LET-60LW electronic transformers to power up many LED lamps with good results. You will have to check with your LED lamp supplier or wire up a simple test to ensure the lamps fire, but I have tested these here and they work very well.

http://lightechinc.com/lightech-news/2010/2/4/let60lw-low-wattage-transformer-through-ul-low-wattage-minim.html

NightScenes
05-27-2010, 11:27 AM
I convert line voltage systems to low voltage LED quite often but you REALLY NEED to use a magnetic transformer and there are a few out there that fit into a 4x4x4 box quite well.