Latest Project - Contractor Talk - Professional Construction and Remodeling Forum

SOUTHERN LITES · 03-06-2008, 08:52 PM

My latest project is for a townhome community. The center of the project is a lake with a sidewalk surrounding it. We are lighting the walk with 43- 20 watt path lights. There is 1200' to cover around the lake. There is one corner of the lake that will not be lit, so we are really only lighting about 1000'. The fixtures are spaced out roughly 24' apart.

Any suggestions on transformer sizes and wire size?

Thanks,

TDLMN · 03-07-2008, 03:33 PM

Steve...where is the 120v power located in reference to the location of the fixtures? One power source, two, or more? What wiring technique will you be using? I would be happy to help you but I need a little more info.

Best, GD
President
Terradek Lighting Inc.
800-609-1130

SOUTHERN LITES · 03-07-2008, 05:34 PM

There are 2 power sources at opposite ends of the lake. I was going to wire using the T method. If you need any more info. let me know.

Thanks,

TDLMN · 03-17-2008, 05:07 PM

Steve,
Sorry for not getting back sooner...That is good news, having two power sources will help alot with the distances that you are dealing with. Are you comfortable calculating voltage drop? Because the first step is to determine how to get the right amount of voltage to you fixtures...I will calculate this for you and give you a plan in the morning.

til then,
gerry.

TDLMN · 03-18-2008, 08:58 AM

Steve,
This project needs two transformers. Each should have voltage capability of 18 or 19 volts. The wattage requirement should be a minimun 840w to 900w. This project can be done in 12 gauge wire.

Each transformer will have four runs that lay out as follows:
Transformer 1:
r1= 75' @ 100w (five 20w lamps) 14vtap = 116.62w (e) or 9.72amps.
r2 = same as above
r3 = 225' @ 100w = 19vtap =158.27w (e) or 13.19 amps.
r4 = same as above

r1 & r2 on circuit #1
r3 on circuit #2
r4 on circuit #3

Transformer 2 would lay out the same

Understand that these are desk estimates based on incomplete information. Actual field measured results will be different. This plan accounts for 40 of the 43 fixtures, I do not know how you want to split the remaining three fixtures up but I would say they can go on any of the above runs, my preference would be to put them on r3 or r4 and split them between t1 and t2. What is clear though is that 12 gauge wire will do the job and that your effective wattage will be impacted by having to use higher voltage settings.

Given the fixture spacing in your layout I would consider using the "LOOP" wiring technique to achieve the best balance of voltage to your fixtures. The "t" technique will not be as good given the distance from the mid fixture to the last. If you are unfamiliar with the loop technique let me know and I will explain. I hope that this helps...

Best,
Gerry De La Vega
Terradek Lighting Inc
1-800-609-1130
terradek.com

SOUTHERN LITES · 03-18-2008, 12:52 PM

Gerry,

Wow, I appreciate the help with the voltage drops. I had done alittle figuring on my own and was having trouble with the T method. The distance from the T to the end, to get the proper voltage at the end I was usually to hot at the T. This was happening on some of the runs not all of them. The lay-out of this lake project is kinda lop sided and hard to explain with my limited vocabulary skills.

The loop method would suit this type situation better than the T method for what reasons? ( learning opportunity )

I have another question a bit off topic if your interested.

When you were first starting in the lighting business what did you find to be the best form of advertisement. Which had the best return?
Any advice for approaching a dock builder and offering lighting services for his docks? I live on the Florida gulf coast so there would be plenty of opportunity.

I do appreciate you taking the time to answer some of my many questions.

Thanks,

TDLMN · 03-18-2008, 02:30 PM

Steve,
The Loop more evenly distributes voltage to each fixture on a run, whereas the "t" will always be hottest at the first fixture and less so at the ends of the "t". The only thing about the Loop, if you don't already know, is that you must maintain polarity in your run throughout the loop. Let me know if you need more explanation on this.

As to starting your business...When I was a contractor, I found that my biggest payback was to market to landscapers. They will bring you leads that will close 80% - 90% of the time. I would give them a finders fee for every job that sold, usually 10% of the sold price. It was the first check I cut each month. Just go to your local yellow pages and call each landscaper listed and ask if they do lighting...if they don't, find out what they are doing with the requests that they are getting from thier customers. Tell them that you are willing to be thier lighting guy and pay them for the priviledge...If they do lighting ask if they would like to make money on lighting without having to use any of thier resources. Usually lighting is a headache for landscapers due to thier high overhead costs, maintenance issues, and lack of knowledge.

Whenever you do a job send a letter to each address on the block letting them know that you will be working in the area and that if there are any issues to call your cell #. This gives a potential customer the impression that you are a professional with integrity who cares about what they are doing...it also lets them know who did the job that they will be driving past each day...of course do not forget to put up your yard signs. Don't waste your money on Yellow Pages or Home & Garden shows...Big waste of time and $$$. If you are going to do H&G shows allign youself with a landscaper or two who are setting up a display and offer to light it for him/her. Put your cards in the booth and enjoy your day doing something else. We often would do three or four displays for landscapers at no cost to us and with great results. Your landscaper will like the added touch to thier booth and you will benefit from the referrals. To make real money in this business you must get to the point where each of your leads is coming from a referral...if you have to go find each new customer you will always suffer.

I can send you brochures on Dock lighting products that you can bring to your dock builders and offer to install them for customers who may want to add them to thier new dock. Same as the landscaper scenario, they get a cut from your sales. Remember to always increase your sale price to accomodate the referral fees you are going to pay. Never take it out of your profit margin. I hope that this helps...

Best,
Gerry De La Vega
Terradek Lighting Inc.
1-800-609-1130
terradek.com

SOUTHERN LITES · 03-18-2008, 03:30 PM

Gerry

That helps alot!!

Steve

SOUTHERN LITES · 03-18-2008, 04:08 PM

Gerry,

About that loop method. What are the length limts with using the loop method. Do you end the loop at the first fixture in the run? How do you check the polarity before final termination?

Let me know if I start to wear you out.

thanks,

SOUTHERN LITES · 03-19-2008, 08:59 AM

Gerry,

I have done a search on transformers and I haven't really found what I am looking for. I would like to know why you choose a certain T/F versus another. Are you sold on one manufacturer? Out of the top makes Kichler,Vista,Unique, Cast,...etc are there any major differences in quality or capabilities? lastly why would you not use ABC or XYZ brand?

Thanks in advance,

TDLMN · 03-19-2008, 10:36 AM

The maximum length of a run is determined by the wattage requirement on the run, and the voltage setting necessary to power the fixtures to 10.8 - 12.0 volts. What I mean is that there is no hard and fast rule, because it is a function of many things. The one thing that must never be exceeded is the Max. amps on your run...this is what determines the max. distance, and as you know amps are determined by wattage/voltage. The maximum amps on 12 gauge wire is 20A. So no matter how far your run is 10' or 500' the max amps should not exceed 20A, For 10gauge cable the max amps is 30amps. The problem with using 10 gauge is that the max capacity of a 300w circuit is 25amps (300w/12v = 25A). So even though the cable is rated for 30A you can only output 25A from a 300w circuit, in essence you are paying for more cable than you can use. On my previous post I calculated amps for each run so that I could plan for the number of 25amp circuits I would need to accomodate the system. It is one of the things that I look at when deciding the size of transformer I will need. Sometimes I will need a larger transformer just to accomodate the amp load that I will be generating on my runs. That is also how i decide which runs to put on each circuit. If you look back at the previous post you will notice that the only runs I could put on the same circuit were r1 and r2 because when I added them together they were less that 25amps. I could have put r1 and r3 together but I would have been at 22.91amps which is too close for comfort for me. I like to keep my amps to 20 or less on each circuit to accomodate for actual field conditions that may effect my estimates.

There are two acceptable methods to create a loop...one is to loop back to the transformer, the other is to loop back to the first fixture in the loop. My personal preference is to loop back to the first fixture in the loop. Why go all the way back to the transformer? More expense in wire and more wires in the transformer to deal with are two major reasons not to take the run all the way back to the transformer.

The easiest way to maintain polarity is to match your cable at every connection...what I mean is that each run of cable has two halves, one leg of the cable has writing on it, or has ribs. The other half of the cable has no writing or is smooth to the touch. The best way to maintain polarity is to match writing to writing or ribbed to ribbed at each connection point. The fixtures do not have any polarity requirement so either leg of the pig tail can be attached to either leg of the cable. You will know right away if something was connected wrong as you will short the system immeadiately.

Steve I never tire of helping people who want to learn more about this wonderful profession of ours. I want to help you be successful in this business and I want your systems to be flawless so that your customers tell thier friends about what a wonderful addition Landscape Lighting was to the enjoyment of thier property. If we do this, we will continue to grow the market for all of us.

Good Luck...

Best,
Gerry De La Vega
Terradek Lighting Inc.
1-800-609-1130
www.terradek.com

TDLMN · 03-19-2008, 10:46 AM

I carry 30 different manufacturers because each brings a little something different to the party...with regards to trans. yes there are many differences that I look at when choosing the right product for the situation. I could go on for hours describing the differences between boxes but suffice it to say that not all transformers are created equal. Be very wary of off brands...the transformer is the heart of the system do not be penny wise and pound foolish. Selecting the wrong box is the start of a long and troublesome system.

In your particular application the one critical feature of the transformer is the voltage capability you will need to address the voltage drop you are going to experience. Only a few transformers will have an 18 or 19 volt setting. That feature is essential to your particular situation.

Best,
Gerry De La Vega
1-800-609-1130
www.terradek.com
Terradek Lighting Inc.

NightScenes · 03-19-2008, 04:02 PM

Gerry, this is one of the reasons I do business with you. You are one of the best distributors in this business!! Keep up the good work and keep that education coming!!