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  #21  
Old 12-11-2007, 07:03 PM
Chris J Chris J is offline
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Quote:
Originally Posted by James Solecki - INTEGRA View Post
Ok so we have the Nightscaping Formula, and we have the Unique Formula, and we have the Vista Formula...

Are there any other, different Voltage Drop formulas out there that people know of? Not much of a compendium unless we find more then three....

.
What am I, chopped meat? What about the Johnson Lighting formula!?
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  #22  
Old 12-11-2007, 07:09 PM
Chris J Chris J is offline
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Quote:
Originally Posted by johnh View Post
AC Circuits

For AC circuits, where AC resistance and inductive reactance are considered, the following is the IEEE Std 141 exact voltage drop formula.



where:
Vd = Voltage drop (Line to Neutral)
V = Voltage (source)
I = Current in amperes (A)
R = AC Resistance from NEC® Chapter 9 Table 9 (Ohms to Neutral)
X = AC Reactance from NEC® Chapter 9 Table 9 (Ohms to Neutral)
distance (L) is considered from the Resistance & Reactance Tables
where Ohms per unit / 1000 * L in same unit = R or X
θ = Angle of Phase Offset = Arc Cosine (device or circuit Power Factor)
Line to Line is computed by Line to Neutral VD / Sqrt(3).


DC Circuits



where:
Vd = Voltage drop
R = DC Resistance from NEC® Chapter 9 Table 8
L = Distance
I = Current in amperes (A)

K = Material Resistivity constant - 12.9 for Cu & 21.2 for Al
CM = Circular mils of conductor

These are the IEEE formulae if you've got a good calculator and a dictionary!
JH
Just tell us the web site you cut and paste it from and we can figure out the rest.
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  #23  
Old 12-11-2007, 07:46 PM
klkanders klkanders is offline
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Quote:
Originally Posted by Chris J View Post
Stop it! I think I just pissed on myself!
I am quite proud of myself......soporific was the Webster word of the day.
Compendium is so yesterday. Glad you enjoyed it Chris!
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  #24  
Old 12-11-2007, 08:04 PM
Chris J Chris J is offline
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I come more from the "Jeff Foxworthy" dictionary. These big $10 words just confuse us rednecks. See ya later, gotta go catch a gater in my pond!
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  #25  
Old 12-11-2007, 08:07 PM
irrig8r irrig8r is offline
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Your Vista rep needs to do a bit more research. why would having taps 16-22v cause wasted electricity.makes no sense?

Nate talked about the energy wasted in his book Joey. He justifies that cost of running the system by the savings in the initial materials outlay.

Electricity runs me $0.11 / KWH currently. If I doubled my use it would cost me a $0.23/ KWH. Large residential users pay more. One customer where I'm planning a job is already paying $400/ mo. for electric and gas. i don't expect power to be less expensive in the future, do you?

And yeah Vista makes a TF that is NON UL 1838 it is listed UL 506 and goes to 22v to COMPETE WITH UNIQUE!! obviously.

Yep, as I said in another post they play both sides of the 1838 fence. Just goes to show you the impact Unique is having in the marketplace.

We did not manipulate the formula to increase VD, unlike what most think we are not slimeballs looking to make an extra buck. Anyone who comes to our classes for the last 10 years knows we lead the industry in education and we always inform people based off of FACT and we prove this with volt meters and amp probes. And no we do not calibrate our own meters.

You're a class act Joey.You know I respect you and Nate. I didn't accuse you of any funny business. I admit to having once had a bias against your company, reinforced by what I was hearing from some of your competitors...

I'm more open-minded now. But even they weren't calling you slimeballs.

unbelieveable. Never been on a job that needed more than 15V HAHAHAHAHAH

Must not of ever pulled a 12/2 run more than 200 ft with 80 watts on it???? Sounds like the rep has never been on a big job. Oh wait let me guess, he uses 10/2 for those long runs.......sounds real cost effective.


Well most of the jobs I encounter have (for instance) power available at each end of the driveway, for gates and post lights at the far end, and in or near the garage at the other. Most of those aren't longer than 200 ft., so a 100 ft. run isn't unreasonable to work with up to 15 v.
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  #26  
Old 12-11-2007, 08:44 PM
Chris J Chris J is offline
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I agree that the 22v trans is not normally necessary with my installs, but sometimes a 16v tap would come in real handy. My position is that if I needed a 22v tap, the lights are WAY too far from the tranny, thus causing me to bring in the electrician for an extra power source. There have been situations in the past that have provoked me to use the higher volt transformers, however, and this is why I will always promote their existence. There is absolutely no reason why 22v should scare anyone who knows what they are doing (UL 1838 listing or not). In my opinion, this is what seperates the men from the boys. You either know how to handle your tools or you don't......simple as that.
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  #27  
Old 12-11-2007, 09:30 PM
irrig8r irrig8r is offline
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Except for the ones that don't really know how to handle them but try anyway.... I don't mean anyone here of course, but I've had to correct a lot of stupid install mistakes made by other folks out there.
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  #28  
Old 12-11-2007, 09:48 PM
irrig8r irrig8r is offline
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(continuing because I let this sit for longer than 10 minutes)

This past year that's included 3 jobs w/ multi-tap transformers where the first fixture on the run had 14 V and the customer wondered why her lights kept burning out so quickly... One had the lower voltage to the more distant fixtures and the higher voltage to the closer ones... Another had two cables installed so the hot and common went to different circuits (still ran though).

As much as distributors and manufacturers try to pass along how things are supposed to be put together, even offering various free basic workshops and seminars, there are still a lot of dummies out there that do things wrong because they either don't know any better or don't care.

When they go out of business, they leave a wake of unhappy customers who end up paying twice for a job. These are the ones I worry about doing something stupid like causing a fire and giving the industry a bad name. Not that I'm losing any sleep over it, but just saying....
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  #29  
Old 12-11-2007, 10:09 PM
klkanders klkanders is offline
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Hey Gregg, It makes you wonder thats for sure. Spending more money on the bigger trans. that they usually do not need. I for the most part use the 15v tap max but on a few occasions had one longer run w more fixtures that I used 10g on to do it right. Can it be they are taught wrong or just forget everything when they walk out the door? The problems you mentioned should not happen even with a 2 hour class if the individual has half a brain and a meter? Guess your the lucky one that gets to fix them! Take Care!
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  #30  
Old 12-11-2007, 10:12 PM
Chris J Chris J is offline
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Greg,
I am right there with you on this one! There are far too many people installing lighting than there should be. This is the main reason why I tell my customers that I am the ONLY lighting contractor in Jacksonville, Florida who holds a state license for both Florida and Georgia. No other contractor in my region can make this claim! I have spent many years, and tens of thousands of dollars toward learning my craft. There is no other person in my market that I could honestly call a true competitor, however, there will always be the thrifty homeowner looking for the cheaper way out. They, too, will ultimately become my customer when their "so-called" contractor abandons them.
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