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Old 02-28-2009, 11:28 AM   #1
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900' total 120v light posts


I was told that I now have the task of installing 5 light posts around the back yard and part of our land... Total run from panel/timer is 900'

Each lamp is set up for 5 40watt bulbs... They will be pretty much evenly spaced for the length of the run...

Sooo
1st 200' will have to handle 1000ish watts
2nd 200' will have 800 watts
3rd 200' will have 600 watts
4th 200' will have 400 watts
5th 200' will have 200 watts

Total of about 9.5-10 amps I would guess...

So what would be the best way for me to go about doing this? The lamps were already ordered and on their way, so it will be done one way or another...

Voltage loss is a concern, however 5% is probably too stringent for purely lighting needs...

What sizing should I be looking at? Should I consider dropping the sizing some as the load drops to save some $$?

Thanks for the help..
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Old 02-28-2009, 11:37 AM   #2
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900' total 120v light posts


You can step the wire size down after the first run, but you may just by two sizes and be done. #8 to the first post and #10 to each after that.

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Old 02-28-2009, 12:16 PM   #3
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900' total 120v light posts


I would use small wires to get some more voltage drop to greatly lengthen the life of the (incandescent) lamps, while observing the max. insulation temp. restrictions (unless you want to put an outlet somewhere along the string or unless this tactic is forbidden by the NEC).
If you are near the pole 'former you may already have a problem with burning out lamps.

Last edited by Yoyizit; 02-28-2009 at 12:23 PM.
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Old 02-28-2009, 12:27 PM   #4
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900' total 120v light posts


1000w for outdoor lights...Wow

How about installing CFL's instead?
If you like a yellow light buy the normal CFL's
If you like a brighter light buy the Daylight bulbs
They do have bulbs that look just like a normal bulb

40w Equiv in CFL uses 9w!!
So 45w per fixture x5 = 225w TOTAL!!
Problem solved - use #12 wire (due to Voltage drop - use #12)

1st 200' will have to handle 225 watts
2nd 200' will have 180 watts
3rd 200' will have 135 watts
4th 200' will have 90 watts
5th 200' will have 45 watts

You could even step up to 60w equiv CFL = 13w
So 65w per fixture x5 = 325w TOTAL!!
1st 200' will have to handle 325 watts
2nd 200' will have 260 watts
3rd 200' will have 195 watts
4th 200' will have 130 watts
5th 200' will have 65 watts

I have tried all different CFL bulbs & we like the Daylight bulbs for Main rooms. Reg bulbs for laundry & other areas

Last edited by Scuba_Dave; 02-28-2009 at 12:30 PM.
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Old 02-28-2009, 12:46 PM   #5
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900' total 120v light posts


Quote:
Originally Posted by Scuba_Dave View Post
How about installing CFL's instead?
But check the minimum CFL starting temp. The last bunch I got says they will start at -27℉; we'll see. . .
http://en.wikipedia.org/wiki/Compact_fluorescent_lamp
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Old 02-28-2009, 01:05 PM   #6
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I use them outside all thru the winter
I have over 200 in use as part of my Christmas display
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Old 02-28-2009, 01:09 PM   #7
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900' total 120v light posts


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The last bunch I got says they will start at -27℉; we'll see
The ones I have do start cold, but have a long...... warm up time.

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Old 02-28-2009, 01:47 PM   #8
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900' total 120v light posts


CFLs are your friend in this installation!
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Old 02-28-2009, 03:05 PM   #9
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900' total 120v light posts


Quote:
Total of about 9.5-10 amps I would guess...
900' at 120 volts and 3000 watts (25 amps) is not something you want to do if I'm adding your figures correctly..... not sure though if you are getting 9.5 to 10 amps.

What you are doing is a perfect use for multiwire branch circuits using 2 hots and shared neutral at 240 volts calculated toward your VD. Giving you a big advantage in voltage drop by providing two 120 volt circuits using a shared neutral and providing you the advantage of neutral current cancellation.... if you balance the loads between the hot wires you will have only a fraction of the amps returning on the shared neutral as compared to 25 amps with all lights operating on a single run at 120 volts. This greatly reduces voltage drop which is a calculation to the farthest load and back... in your case 1800' if you only run one 120 volt circuit.

My advice would be to check your load center to see if it will accept 2 double pole breakers and if not run a small sub-panel for these oudoor lights. Put two double pole breakers in the sub panel ( a small 4 space panel would be perfect) or in the main panel. Run one 15 amp multiwire to the lights on the first 400 feet and 1800 watts (7.5 amps each hot leg) and then balance 900 watts to each hot wire....use 12 awg protected by a double pole 15 amp breaker.
On the 2nd multiwire at 600 feet and 1200 watts (5 amps each hot leg) balance 600 watts to each hot leg. Use 10 awg and a 15 amp double pole breaker.

You will have to check the shortest distances for two runs as the above is just an example using a 400 foot run and a 600 foot run measured from the panel...the actual distances will have to be determined.. Using cfl's and reducing your amperage helps the over all voltage drop for the runs. I based the above on your figures.
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Old 02-28-2009, 03:05 PM   #10
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Quote:
Originally Posted by Speedy Petey View Post
CFLs are your friend in this installation!
But women may want "soft" light.
In GeekSpeak, their Utility Function for "utility" vs aesthetics is not very positive.

My one gas lamp costs me $27/month (but it doesn't mind the cold).

And if your lights are daisy chained vs. a star pattern there are different costs for the copper.

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Old 02-28-2009, 03:44 PM   #11
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Quote:
Originally Posted by Yoyizit View Post
But women may want "soft" light.
In GeekSpeak, their Utility Function for "utility" vs aesthetics is not very positive.
These are outdoor pole lights. Who cares what women want. (Sorry gals).

Also, if "soft" light is what was wanted then WHY fixtures with three lamps?

Use smaller CFLs if they are too bright.
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Old 02-28-2009, 03:52 PM   #12
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Quote:
Originally Posted by Speedy Petey View Post
Who cares what women want. (Sorry gals).
I hope you own a comfortable sofa.

Freud didn't know "what women want", but one way to find out what they don't want is to not ask them first!

http://www.imdb.com/title/tt0207201/
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Old 02-28-2009, 03:58 PM   #13
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I hope you own a comfortable sofa.
Oh yeah. And I wear cherry flavored socks too.
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Old 02-28-2009, 03:59 PM   #14
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Quote:
Originally Posted by Speedy Petey View Post
These are outdoor pole lights. Who cares what women want. (Sorry gals).

Also, if "soft" light is what was wanted then WHY fixtures with three lamps?
Use smaller CFLs if they are too bright.
Actually 5 posts & EACH one takes (5) bulbs
THAT is not soft light, that's bright
Using 5 9w CFL's will provide soft light
You can then go up to (5) 13w CFL lights
Too soft switch to the daylight bulbs

Connect one post with a plug
Put it out in the yard as a temp setup - tie it to a bush/tree/stake
Then try the CFLs to see what wattage/daylight/reg you like

My wife really likes the CFL's
I generally install a 2nd light fixture now for more light

Laundry used to have one 75w reg bulb (also served stairs)
I now have (2) CFLs. one is 9w, the one over the laundry is 13w
Boiler room I did the same thing

I have (3) 4' Flour fixtures that use almost 300w
Not enough light in the basement
I'm going to take them out & spread maybe 12 can lights around using 9w CFL = 108w total & light will be more spread out
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Old 03-01-2009, 01:24 AM   #15
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900' total 120v light posts


I will agree with other guys go with CFL bulbs they last much longer than most indescent bulbs are and they will use far less power wattage wise.

In my house I have 4 HID post lights { 50 watts MH } they light up pretty nice bulblife they are not too bad they are right on par with good set of CFL's but only reason why I went MH's due they can able lit up nice in cold weather.

Merci,Marc

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