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#60587 - 01/05/06 09:20 AM not sure ?
drgnz23 Offline
Member
Registered: 02/17/02
Posts: 56
Loc: los angeles
Hey guys im not an engineer so many you can help me. We have to run some pole lights a span of 500 feet. They are 150 watt each 100 feet apart. I understand my voltage will be affected by the lenght. Im just not to sure what size wire to run. To make it interesting we have to pick up 5 other lights but we might just pull new homerun for those. Those light are 500 feet away and span 240 ft ( 60 ft apart) PLease help. I usually just listen to the boss, usually dont do my own projects.
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#60588 - 01/05/06 09:30 AM Re: not sure ?
iwire Offline
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Registered: 01/05/03
Posts: 4391
Loc: North Attleboro, MA USA
We can definitely help but you left out the voltage which is necessary to know.
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Bob Badger
Construction & Maintenance Electrician
Massachusetts
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#60589 - 01/05/06 09:32 AM Re: not sure ?
GETELECTRIC Offline
Member
Registered: 10/22/03
Posts: 172
Loc: toronto canada
You can find out voltage drops on certain sites.
Such as:Electricians toolbox(enter as a search)
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#60590 - 01/05/06 09:43 AM Re: not sure ?
drgnz23 Offline
Member
Registered: 02/17/02
Posts: 56
Loc: los angeles
just realized a i left out the volatge 120v
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#60591 - 01/05/06 09:50 AM Re: not sure ?
iwire Offline
Moderator
Registered: 01/05/03
Posts: 4391
Loc: North Attleboro, MA USA
OK there are many ways to do it, the most accurate would be point to point.

That means figuring the VD separately for each segment.

However your total load is low 5 x 150 watts or 6.25 amps so you might do fine by figuring 6.25 amps at 250' out.
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Bob Badger
Construction & Maintenance Electrician
Massachusetts
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#60592 - 01/05/06 10:03 AM Re: not sure ?
drgnz23 Offline
Member
Registered: 02/17/02
Posts: 56
Loc: los angeles
So your saying it would be okay to run 8 awg wire through the whole lenght? Thats a span of 500 ft.
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#60593 - 01/05/06 02:16 PM Re: not sure ?
frenchelectrican Offline
Member
Registered: 02/06/03
Posts: 939
Loc: Wi/ Paris France { France for ...
you can use #8 thwn type but the vd will be about 5% but i ran with my figures i keep my vd to lower numbers i came up with # 6 size because you did not figured the ballast loss so i add little more leeway on it the VD is 2.7% [3.2 v]

if the building power supply have 120/240 or 120/208 i will try to run higher voltage if possible to keep the VD more lower

this what i came up if wired for 240 volts with the same number of fixures for 500 feet run my figures show can use #12 wire. the same thing if wired for 277 volts too can use #12 also but i will suggest is check the design lay out to see the best run with least amout of wires if nessecary.

i am sure most parking lot lumiaires useally have mutitap ballast you can wire on higher voltage if the sisuation called for.

if more question you can drop the line here


Merci , Marc
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Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)

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#60594 - 01/05/06 02:58 PM Re: not sure ?
drgnz23 Offline
Member
Registered: 02/17/02
Posts: 56
Loc: los angeles
wee wee . Hey thanks for the help. I guess we figured we run 8 awg for the closes set of lights then we would do the farthest ones with 6 awg. We also consired running 240 v .Thank you guys for the help.
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#60595 - 01/05/06 03:04 PM Re: not sure ?
iwire Offline
Moderator
Registered: 01/05/03
Posts: 4391
Loc: North Attleboro, MA USA
If you have the choice by all means use 240.

Always use the highest voltage available for long circuits.

Without running the figures I bet you would be back to 10 or maybe 12 AWG as Marc pointed out.

[This message has been edited by iwire (edited 01-05-2006).]
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Bob Badger
Construction & Maintenance Electrician
Massachusetts
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#60596 - 01/05/06 03:46 PM Re: not sure ?
frenchelectrican Offline
Member
Registered: 02/06/03
Posts: 939
Loc: Wi/ Paris France { France for ...
qoute ; I guess we figured we run 8 awg for the closes set of lights then we would do the farthest ones with 6 awg.


i will suggest that do the other way around run the short length with #6 then half way thru the run drop down to #8

but if you can get 240 volt that will be more festible you can get by with smaller wire it will somehow cost less along the way but please do check the design carefully

Merci , Marc

[This message has been edited by frenchelectrican (edited 01-05-2006).]

[This message has been edited by frenchelectrican (edited 01-05-2006).]
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Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)

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