Which Voltage??

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  #1  
Old 01-13-05, 03:28 PM
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Which Voltage??

Lighting, motors etc in a alot of cases can be wired for either 220 v or 110 v.

Other than the convenience of 110v why would you wire for 220 v.

I am specifically now talking about halide shop lighting.

What is the difference.

I can as easily wire for either.

Thanks
John
 
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  #2  
Old 01-13-05, 04:48 PM
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Voltage and amperage are directly proportional.

120v 10amps 240v 5 amps. Electric meters measure the amount of amperage that you use and that's what you pay for. If you can wire the lights at 240v, it will only cost you half as much to burn them than at 120Volts.

 
  #3  
Old 01-13-05, 05:00 PM
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Originally Posted by John1
Lighting, motors etc in a alot of cases can be wired for either 220 v or 110 v.

Other than the convenience of 110v why would you wire for 220 v.

I am specifically now talking about halide shop lighting.

What is the difference.

I can as easily wire for either.

Thanks
John
The difference is 220 volts uses 1/2 the amps for the same wattage. You could use smaller wires and breakers or put more fixtures on the same circuit. This could save money in cable costs. It won't save on electric bill. It still uses the same watts.
 
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Old 01-13-05, 05:06 PM
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Electric meters measure the amount of amperage that you use and that's what you pay for.
This should read: "..measure the amount of watts..." This is why an electric meter is called a kilowatthour meter. It measures kilowatts per hour.
 
  #5  
Old 01-13-05, 06:25 PM
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I stand corrected. Why 277 lighting ???
 
  #6  
Old 01-13-05, 06:53 PM
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Little confused.

Does it or not cost less when wired 220 vs 110??

John
 
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Old 01-13-05, 06:57 PM
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....Not...
 
  #8  
Old 01-13-05, 07:05 PM
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So what is the benefit
 
  #9  
Old 01-13-05, 08:17 PM
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Operating cost: same
Panel space: 120 uses half the space
Fixture cost: 120 fixtures usually cheaper
Safety: 120 a little safer
Wire size: 240 allows cheaper wire
Availability: Residential fixtures more readily available in 120
Voltage drop: 240 has less voltage drop for the same power

Bottom line is that the choice usually swings on the costs at installation time.
  • 240 is commonly used only in applications where the power need is high, and/or when the wiring distance is great. This primarily is because the wire costs are significantly reduced with 240.
  • When the power needs and wire distances are moderate, the choice favors 120 because fixture costs and breaker/panel costs outweigh wire cost.
 
  #10  
Old 01-13-05, 08:26 PM
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Thanks again John

I will go with the 110v for the halide low bay lights.

John
 
  #11  
Old 01-13-05, 08:32 PM
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Just one example.

watts = amps X volts

A 12 ga wire is good for 20 amps.

120 volts X 20 amps = 2400 watts

240 volts X 20 amps = 4800 watts
Its best to stay 20% lower then the max.

Using 240 volts with 12 ga wire you can run a larger heater (4800watt) with out
the need of increasing the size of the wire (up to 20 amps on 12 ga wire).

On 120 volts a 4800 watt heater will require 40 amps and larger gauge wire.

12 ga wire cost less then 8 ga wire.

You need to calculate the amount of watts your lights will need, on each run.
And what's the Length of the run.
Long runs create voltage drops.
If the run is long use 240 volts.

I would run motors with the higher voltage they will start easier.(more starting power)
 
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Old 01-13-05, 10:36 PM
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Some 240v applications need double pole switches; they're uncommon and expensive.
 
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Old 01-14-05, 04:58 AM
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Very good point. In general, _all_ ungrounded conductors must be disconnected by a switch. (There are exceptions, for example a single pole thermostat when combined with a separate two pole disconnect....) If you use 240V for lights, you will have to use double pole switches.

In larger commercial applications, 277V 'single phase' is used for lighting. Since this is 277V line to neutral, only a single pole switch is required. However you need a 480V/277V wye transformer feeding your building....not common in a home In these larger applications, the 277V is a big savings; you use half the wire you might otherwise need.

-Jon
 
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Old 01-14-05, 05:20 AM
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Originally Posted by Kobuchi
Some 240v applications need double pole switches; they're uncommon and expensive.
They are not at all uncommon and I really wouldn't call them expensive, especially 15 and 20 amp'ers. OK, maybe compared to a $.59 snap switch.
 
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Old 01-15-05, 10:41 PM
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208 and 277 are the single phase voltages found in different types of 3-phase power found in large properties, especially commercial and lodging. ( If I remember correctly, 208 is from a 120 volt wye and 277 is from a 480 volt delta, but I am open to correction on this).

It has been well-explained by previous posters that higher voltage gets you the same WATTS to a lamp at lower total current draw, hence smaller wire. Wire cost is directly related to size, and labor also tends to be higher with larger wire, so these things all lead to a preference to higher voltages when possible.
 
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Old 01-18-05, 12:21 AM
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Originally Posted by Speedy Petey
They are not at all uncommon and I really wouldn't call them expensive, especially 15 and 20 amp'ers. OK, maybe compared to a $.59 snap switch.
I should have said there's less selection, then:

http://www.doityourself.com/store/si...leswitches.htm (45 single pole)
http://www.doityourself.com/store/do...leswitches.htm (3 double pole)

John1 wouldn't have trouble finding DP switches appropriate for shop lighting, anyway. Home Depot stocks one.

And the basic switch price times ten? If you think the price difference trivial I'm open to a trade.

***

Another advantage with 220 volts is the load balancing. This can make a difference with a small shop subpanel and inconsistent usage, where drawing exclusively off just one leg by chance, and overtaxing it, is a real possibility.
 
  #17  
Old 01-19-05, 04:48 AM
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Originally Posted by 594tough
208 and 277 are the single phase voltages found in different types of 3-phase power found in large properties, especially commercial and lodging. ( If I remember correctly, 208 is from a 120 volt wye and 277 is from a 480 volt delta, but I am open to correction on this).
208 volts is the phase to phase voltage in a 120/208 wye 3-phase system. 208 volts is also the phase to ground voltage of the "wild" leg in a 120/240 delta 3-phase system (this is the leg generated by a rotary phase convertor in a home shop that needs 3-phase from typical 120/240 single phase power).

277 volts is the phase to ground voltage in a 277/480 wye 3-phase system.
 
  #18  
Old 01-19-05, 06:32 PM
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Originally Posted by JerryB52


I stand corrected. Why 277 lighting ???

Because 277 is easily created with a 480V grounded Y connected system which is common in commercial buildings. The voltage is 480V phase to phase and 277 V phase to ground. No special transformers are needed to generate 120V for lighting.
 
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