220 vs. 110 cost

[bb1970]

Hey all, I ran 4 metal halide fixtures on 110. They are pretty costly to run. These are muti-tap fixtures so if I swapped them to 220 would I save any $$$. Bill

 

[Speedy Petey]

Nope. You pay for watts, and that does not change, regardless of the voltage.

 

[Coach James]

Not trying to be a wiseguy, but I have always been billed for kWhrs which is Joules or amount of energy. Watts is a rate of energy usage and I'm not sure how the energy company could bill for that.

Coach

 

[Mrwinter617]

The only thing that changes is amperage. The benefit would be smaller gauge wire = more $$$ for toys

1000w at 120v requires 1000/120 = 8 amps.
1000w at 240v requires 1000/240 = 4 amps.

 

[djjsr]

.... but I have always been billed for kWhrs which is Joules or amount of energy. Watts is a rate of energy usage and I'm not sure how the energy company could bill for that.

Maybe I'm wrong but I believe the kwhrs you speak of are kilowatt hours. One kilowatt hour is 1000 watts for 1 hour.

Turn on ten 100 watt lightbulbs for 1 hour and you pay for 1 kwhr.


edit - I think I misunderstood. Do you mean how could an energy company bill just for watts without hours?

 

[kevin47]

I find the "color" of the light is lousy for shops, anyway...Unless of course your just trying to grow something with them...Consider something else...Those thin floresents come to mind...And you can get them with sensor's to turn them on an off automatically...

 

[volaredon]

I like my metal halide fixture under the gable of my garage, it lights up the front of the garage and driveway nicely with a blue/white light not such a yellow light like incandescent fixtures.

To answer the question I was always told that 240 was cheaper to run than 120 because the voltage doubles but the amps is 1/2

 

[Stuart in MN]

To answer the question I was always told that 240 was cheaper to run than 120 because the voltage doubles but the amps is 1/2

Either way the watts turns out the same (volts x amps = watts) and you pay for kilowatt-hours, so the voltage doesn't matter.

 

[Coach James]

Maybe I'm wrong but I believe the kwhrs you speak of are kilowatt hours. One kilowatt hour is 1000 watts for 1 hour.

Turn on ten 100 watt lightbulbs for 1 hour and you pay for 1 kwhr.


edit - I think I misunderstood. Do you mean how could an energy company bill just for watts without hours?

Yes. How could they bill for rate of usage instead of quantity of energy(kWhrs) used.

Coach

 

[Nostraquedeo]

Yes. How could they bill for rate of usage instead of quantity of energy(kWhrs) used.

Coach

Kilo = 1000

Like djjrs said....hook up ten 100watt bulbs and you will be using 1000watts(or 1 Kilowatt) of energy. Leave them on for one hour. You have used one kilowatt for one hour. Your billing rate like mine is based on kWhrs, so what ever your rate for kWhrs is what the ten 100watt bulbs running for one hour is gonna cost you. Probably in the $.10 range, at least for my area.

Is that clear now?

 

[Charles (in GA)]

Hey all, I ran 4 metal halide fixtures on 110. They are pretty costly to run. These are muti-tap fixtures so if I swapped them to 220 would I save any $$$. Bill

Are these 400 watts each? That is what I have. They draw right at 4.0 amps each on 120volt or 480 watts (which includes losses in the ballast in the light). Hopefully if you have them all on one circuit that it is a 12 gauge wire/20 amp breaker circuit. I have a dozen of these on three multi-wire circuits (my fixtures were 120v only, no multitap) so I did the next best thing with the multi-wire setup. I can turn on two lights in a row, or all four in a row (DPDT toggle switches) but its still a lot of current, and light, when everything is on. HERE is the thread where I installed my MH lighting, and HERE is the thread where I installed the DPDT switches to allow half of the lights to be turned on to save me some energy.

I find the "color" of the light is lousy for shops, anyway...Unless of course your just trying to grow something with them...Consider something else...Those thin floresents come to mind...And you can get them with sensor's to turn them on an off automatically...

Metal Halide is a virtually white light. I don't see that the fluorescents are enough better or different to matter. Now Sodium, that is a different story, it is either a light orange or a darker orange, depending on whether it is high pressure or low pressure, and of course, the old Mercury Vapor is a terrible bluish light and not real bright for the power consumed. Possibly you are confusing the sodium or mercury for metal halide.

I like my metal halide fixture under the gable of my garage, it lights up the front of the garage and driveway nicely with a blue/white light not such a yellow light like incandescent fixtures.

To answer the question I was always told that 240 was cheaper to run than 120 because the voltage doubles but the amps is 1/2

The only way it could be cheaper, and only an insignificant amount cheaper, is that, if the wires are not sized properly, you could have "line losses" (ie. heating of the wires) and that consumes extra energy, but you would really have to have way too many lights on a circuit to have that happen.

First pic is a comparison of 8 bulb (54 watt "4 ft") T5HO fixtures on the left with pairs of 400 watt Sodium on the right. The complete conversion to the T5HO fixtures cut the electric consumption by exactly half, as each 8 bulb T5HO fixture draws what the two 400 w sodium lights drew. One T5HO fixture replaced two of the sodium.

Next pic is all twelve of my MH lights on plus two 500 watt quartz floods on the back wall.

Charles

 

[duude]

You can save $ on material by sizing your lighting load at 240v for wiring and breaker(s). Running small control wiring to switches from contactors. Can buy used or surplus contactors, (relays) off eBay reasonably. Depending on building.

 

[Coach James]

Kilo = 1000

Like djjrs said....hook up ten 100watt bulbs and you will be using 1000watts(or 1 Kilowatt) of energy. Leave them on for one hour. You have used one kilowatt for one hour. Your billing rate like mine is based on kWhrs, so what ever your rate for kWhrs is what the ten 100watt bulbs running for one hour is gonna cost you. Probably in the $.10 range, at least for my area.

Is that clear now?

It was never unclear. My first post was was a diplomatic way of stating that people are not billed watts but for Joules which is what kWhrs are equvalent to. The energy company bills for the amount of energy used, not the rate of usage.

Yep, our cost is ~ 10 cents per kWhr too.

Coach

 

[Charles (in GA)]

A kwhr is a rate of usage, as a form of work performed. A watt, without qualifying it for the amount of time doesn't indicate the rate of consumption.

"The energy company bills for the amount of energy used" you said it. Just like buying a tank of gas.

Charles

 

[DekeT]

A kwhr is a rate of usage, as a form of work performed. A watt, without qualifying it for the amount of time doesn't indicate the rate of consumption.

"The energy company bills for the amount of energy used" you said it. Just like buying a tank of gas.

Charles

I am fairly cetain that speedy petey was just being in a hurry when he did not add the time to watts.

 

[Speedy Petey]

It was never unclear. My first post was was a diplomatic way of stating that people are not billed watts but for Joules which is what kWhrs are equvalent to. The energy company bills for the amount of energy used, not the rate of usage.

Yep, our cost is ~ 10 cents per kWhr too.

Coach

You're an engineer, aren't you?

 

[Nostraquedeo]

It was never unclear. My first post was was a diplomatic way of stating that people are not billed watts but for Joules which is what kWhrs are equvalent to. The energy company bills for the amount of energy used, not the rate of usage.

Yep, our cost is ~ 10 cents per kWhr too.

Coach

Oh, you're just trying to muddy the water, I see now. So you knew what was implied, but instead of saying "You mean kWhrs not watts".....You thought it would be more fun to get technical with the semantics of it. This kinda thing turns threads south and does nothing but confuse people. To each their own though..........

 

[Coach James]

You're an engineer, aren't you?

Lol. No. But I do get your drift.

Coach

 

[Coach James]

Oh, you're just trying to muddy the water, I see now. So you knew what was implied, but instead of saying "You mean kWhrs not watts".....You thought it would be more fun to get technical with the semantics of it. This kinda thing turns threads south and does nothing but confuse people. To each their own though..........

No. It's not semanatics to me. Watts is one thing and kWhrs is something different. I don't come on here and try to start dustups with people.

Coach

 

[nehog]

Not trying to be a wiseguy, but I have always been billed for kWhrs which is Joules or amount of energy. Watts is a rate of energy usage and I'm not sure how the energy company could bill for that.

Coach

Maybe I'm wrong but I believe the kwhrs you speak of are kilowatt hours. One kilowatt hour is 1000 watts for 1 hour.

Turn on ten 100 watt lightbulbs for 1 hour and you pay for 1 kwhr.


edit - I think I misunderstood. Do you mean how could an energy company bill just for watts without hours?

OK, I'll throw a monkey wrench into this whole mess! Some commercial accounts do get charged on watts (not KWh, but watts) using what is called a peak usage rate. The meter records both KWh, and the peak demand. When the peak demand exceeds a certain level, a different rate is used. There may be multiple steps in that computation, and usually it is on a monthly basis.

 

[91bronc300]

Here's what I don't get. So a joule is a measure of energy. A watt is one joule per second, or a unit of energy per unit of time, so power. Well a kilowatt/hour is a unit of energy per unit of time per unit of time and that's a rate of change. So a kilowatt then must describe the acceleration of electrical energy through a house. But I'm pretty sure electricity stays at the same speed when it goes through your house. Doesn't it? Where did I go wrong?

 

[Stuart in MN]

It's kilowatt - hour, not kilowatt/hour. So, if one watt = one joule/second and you multiply it by one hour (or 3600 seconds) you have 1j/1s x 3600s = 3600j. The seconds cancel out.

 

[91bronc300]

Thank you sir. You're a genius

 

[Coach James]

You're an engineer, aren't you?

I had to add this as my sig. Gave me a good chuckle.

Thanks Speedy!

 

[djjsr]

But I'm pretty sure electricity stays at the same speed when it goes through your house. Doesn't it?

Yup. Electricity travels at the speed of light. Even if the extension cord is a tangled mess, it won't slow it down.

 

[nehog]

Yup. Electricity travels at the speed of light. Even if the extension cord is a tangled mess, it won't slow it down.

Now I'm really going to hurt everyone's head. Electrical force moves at (about) the speed of light. Electrons themselves move much slower!

If anyone wants, I can post a writeup that I did a few years back on that topic for a book I was working on. I described just how long it would take a given electron to go from the brake switch to the brake lamp in a car if the wire was 20 ft long.

Anyone want to guess how long?

 

[Coach James]

I'll take a guess. ~85 hours?

Coach

 

[DekeT]

Now I'm really going to hurt everyone's head. Electrical force moves at (about) the speed of light. Electrons themselves move much slower!

If anyone wants, I can post a writeup that I did a few years back on that topic for a book I was working on. I described just how long it would take a given electron to go from the brake switch to the brake lamp in a car if the wire was 20 ft long.

Anyone want to guess how long?

Just over 7 hours.

 

[djjsr]

20 nanoseconds.

 

[91bronc300]

Just under 7 hours?

 

[nehog]

Bulb power: about 100 watts, about 100V at 1AOK, let's change the numbers a bit. Instead of 12 volts, let's get some numbers that are a bit easier to work with. We'll make it a 100 watt light bulb. We can use 100 volts (DC) which will result in a current of 1 ampere. In the end we must use a relatively simple formula to do our computation.

We know the following:

• Our current (voltage is unimportant): I = 1 ampere
• We need to work in metric (much easier!) so we make our wire have a diameter of: D = 2/10 cm, and this gives us a radius R=.1cm
• Mobile electrons per cc (for copper, if 1 per atom): Q = 8.5*10^+22 (use different types of wire, this changes...)
  
• Charge per electron: e = 1.6*10^-19 (this is pretty much a given!)
• pi is 3.1415926
  

The equation (solved):

cm/sec =   ________I_______  = .0023 cm/sec  =  8.4 cm/hour  
           Q * e * R^2 * pi

(OK I tried putting numbers there, but things get messy with the editor!)

We know current is a factor, the above example is fudged to use easy numbers and make for an easy solution. For those not used to engineering, 8.4 CM an hour is very, very slow! It is about 3.22 inches an hour. So to go 20 ft, we're talking about 75 hours! So the 84 hour guess is the closest one so far.

 

[kbs2244]

On a whole different plane of reference.
Those are industrial style lights.
What is the chance of the 220 mentioned on the label being one leg of a 440 feed?

As I understand it, there is no electric cost saving.
Just installation cost saving on wire size for the load.

 

[Charles (in GA)]

On a whole different plane of reference.
Those are industrial style lights.
What is the chance of the 220 mentioned on the label being one leg of a 440 feed?

As I understand it, there is no electric cost saving.
Just installation cost saving on wire size for the load.

That would be 277 volt if I recall correctly, and the feed would be 460v, not 440v. Very common to find 277v lighting in industrial and commercial.

Charles

 

[Alchymist]

Duplicate post. Sorry!

 

[Alchymist]

Yup. Electricity travels at the speed of light. Even if the extension cord is a tangled mess, it won't slow it down.

Not quite. Depends on the type of conductor, but no electron flow in a conductor reaches the speed of light. None, Nada! And, a tangled extension cord WILL slow it down. Perhaps not enough to measure without sophisticated instruments, but it will slow it down.

 

[91bronc300]

Bulb power: about 100 watts, about 100V at 1AOK, let's change the numbers a bit. Instead of 12 volts, let's get some numbers that are a bit easier to work with. We'll make it a 100 watt light bulb. We can use 100 volts (DC) which will result in a current of 1 ampere. In the end we must use a relatively simple formula to do our computation.

We know the following:

• Our current (voltage is unimportant): I = 1 ampere
• We need to work in metric (much easier!) so we make our wire have a diameter of: D = 2/10 cm, and this gives us a radius R=.1cm
• Mobile electrons per cc (for copper, if 1 per atom): Q = 8.5*10^+22 (use different types of wire, this changes...)
  
• Charge per electron: e = 1.6*10^-19 (this is pretty much a given!)
• pi is 3.1415926
  

The equation (solved):

cm/sec =   ________I_______  = .0023 cm/sec  =  8.4 cm/hour  
           Q * e * R^2 * pi

(OK I tried putting numbers there, but things get messy with the editor!)

We know current is a factor, the above example is fudged to use easy numbers and make for an easy solution. For those not used to engineering, 8.4 CM an hour is very, very slow! It is about 3.22 inches an hour. So to go 20 ft, we're talking about 75 hours! So the 84 hour guess is the closest one so far.

So current, being the only thing in the numerator, has a large effect on the speed of an electron. So lets see if I can do the math right, if you run that 100W bulb with the 13.5V of a running car the amps jump up to 7.41 or .017 cm/sec or 61.35 cm/hour or 9.94 hours to go 20 feet. If the car is off and the battery is supplying 12V then amps jump to 8.33 or .019 cm/sec or 69 cm/hour or 8.83 hours to go 20 feet.

Is that math right or way off base?

 

[djjsr]

Not quite. Depends on the type of conductor, but no electron flow in a conductor reaches the speed of light..

As an electron enters one end of a conductor another (different) electron exits the other end. This process occurs at the speed of light.

That's my story and I'm stickin' to it.

(until somebody with a PHD in physics explains otherwise)

 

[Norcal]

That would be 277 volt if I recall correctly, and the feed would be 460v, not 440v. Very common to find 277v lighting in industrial and commercial.

Charles

If 460V, it would be 265V, not 277V, 460Y/265V is a real odd beast.

 

[Coach James]

Nothing with mass can ever reach the speed of light, but when I worked at Jefferson Lab, electrons were being accelerated to over 99% the speed of light.

Coach

 

[0.511MeV]

I love conversations about high speed particles! That's why my screen name is electron.

Just for fun, did everyone know that an electron can travel faster than the speed of light.......in a medium? Water is a great example of a medium where that is possible. Nuclear reactors produce high speed electrons that exceed the speed of photons (particles of light) in the cooling water. The result is something called Cerenkov radiation, which is a blue glow around the core.