Does Running 240V save you money or your electricity bill??

Quite simple question, I've asked several fellow electricians and electrical teachers the same question, I really never got a straight answer...

Does Running 240V save you money or your electricity bill??

I know most people want to say "yes" do to "hear-say"

But lets examine that question:

When you step up the voltage from 120V to 240V it drops your amperage in half, which also mean you can drop you conductor (wire) size down by half. (However in most cases you need an extra conductor to achieve 240V- 2 hots a neutral and a ground (Black, Red, White, and Bare Copper))

Anyway, Increasing the the voltage, thus dropping the amperage, Doesn't change the wattage...Power Companies charge by the Kilo-Watt Hour.

Elite

Nope, math keeps ending up the same, no savings... One exception is large electric motors spin up easier on 240v but I doubt it would translate to much when the bill comes.

HID ballast inductors are more efficient on 220/240V US

220 lets you run less amperage that is all. 8 amps becomes 4 amps for instance....

DOES NOT translate to any savings in electricity usage

lot of confused "marijuana INCers" out there, do some real research please

Habibi said:

220 lets you run less amperage that is all. 8 amps becomes 4 amps for instance....

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Thanks for repeating what I said in laymans terms...However its 240V...either your an old school electrician, or not one at all...

Habibi said:

DOES NOT translate to any savings in electricity usage

lot of confused "marijuana INCers" out there, do some real research please

Click to expand...

Whow, Whow, Whow....

I'm an electrician of 12 years, asked several Master electricians and as stated Teachers (also Masters). I never got a good answer....A lot of people are confused (someone asked me this question, I didn't know, hence the thread)
Do we not start threads to learn and teach??

Elite

Running your lights 240v, will save you money because it helps equalize the load. If you run all your light 120v off the same lag you create an imbalance which most utilities charge a surcharge for.

my friend was explaining it all to me the other day, but it was well beyond my comprehension. Too bad hes not on ICMAG, hed be able to chime in and set us straight

PeteWeedSeed said:

I rate you... the most useless post of the day!

haha... thanks for the info... and I know all about power, your friend can't teach me anything.

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lol


From the crazy way he explained it to me... Depending on youre area/ and usage... 240 can save you SHITLOADS on youre bill.
I just wish i could explain to you why

PeteWeedSeed said:

What?...

Power is sent to your house at 220V then split inside your house to 110V.. They don't know which voltage your running.

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Hes obviously referring to balance of the phases. However even if the power company monitored (charged) for that, just balancing out that draw sure doesn't balance out the rest of the panels draws to phases.

Pet peeve of mine is that 110V/220V. Ever use a meter?? I've seen a wide range of draws, always within 2-4% of 120V/240V...

Old "Nob and Tube" wiring was probably 110V/220V

Elite

PeteWeedSeed said:

Especially if your in Canada, the voltage completely doesn't matter, amperage use is not monitored here.

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Same here in US...So question is answered, pertaining to Canada and US...

It CAN save you money in wire (size)...Not your electricity bill...

Thanks Everyone,

Elite

2X1

2X1

i always ran 1 100 watt under the 110 volt sistem until i met the electro man with the plan and proved me wrong so now i run two lamps on 240 and my bill is no different so YES, IS DEFENETLY A PLUS

I have a similar model (No backlit display). I don't get to use the clamp as often as I'd like (often times wires are sheathed with a neutral)

The voltage thing for me is a peeve because I often do new construction. If your voltage is that low with new wires, you have a problem (voltage drop of course).

Yes, that older wiring has been heated up so many times, it causes more resistance, hence the lower voltage...

Elite

Yes, 240v will save you money but not a lot. IMO, not enough to overly justify getting all 240v gung ho.

It has to do with watt loss. Also called power loss, copper loss and winding loss. There is also such a thing as iron loss which is also known as core loss.

Watt/Winding/Power/Copper loss comes into play with a resistive load. (baseboard heaters, water heaters, clothes dryer)

Iron/Core loss comes into play with an inductive load. (ballasts, motors, anything with a ferrous core)

It would probably help to know the difference between a resistive load and an inductive load but you guys can google it if you really want to know. If your even remotely interested in electricity, it would benefit you to know the difference between the two.

Iron loss is due to 2 things. Hysteresis and eddy currents.

Copper loss = Energy dissipated in the form of heat due to the resistance of the wire or element.

Hysteresis = Magnetic friction in the core.

Eddy Currents = Electric currents induced in the core.

This is why digital ballasts are INSANELY more efficient than Magnetic "Core&Coil" ballasts. I find it funny when 240v zealots are running all mag ballasts....

Actually, <whatever> loss is energy being dissipated in the form of wasted heat, thus not utilized by the source load (because it never gets there, ie - bleeds off as heat).

That's why resistive loads are remarkably inefficient. You use an element with an insanely high amount of resistance (tungsten filament in a light bulb) and when you apply current to it, the electrons have an extremely hard time moving through it so the high resistance material gets insanely hot (due to friction between electrons and tungsten). Then it starts to glow, thus providing light. Did you know that the temperature of a light bulb filament is the same temperature as the sun?

Math is an indisputable way to confirm Copper loss by way of Ohms Law.



P = I² x R

We'll use one 1000w ballast as an example. Lets just say that this ballast draws 8.3A @ 120v and 4.16A @ 240 (Ohms Law again).

We ran a dedicated #14 AWG circuit to feed this ballast. It's a multitap ballast, meaning it can run at 240 or 120. What should I use? Doesn't really matter but since we are talking about copper loss, lets figure it out. The distance from circuit breaker to receptacle is 78 feet. So that's 78' of 14/2 romex.

I go to Chapter 9 Table 8 in the NEC. I find out that 1000' of #14 CU has a resistance of 3.07 Ω. So that means our 78' has a resistance of 0.24 Ω

120v circuit:
(8.3 x 8.3) x 0.24 = 16.53 watts lossed

240v circuit:
(4.16 x 4.16) x 0.24 = 4.15 watts lossed

Holy crap! That's a lot right? Wrong.

Take the difference of the two to see what we are "missing out on" by running at 120v, which is 12.38 watts.

Savings = 12.38w x 12h x 11centsperhour / 1000 = 0.0163416

You save a penny and a half per day on a 12 hour bloom cycle billed @ 11cents pKWh by running @ 240v...
I'm gonna switch right now! :wink: Not.

Lets put it another way. If you really love wriglys Juicy Fruit gum and it costs 1.29 at your local supermarket, after running your light @ 240v for

947 HOURS

you can get a "free" pack of gum. Sweet!!!! Juicy fruit, is gonna move ya'. It's a song, sing it loud, the taste is gonna move ya!

BTW, that's a bad Ohms Law wheel. Didn't notice til just now. "V" should be "E". As in Electromotive Force

Thanks for that VERY in depth/informative post, as always!!

LOL, nothing left to add...

Elite

I will add that this is one reason why commercial/industrial lighting runs @ 277v... Picture the mother of all warehouses with massive amounts of hid lighting.

O.k.... Now that's no pack of gum were talking about now. For you guys to be even remotely concerned, you need to have a MASSIVE grow op in progress. But if your growing that much shit then your rolling in the cash so who really cares about a 5 dollar a month savings with 240v....

Your main, and only, concern with 240 vs 120 is to reduce the amperage draw and voltage drop that comes with running @ 240v, not to reduce Copper loss...

madpenguin said:

I will add that this is one reason why commercial/industrial lighting runs @ 277v...

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Or why they use 3 phase to begin with...

madpenguin said:

O.k.... Now that's no pack of gum were talking about now. For you guys to be even remotely concerned, you need to have a MASSIVE grow op in progress. But if your growing that much shit then your rolling in the cash so who really cares about a 5 dollar a month savings with 240v....

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LOL, very true!!

Elite

RESPECT MADPENGUIN.
PLEASE EXPLANE WHY MY BILL DID NOT CHANGE BY SWITCHIN FROM ONE 1000 WATT ON 120V TO TWO 1OOO WATT LAMPS ON 240?


A BLESS TO HAVE YOU AMONG US.

Would using a 12 gauge or even 10 gauge wire give you more savings because of less resistance?

Spot on. I was going to mention this situation tho because people actually do this thinking it will save them money. People have wired their entire houses in #12 and #10 for this reason alone.

What they don't realize is, it would take you years upon years (decades even for a whole house wire) just to break even on the increased cost of wiring.

The Math is all there on my previous post. I'll give you guys some more resistance values and you can play around with it. Once you calculate the cost savings between a couple different wire gauges, compare that against the cost increase in larger wire. Doesn't matter if it's just for one branch circuit, you'll be waiting a couple years just to break even before you can begin to "save" money.

Go to Lowes or Home Depot and record the cost differences between #14, #12 and #10, do the math, and you'll see.

1000' #14 = 3.07Ω
1000' #12 = 1.93Ω
1000' #10 = 1.21Ω
1000' #8 = 0.764Ω
1000' #6 = 0.491Ω

Logically, the thicker the wire the less resistance it has. Voltage drop is also greatly reduced with larger wire (as long as your at the same amperage between wires ofcourse).

Silver is about the only other metal that has a lower resistance than copper. Believe it or not, you can buy silver wire. I have some just because I'm a metal/science freak. It ain't cheap. Gold wire, platinum wire... You can find it online.

To be a hypocrite, I'll admit I've done the same thing. I installed some baseboard heaters in my finished attic. Had no heat runs going up there so was unusable in the winter. Not unless I use it to store meat.

My total amperage was just under 16A. Typically, you'd use #12 AWG. I already had quite a bit of #10 left over from a previous job that I slipped into the back of my truck without telling anyone. I used it. 16A @ about 130' from breaker to thermostat. Do the math or not. Just by looking at the resistance values of #12 and #10, I know I'm almost halving my watt loss. The wire was free, otherwise I wouldn't have considered it.

240v can be better depends on the ballast. i tried 120 and 240 on my C&C 1000watter. I figured out to be round 50 watts saved. 10gauge wire on both. Been too lazy to check the difference on my 600watt digital.