Unbalanced electrical load

[orezok]

I've been a licensed general contractor since 1979 and I've asked several of my electrical subs this question, but nobody seems to know the answer.

On a typical electrical main panel, the loads between the legs are usually "balanced". That is the labeled amperage of the breakers on leg A is roughly equal to the amperage on leg B (ignoring 2 pole breakers).

But what if the leg A breakers handle appliances in the kitchen, the furnace and other large draw items, but the breakers on leg B handle lesser (or no) draw items such as lighting or "unused" circuits.

The question is, does the electric meter measure the greater amperage draw of the 2 legs or an average of the 2?

 

[LD1]

I could be wrong but I thought they took the sum of the two legs based on 120v to ground. IE, 50 amps on one leg is 6kwh and 25A on the other is 3kwh so total would be 9kwh.

But if they are indeed averaged, there would be no difference. Because there are only two legs. so the average of 25 and 50 would be 37.5a on 240v would still be 9kwh.

But if they are indeed taking the larger leg, 50a, 6kwh, and doubling that.....that would be a ripoff @ 12kwh:confused2:

Either way, I'm not an electricial and I dont know. Just wanted to share what I "thought", and also subscribe because I might learn something.

If they do take the larger leg, it wouldnt take much to re-balance based on conditions (season, peoples preferences, etc) and save some $$$. But I dont see it being the case. I think you actually pay for what you use.

 

[hr3]

The simple answer is,,
The electric company charges you for watt-hours, not volts. To figure volts you use the fomula Volts x Amps = Watts. A device that runs on 240V will use half as many amps as an identical device that runs at 120V, so the wattage will be the same -- and so will the cost.
The kinds of appliances that use 240V tend to be energy hogs, like air conditioners and electric clothes dryers, so running those appliances will cost you. It's not because 240V costs more, it's because you're running energy-gobbling appliances.
Next will come several not so simple answers,,:laughing:

 

[orezok]

The simple answer is,,
The electric company charges you for watt-hours, not volts. To figure volts you use the fomula Volts x Amps = Watts. A device that runs on 240V will use half as many amps as an identical device that runs at 120V, so the wattage will be the same -- and so will the cost.
The kinds of appliances that use 240V tend to be energy hogs, like air conditioners and electric clothes dryers, so running those appliances will cost you. It's not because 240V costs more, it's because you're running energy-gobbling appliances.
Next will come several not so simple answers,,:laughing:

Yes that's a simple answer, but it doesn't address the question.

 

[ducks13]

It measure each leg separately and adds them together.

 

[grsthegreat]

There was another discussion here about that same thing, and even though i am an electrician i was always told that it only measured the highest leg.

I found out that that was wrong (even though i still get that told to me by power company employees and at code update classes.....i think everyone is unsure)....it measures both loads... so it doesnt matter if its balanced

We still try to balance our panels out the best we can, but its impossible to know what someone may plug in later on. The 240 loads are automatically balanced so they dont count.

Back in the good old days, i could unplug my meter and put it on upside down and spin the meter backwards well welding...cause i was a spoiled little brat those days.

The new electronic meters prevent that....too bad (cause im still a spoiled little brat at times).:mur::mur:

 

[crazyal]

There's a much bigger reason why you need to balance your load. Anyone ever wonder why the two 'hot' wires feeding the main breaker box are larger than the one neutral wire?

 

[grsthegreat]

There's a much bigger reason why you need to balance your load. Anyone ever wonder why the two 'hot' wires feeding the main breaker box are larger than the one neutral wire?

Cause alot of the larger loads in residential applications are 240 and dont require a neutral. In commercial applications the neutral and the hots are the same size.

 

[5030]

I'm so glad I always hire a certified electrician to hook things up.

I've considered unplugging the meter and jumping the lugs 'cause I'm cheap.

Just considered, I'd probably electrocute myself.

 

[BobRip]

They measure and charge for watt hours. Balancing is good as mentioned above, but it does not affect your bill.