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Chief Rick

Any electricians in the saloon?

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Was told today that when running circuits to a power distribution panel the two sides of the panel should have evenly distributed amp draws.

 

Otherwise, a panel with uneven distribution would use more electricity than a panel with equal distribution.

 

Can any one verify or refute this claim?

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Yep its true. Should be balanced as close as possible to keep the usage from both sides at the same time as close as possible.

kR

Edited by Kid Rich

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On all the pannels that I have worked on if you go down one collum the buss will alternate between them. So you should go all the way down one colum before you move to the next one.

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On all the pannels that I have worked on if you go down one collum the buss will alternate between them. So you should go all the way down one colum before you move to the next one.

they do that so you can get your 220s, range, water pump, dryer, A/C.

 

As to which leg draws more current, that's a bit random.

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If you look at an empty UNPOWERED breaker panel you will see that every other breaker in a vertical row are on the same leg of the power feed.

It is common practice to balance the printed current draw on each leg so that they are approximately the same.

In actual practice the legs will always be unbalanced as you may not be using some circuits while other circuits are at near maximum.

 

A panel with uneven current draw is the norm and you will not use more or less electricity. The meter on the outside of your home/business measures the current draw on each leg/phase separately and will read the same if you are using 50 amps on phase A only or if you are using 25 amps on phase A and 25 amps on phase B. Your bill will be exactly the same.

Edited by Ace_of_Hearts

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If you look at an empty UNPOWERED breaker panel you will see that every other breaker in a vertical row are on the same leg of the power feed.

It is common practice to balance the printed current draw on each leg so that they are approximately the same.

In actual practice the legs will always be unbalanced as you may not be using some circuits while other circuits are at near maximum.

 

A panel with uneven current draw is the norm and you will not use more or less electricity. The meter on the outside of your home/business measures the current draw on each leg/phase separately and will read the same if you are using 50 amps on phase A only or if you are using 25 amps on phase A and 25 amps on phase B. Your bill will be exactly the same.

+1

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When drawing power form the utility grid, balancing is only required with large 3 phase loads. Balancing the voltage supplied to each leg of a 3 phase motor will make it run more efficiently which means it will use less total power.

 

99.99% of residential service in the US does not have 3 phase power. Only ones I have ever seen were large farms and the 3 phase was to support the farm and not the house.

 

Your meter reads actual usage as a sum total of the power drawn. The meter doesn't care if one leg draws more than another.

 

If you are running a 3 phase generator there is benefit to having reasonably balanced loading but that is a completely different situation.

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Power consumed is the same irregardless which leg of the 240v 3 wire service it comes from. And as has been stated the electric meter used by power companies, including the one I work for, will aggregate the power running through the meter regardless of which leg it comes from. This is for single phase service.

 

As has also been stated, this would be the same for a three phase service as well. And yes, three phase devices, particularly motors and control circuits are a little more efficient when the voltages are the same all all three legs but they will normally run well unless there is an extreme difference between phases. It is possible to have one leg so heavily loaded that the voltage on the leg may be too low and a motor controller would see it as a low voltage problem and either trip out or fail to actually start a motor.

 

Kajun

Edited by Krazy Kajun

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Was told today that when running circuits to a power distribution panel the two sides of the panel should have evenly distributed amp draws.

 

Otherwise, a panel with uneven distribution would use more electricity than a panel with equal distribution.

 

Can any one verify or refute this claim?

Are you asking about commercial 3 phase, or single phase residential?

Have to know that before correct answer can be given.

OLG

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Are you asking about commercial 3 phase, or single phase residential?

Have to know that before correct answer can be given.

OLG

Single phase residential.

 

It didn't make sense to me but hey - I'm no electrician.

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Chief Rick,

 

The reason that they state try to balance the load on a residental panel is the Neutral will carry the unbalanced load, so if you have 60 amps on one phase and 30 amps on the other the neutral is would have a load of 30 amps. It gets much worse with three phase. Which is why the neutral must be the same wire size as the feeder wires. I can go in to more detail if you wish but it makes my brain hurt also.

 

Old Top

(electrician for about 40 yrs)

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