unbalanced loads

[Shockedby277v]

If your loads are unbalanced, does it cost more on your electric bill??

 

[don_resqcapt19]

.....no...

 

[charlie tuna]

unbalanced loads do cause your electrical bill to increase but only slightly. anything that causes the production of heat in your electrcal system, when exceeding it's designed functions, uses un-necessary power. it was documented that a bad connection on a twenty amp circuit can cost $200. a year in electrical energy consumption!! a balanced system would minimize the maximum current drawn in it's conductors and reduce the total heat generated by that system.

 

[LarryFine]

It seems to me that an unintentional voltage drop in a circuit would decrease the current a bit. If you consider that someone will need to keep the power on a bit longer to compensate, to get the same work done, then I could see the more-power-purchased-for-the-same-power-used theory making sense.

 

[winnie]

I seem to recall a thread that mentioned that at least some electric meters do not properly measure the line to neutral voltage _separately_ for each supply leg, but instead measure line to line voltage only and then assume balance. The thread mentioned that in this case, unbalanced loading would cause metering errors.

-Jon

 

[LarryFine]

I seem to recall a thread that mentioned that at least some electric meters do not properly measure the line to neutral voltage _separately_ for each supply leg, but instead measure line to line voltage only and then assume balance.

That makes sense since the typical resdential meter has no neutral contact. Load current balance is irrelevant. The meter measures the voltage to it and the current through it. It's up to us to minimize unusable power waste beyond the meter.

 

[iwire]

That makes sense since the typical resdential meter has no neutral contact. Load current balance is irrelevant. The meter measures the voltage to it and the current through it.

I agree, and this is why single phase meters used on 208Y/120 Systems do have a neutral connection.

 

[rattus]

Well, maybe:

Well, maybe:

If your loads are unbalanced, does it cost more on your electric bill??

For 120V 2-wire branch circuits, the imbalance does not affect the power wasted in the neutrals. For a balanced multiwire branch circuit, the power in the common neutral is zero. This amounts to a 50% reduction in power lost in the branch circuit.

 

[robbietan]

unbalanced loads will make you pay more for maintenance of your three phase motors, should the unbalance go beyond 2.5%