Current Unbalance Standard
Current Unbalance Standard
(OP)
Is there any standard (IEEE, NEC, ANSI and others) that have an standard for current unbalance not to exceed a certan % on a main service.
When was the last time you drove down the highway without seeing a commercial truck hauling goods?
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Current Unbalance Standard
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RE: Current Unbalance Standard
If you have an undersized service supply neutral or load neutral, then the unbalance load current must not be exceded the the size of the rating of the neutral wire and neutral bus. That is why it is a good idea to use 100 percent rated neutral buses and 100 percent ground buses and cable, because you don't know when these loads will be extremely unloaded. Also check the utility ground wire they usually run undersized ground service cables.
Also,I found that with small generators the voltage on the unloaded size will rise and the loaded side will drop with extreme load unbalances, which is bad.
Check with your utility co and source transformer mfg., they may have some unbalance current requirements.
RE: Current Unbalance Standard
There’s probably not much in US consensus standards on current imbalance. There is a curve in ANSI C84.1-1995 that compares motor-horsepower derating to voltage imbalance. Current imbalance is more likely limited as a condition of service.
The [customer] must balance his demand load as nearly as practicable between the two sides of a three-wire single-phase service and between all phases of a three-phase service. The difference in amperes between any two phases at the customer's peak load should not be greater than 10 percent or 50 amperes (at the service delivery voltage), whichever is greater… It will be the responsibility of the customer to keep his demand load balanced within these limits.
RE: Current Unbalance Standard
RE: Current Unbalance Standard
Jerry123, could you please elaborate on the meaning of "The ANSI sounds better with the 10%"?
RE: Current Unbalance Standard
The comment I made about ANSI and 10%. I only said it because the current unbalance parameter on the metering equipment is set a at 5%. In some cases this value would make sence and other it would not.
RE: Current Unbalance Standard
RE: Current Unbalance Standard
Bung
Life is non-linear...
RE: Current Unbalance Standard
The (italicized) verbiage in my 30-Jul entry is not from C84.1—it is an example of service conditions described by an electric utility. C84.1 discusses voltage imbalance.
RE: Current Unbalance Standard
RE: Current Unbalance Standard