line voltage tolerances
line voltage tolerances
(OP)
Can someone tell me where to find a standard on the standard deviation of line voltage in North American systems. Is there a given tolerance for the utility that they must meet when they supply each different voltage. For instance, if the line voltage is 277/480 volt how low can the 277 be and how high can it be. Question #2 would be is this the responsibility of the electrical engineer when doing the design? Question #3 would be is there a standard for that.
Thanks.
Thanks.






RE: line voltage tolerances
http://utilities.dteenergy.com/infoZone/programsInfo/vo...
RE: line voltage tolerances
RE: line voltage tolerances
A default answer is ANSI Std C84.1-1995, American National Standard for Electric Power Systems and Equipment – Voltage Ratings (60 Hertz). Resolution is often spelled out in utilities’-commission agreements, or the product of contractual verbiage in a purchase order. The lower limit for 277V systems is usually 254 volts, but C84.1 contains a number of qualifying conditions.
RE: line voltage tolerances
The standards require the customers to maintain a certain degree of load balance on their systems.
God bless!
RE: line voltage tolerances
The NEC recommends for best efficiency that voltage drop of branch circuits not exceed 3% and there should be no more than 5% total drop from the point of service to the loads. This is a reasonable guideline.
RE: line voltage tolerances
However, the Utility is probably used to complaints about voltage drops approximately -10% to +10%; more often -10%.
RE: line voltage tolerances
This is a great site and I will keep in touch in case I can answer a question for someone in the future.
Thanks again!