Code #110.4 Question

[Finchkramer]

We current are designing a building that has a nominal voltage of 240 with an air conditioner rated for 230V going into it. Is this a violation of code #110.4 or is it ok, because its within 10% of the nominal voltage.

Thank You for Your Time,

 

[iwire]

We current are designing a building that has a nominal voltage of 240 with an air conditioner rated for 230V going into it. Is this a violation of code #110.4 or is it ok, because its within 10% of the nominal voltage.

Thank You for Your Time,

A unit listed for 230 is designed to be supplied from a 240 volt source.

The same way 460 volt labeled equipment is designed for a 480 volt supply.

 

[charlie b]

I have never seen this written down in any official publication, but I believe the reason is that the motor manufacturers are expecting there to be some voltage drop between our 480 volt source and their 460 volt motor.

 

[jim dungar]

I have never seen this written down in any official publication, but I believe the reason is that the motor manufacturers are expecting there to be some voltage drop between our 480 volt source and their 460 volt motor.

There is some information in the IEEE Std 141-1993 (Red Book) section 3.2.3 Development of the voltage tolerance limits for ANSI C84.1-1989
"The voltage tolerance limits in ANSI C84.1-1989 are based on NEMA MG 1-1993, which established the voltage tolerance limits of the standard induction motor at ?10% of nameplate ratings of 230 V and 460 V. Since motors represent the major component of utilization equipment, they were given primary consideration in the establishment of the voltage standard."

 

[kwired]

I have never seen this written down in any official publication, but I believe the reason is that the motor manufacturers are expecting there to be some voltage drop between our 480 volt source and their 460 volt motor.

plus they have to pick a voltage so that they can determine amps, speed, power factor, efficiency, or other items that maybe on the plate. All those values listed on the plate are assuming full load at the voltage marked, change that voltage a little bit and other items also change a little bit, assuming the load remains constant.