Motor starter coil voltage vs. motor voltage
Motor starter coil voltage vs. motor voltage
(OP)
Can someone tell me where in the NEC it says that you must use a starter that has the same coil voltage as the motor it will be starting? My salesman told me today that he could no longer get me 120 volt coil, 480 volt starters as they are a violation of the NEC. I could be mistaken, but I read it as saying that as long as the conductor insulation used for the coil is rated to 600 volts like the conductors used for the motor that you would not be in violation. He is telling me that I must use a 480 volt coil to match the 480 volt motor leads. I am using a seperate 120 volt source for the control circuit coming off a PLC.





RE: Motor starter coil voltage vs. motor voltage
RE: Motor starter coil voltage vs. motor voltage
480 V control circuits are still legal, but probably not for much longer due to arc-flash issues. 120V ac control voltage is by far the most common in the US and has been for about 50 years.
Not sure what he thought he was talking about. How many beers did he have for lunch?
RE: Motor starter coil voltage vs. motor voltage
I would guess he screwed up and accidentally ordered a bunch of starters with 480V coils, now he is stuck with them because nobody uses them any more, so he is concocting a story to try and pawn them off on you!
By the way, where did you see anything that even mentioned the wire insulation rating needing to be the same?
Like rbulsara said, find another supplier.
JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
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RE: Motor starter coil voltage vs. motor voltage
RE: Motor starter coil voltage vs. motor voltage
respectfully
RE: Motor starter coil voltage vs. motor voltage
RE: Motor starter coil voltage vs. motor voltage
RE: Motor starter coil voltage vs. motor voltage
RE: Motor starter coil voltage vs. motor voltage
RE: Motor starter coil voltage vs. motor voltage
By the way, you do realize don't you that Article 725 is only referring to special installatons don't you? That is not intended for normal motor control circuits, in fact, the section you refer to is specific to Class I installations in emergency equipment which are under 30V behind a limited energy power source. I don't see the connection to motor starters.
JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> FAQ731-376
RE: Motor starter coil voltage vs. motor voltage
RE: Motor starter coil voltage vs. motor voltage
RE: Motor starter coil voltage vs. motor voltage
RE: Motor starter coil voltage vs. motor voltage
http://www.mikeholt.com/code_forum/index.php
JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> FAQ731-376
RE: Motor starter coil voltage vs. motor voltage
In a 480 V MCC or motor starter, all field wiring must be rated for 600 V since the power circuit occupies the same enclosure.
RE: Motor starter coil voltage vs. motor voltage
RE: Motor starter coil voltage vs. motor voltage
what dpc says is not what you are saying.
The origninal question asks if the coil has to match line voltage? The answer is no. Do the conductor insulation has to match that of the highest voltage present in a box, probably yes, but not always.
What voltage control coil would you use in a 13800kV breaker? What voltage insulation the coil condutor will have? Do not misinterprete the Code.
RE: Motor starter coil voltage vs. motor voltage
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Motor starter coil voltage vs. motor voltage
300.1 Scope.
(A) All Wiring Installations. This article covers wiring
methods for all wiring installations unless modified by
other articles.
(B) Integral Parts of Equipment. The provisions of this
article are not intended to apply to the conductors that form
an integral part of equipment, such as motors, controllers,
motor control centers, or factory assembled control equipment
or listed utilization equipment.
JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> FAQ731-376