Where is the best place to reverse the leads for a motor?

[hillbilly1]

most VFDs have a parameter you can set to do this with no wiring changes required at all. much easier.

I don't see how 210.5 (C) 1 could possibly apply downstream of a VFD anyway. The VFD is effectively an SDS at that point.

True, but most electricians don’t like playing with the settings.

 

[garbo]

Where is the most common place to reverse the leads for a motor? In the pecker head? In the bucket? In the disconnect? Any reasons why one place is better than the other? Also is it common to write YOB or BOY or whatever, where you changed it? Thank you for your help.

Almost always easier to reverse three phase leads at the starter. If you have motor on a VFD without bypass you can do it quickly by changing one parameter that I forget what they call it. On Danfoss drives they have a small halve circle with a pointer on one if the ends usually at top right of LCB ( Local control panel = fancy name for the little touch screen ) From the factory the arrow usually points to a clock wise rotation. Changing the input on VFD'S will never change rotation due to the drive input goes thru full wave rectifier that in turns feeds IGBT'S. Found that out the hard way 45 years ago.

 

[ptonsparky]

We usually changed the load side. Knew we didn't need to but it was SOP. They were also small. Largest would have been a 200. Not sure if we even needed to change it.

 

[don_resqcapt19]

What the heck was the rational reasoning for 210.5?

There was no rational for the 2017 change that removed the words "except for branch circuits that supply only motor loads, which are covered in Article 430" from the scope of Article 210.

 

[GoldDigger]

It doesn’t prevent you from doing it, you just need to mark them.

The typical marking system is by color, with the standard used posted at various places within the system. But if rotation reversal is necessary anywhere up stream of the motor you can either avoid color identification (all black?) and use some other form of identification. Or simply add supplementary identification to the wires to override the default of color coding. Be sure to label both at the crossover point and at the peckerhead.

 

[don_resqcapt19]

The typical marking system is by color, with the standard used posted at various places within the system. But if rotation reversal is necessary anywhere up stream of the motor you can either avoid color identification (all black?) and use some other form of identification. Or simply add supplementary identification to the wires to override the default of color coding. Be sure to label both at the crossover point and at the peckerhead.

There is no way that most will ever comply with this rule and there was no technical justification provided for the scope change of Article 210 in the 2017 code.
Most will continue to make the change as the starter and not re-identify the conductors at the motor junction box.

The rule requiring identification as to phase was never intended to apply to 3 phase line to line circuits. When it was originally put into the code, it only applied to multiwire circuits and was found in 210.4. It was intended to prevent the overloading of the neutral conductor of a multiwire circuit.
In the 2005 code, it was moved to 210.5 but only required that the conductors be identified by system and not by phase. That did not accomplish the original intent or preventing the overloading of the neutral of a mulitwire circuit, so in the 2008 code, the requirement was expanded to require
identification by both phase and system where there is more than one voltage system in the building.

There have been PIs to say that the identification by phase is not required where the circuit only supplies line to line three phase loads, but they have been rejected by the CMP, mostly because the CMP does not really understand what the 2017 scope change means for motor circuits.