Local disconnect for harmonic filter

[mshields]

So I've got this 350A (feederf) AHU. Is has a disconnect but ahead of the disconnect is an In-Line Harmonic filter (by Mirus) and the contractor wants to know if there should be a disconnect ahead of it.

What would be the letter of the law here. Does the breaker that feeds it have to have permanent provisions to be locked out. Do I even need that?

There are 4 of these things and I'd rather not have to give green light to 4 400A disconnect switches.

 

[Jraef]

The harmonic filters are wired in AHEAD of the disconnect for the VFD? That's a mistake. How are you going to work on the filter if you can't turn off the power to it?

The right way to have done it was to connect the filter on the LOAD side of the disconnect. If that's not possible, then yes, each one needs its own disconnect. It's just like having a transformer ahead of it (well, a Mirus IS a transformer...).