Is a disconnect after harmonic filter required?
Is a disconnect after harmonic filter required?
(OP)
I am working on a electrical chiller replacement job. It involves replacing an constant speed chiller with a VFD chiller. I planned on using the existing CB to feed a new harmonic filter physically inplace of the old motor starter(adjacent to existing powerpanel) and then connecting the filter to the unit mounted VFD w/CB.
An engineer says this is a violation of the NEC 25 FT Tap rule because the cables are 30 FT and a disconnect is required after the filter.
The filter consists of a two series reactors with a capacitor bank tapped after the first reactor. There is no electrical isolation, like a transformer. I am considering this filter integral to the dedicated branch circuit and not a tap rule application, therefore, no disconnect is required.
All the cabling is sized for full load. Which view correct??? Help is greatly appreciated.
An engineer says this is a violation of the NEC 25 FT Tap rule because the cables are 30 FT and a disconnect is required after the filter.
The filter consists of a two series reactors with a capacitor bank tapped after the first reactor. There is no electrical isolation, like a transformer. I am considering this filter integral to the dedicated branch circuit and not a tap rule application, therefore, no disconnect is required.
All the cabling is sized for full load. Which view correct??? Help is greatly appreciated.





RE: Is a disconnect after harmonic filter required?
It is not a seperately derived source so secondary side disconnect is not required, as it would be in case of a transformer.
RE: Is a disconnect after harmonic filter required?
RE: Is a disconnect after harmonic filter required?
Don
RE: Is a disconnect after harmonic filter required?
You are correct in interpretation of the Code.
I figured that was the intent of "other" engineer that OP referred to,as a tap rule was mentioned. Conductors need to be protected at the origin and a separately derived source (tranformer) would be a new origin but not a reactor.