Local Disconect and Design Question

Status
Not open for further replies.
B

BZ2005

Member
Let me run this by you Guys.

A 30 Hp Motor (480VAC Nameplate FLA 35A) run off a 40 HP VFD (Continuous 30HP max 59A out) with the motor about 3 feet above and 3 feet behind the Control Panel. (clearly visible/ line of sight from the control panel).

Control System / Wiring all internal to Panel.
A 100A circuit breaker feeding a Power Distribution Block to a set of 80 Fuses (59a * 1.25) for the VFD and also feeding a set of fuses for a 5KVA 480/120 VAC 1PH transformer (to small controller).

Would using a through-the-door disconnect switch or maybe even a cable operated disconnect switch (lockable) on the 100a breaker, be a NEC legal move?
 
Jraef

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Line of sight, no brainer. Yes.

If the machine is needing NFPA79 compliance, be aware that many thru-door rotary disconnects no longer qualify. NFPA79 dictates that when the door is open, the disconnect must now be operable without a tool, AND it must be lockable in the off position. Some mfrs have updated their products and offer an "NFPA79 Kit" that consists of an internal handle and hasp, but the cheaper ones do not and they don't tell anyone about this, because not all control panels need to meet NFPA79. All flange-mount disconnects inherently meet this standard however.
 
B

BZ2005

Member
Jreaf
I know it's was kind of a dumb question. But for some reason i an not good a convincing other people.

Thanks for the head up on NFPA 79 I was not aware.
Square D does make an accessory kit for style I plan on using.
 
Status
Not open for further replies.
Top