How to lock out remotely controlled circuit breaker in OFF position? 2

[thinker]

We received VFD with power entry cabinet that has ABB EMAX circuit breaker (5000A, 1000V). This is a fixed mounted MCB with motorized control and push buttons ON and OFF on the cabinet door. We feel that the MFG completely missed the OSHA requirement that the main disconnect device must have provisions to be locked out in OFF position. Is there any practical advice how to address this problem? Our supplier seems not to have any idea about that...

 

[ShooterBooter]

Isn't the CB withdrawable?

-SB

 

[thinker]

No, it is not (see the second sentence of OP).

 

[ShooterBooter]

Sorry, missed that (on My Iphone, small screen...)
You can't disconnect aux power to the CB and thus making it inpossible to operate?

-SB

 

[thinker]

I, probably, could do that; also I could install individual cover with padlock on "MCB ON" push button. but, per OSHA, this would not replace safety of locking out the disconnect itself in OFF position. I begin thinking that only rack-out (or withdrawable) version of EMAX would comply.

 

[ScottyUK]

ABB provide an accessory which locks the 'trip' button in the pressed state, thus ensuring that the breaker trips through even if someone manages to perform a close operation. The mechanical trip overrides any close command. Google ABB part number 1SDC200158F0001 or find it in the catalogue using search within the PDF - if you find a hi-res photo of the item you'll see a protrusion on the back of the cover for the 'trip' button which holds it in when the cover is locked in position.

 

[thinker]

Thank you, Scotty, this is very interesting! I did see this accessory, but it was described just as a cover that blocks access to any of local push buttons when padlocked. Please refer to the ABB source of the info you provided: that special protrusion on the back of the cover that keeps the OFF button depressed thus ignoring any external remote command. I could not find this detail in ABB literature. Is this a practical experience, or a well hidden feature of this simple plastic cover? I would need to present some proof to safety officials.

 

[ScottyUK]

This catalogue lists it on page 11 (13th page of the PDF) as an accessory for a T8 series MCCB, but it is exactly the same accessory for the E-Max ACBs and you can verify this from the part number. The image in the T8 catalogue is a bit clearer than in the E-Max catalogue I have and if you zoom right in you can see that the moulding for the right cover is subtly different to that for the left cover: there are darker lines visible on the front of the right cover where the moulded protrusion is located, and you can just about make out the triangular projection behind the cover which holds the trip button in the operated state. The left cover is simply a flat cover.

A few years ago I went through the same process that you currently are. ABB's documentation isn't exactly helpful.

 

[thinker]

Thanks a lot, Scotty, I was really lucky to get such good advice.

 

[ScottyUK]

No problem, glad it was of some help.