I have an issue on a current design that I'm having trouble understanding the code requirements. I'll set this up as briefly as I can - sometime I'm wordy.
We have four movable vertical lift bridge spans. Each span has a drive motor coupled to machinery at each end to raise the spans. Each drive motor has a local disconnect. Each bridge span has a control cabinet containing two circuit breakers, two motor starters, control relays, and pushbuttons on the cover. There is a 480V feed to each control cabinet from a switchboard. A 120V control power feed is also provided from a panelboard for each control cabinet. The four control cabinets, switchboard, and panelboard are located in an electrical room off the bridge spans.
The panel builder has proposed not using a disconnect at the control cabinets but instead provide markings of where the power feed and control power disconnects are located. Because the switchboard and panelboard are in the same room I believe this is code compliant. If so, do the circuit breakers at the switchboard and panelboard need to be supplied as LOTO breakers?
Another questions is whether each circuit breaker at the control panels feeding a motor starter needs a through the door disconnect. It seems 430.102 (A) would require one. You cannot see the motors from the control room so I would think exception No. 2 does not apply.
I'm looking to see if there is agreement on how I'm looking at this. I know the panel builder is a UL listed shop but they did not bid the through the door disconnects.
I appreciate any insight.
Regards,
whiggins
We have four movable vertical lift bridge spans. Each span has a drive motor coupled to machinery at each end to raise the spans. Each drive motor has a local disconnect. Each bridge span has a control cabinet containing two circuit breakers, two motor starters, control relays, and pushbuttons on the cover. There is a 480V feed to each control cabinet from a switchboard. A 120V control power feed is also provided from a panelboard for each control cabinet. The four control cabinets, switchboard, and panelboard are located in an electrical room off the bridge spans.
The panel builder has proposed not using a disconnect at the control cabinets but instead provide markings of where the power feed and control power disconnects are located. Because the switchboard and panelboard are in the same room I believe this is code compliant. If so, do the circuit breakers at the switchboard and panelboard need to be supplied as LOTO breakers?
Another questions is whether each circuit breaker at the control panels feeding a motor starter needs a through the door disconnect. It seems 430.102 (A) would require one. You cannot see the motors from the control room so I would think exception No. 2 does not apply.
I'm looking to see if there is agreement on how I'm looking at this. I know the panel builder is a UL listed shop but they did not bid the through the door disconnects.
I appreciate any insight.
Regards,
whiggins