rwilsond
Member
- Location
- Orange County, CA 19 years of exp.
There's gotta be someone out there that can tackle this!
THE SITUATION:
A particular 480V Industrial Control Panel in a "Supervised Industrial Installation" is fed from a large (say 2000 kVA) transformer, without any type of OCPD on the transformer's secondary side, and without a Main CB inside the panel. Instead, the 15-foot long "tapped" supply conductors terminate onto two separate CB's inside the control panel.
THE CODE REQUIREMENTS:
New Article 409 for the 2005 NEC requires that either a single OCPD be located ahead of an Industrial Control Panel, or a Main CB (i.e., ONE CB) be located within the Industrial Control Panel. But 409.21 states that this protection shall be provided in accordance with 240.21 Parts I, II, and IX.
THE QUESTION:
Can the reference above (to 240.21) be interpreted to mean that the Industrial Control Panel is allowed to NOT have a Main CB (Main implies ONE), nor an upstream feeder CB by satisfying one of the so-called "tap-rules" of 240.21?
THE SITUATION:
A particular 480V Industrial Control Panel in a "Supervised Industrial Installation" is fed from a large (say 2000 kVA) transformer, without any type of OCPD on the transformer's secondary side, and without a Main CB inside the panel. Instead, the 15-foot long "tapped" supply conductors terminate onto two separate CB's inside the control panel.
THE CODE REQUIREMENTS:
New Article 409 for the 2005 NEC requires that either a single OCPD be located ahead of an Industrial Control Panel, or a Main CB (i.e., ONE CB) be located within the Industrial Control Panel. But 409.21 states that this protection shall be provided in accordance with 240.21 Parts I, II, and IX.
THE QUESTION:
Can the reference above (to 240.21) be interpreted to mean that the Industrial Control Panel is allowed to NOT have a Main CB (Main implies ONE), nor an upstream feeder CB by satisfying one of the so-called "tap-rules" of 240.21?