Arc flash label required on control station?

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Glenn M

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I have a question about whether the NEC now requires arc flash labels on pushbutton enclosures:

Per NEC 110.16, industrial control panels are required to have field marking to “warn of potential electric arc flash hazards.”

110.16 Flash Protection.
Electrical equipment, such as ... industrial control panels, ... that are in other than dwelling occupancies, and are likely to require examination, adjustment, servicing, or maintenance while energized shall be field marked to warn qualified persons of potential electric arc flash hazards. The marking shall be located so as to be clearly visible to qualified persons before examination, adjustment, servicing, or maintenance of the equipment.

Per NEC 409.2, the second definition of an industrial panel is an assembly of pushbuttons, pilot lights, selector switches…

409.2 Definitions.
Control Circuit. The circuit of a control apparatus or system that carries the electric signals directing the performance of the controller but does not carry the main power current.
Industrial Control Panel. An assembly of two or more components consisting of one of the following:
(1) Power circuit components only, such as motor controllers, overload relays, fused disconnect switches, and circuit breakers
(2) Control circuit components only, such as pushbuttons, pilot lights, selector switches, timers, switches, control relays
(3) A combination of power and control circuit components

Does this mean every pushbutton station whose components are operating at 50 volts or more is now required to have an arc flash label?

Glenn M
 
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Pushbutton Enclosures

Pushbutton Enclosures

I believe that the requirement for arc flash labels on panels does not include low voltage externally mounted pushbuttons enclosures. At 50 volts there is insufficient capacity to sustain an arc flash.
 
Oh the wonders of unintended consequences. The Proposal for the current wording was part of a series to “clarify” that some Industrial Control Panels (ICP) consist only of control components. They are still ICPs but do not require short-circuit markings per Section 409.110 (3).

It definitely appears that the current wording implies something like a push-button/pilot light assembly meets the current (NEC) definition of an ICP. Welcome to Charlie’s rule.
 
Not so quick Rich; NFPA70E says 50 volts or more you must wear PPE. It is very common to have 120volts on push button panels so yes PPE is required unless less than 50v. I want to agree that Arc flash labeling is not required But yet... a push button panel does fall under the definition of "Industrial control panel" Good question. :-?
 
I know that this is not a regulation, but according to 70E(2009) 130.3 Exception 1: An arc flash hazard analysis is not required when all of the following conditions are met:
1. the circuit is rated at 240 volts or less
2. the circuit is supplied by one transformer
3. the transformer supplying the circuit is rated less than 125 kVA.

Hope this helps
 
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