Multiple Energy Source labeling

[duhhuh]

Often times, an MCC, PLC, Control Cabinets have control circuits (120v and less) with power being derived from other sources. The equipment is usually labeled something like: "Warning - One or More Live Circuits. This Equipment does not disconnect power to control or instrument circuits whose source is derived elsewhere. Please remove all sources of power before servicing."


Often used as a reference is 430.113. However, this is not specifically clear, nor is it clearly laid out in 725; 100 (definition for Labeled & Listed); 110.21 or 110.22.

thanks

 

[petersonra]

Often times, an MCC, PLC, Control Cabinets have control circuits (120v and less) with power being derived from other sources. The equipment is usually labeled something like: "Warning - One or More Live Circuits. This Equipment does not disconnect power to control or instrument circuits whose source is derived elsewhere. Please remove all sources of power before servicing."


Often used as a reference is 430.113. However, this is not specifically clear, nor is it clearly laid out in 725; 100 (definition for Labeled & Listed); 110.21 or 110.22.

thanks

430.1 Scope. This article covers motors, motor branchcircuit
and feeder conductors and their protection, motor
overload protection, motor control circuits, motor controllers,
and motor control centers.

430 only covers motor related circuits and equipment. It even says so right in 430.1.

430.113 only covers motors that have multiple power sources (which is not real common).

This is more of a safety and LOTO issue than it is a NEC issue.

However, NFPA79 is a little more explicit, if you follow those rules.

5.3.5.4 Where circuits are not disconnected by the supply
circuit disconnecting means, all of the following requirements
shall be met:
(1) Permanent warning label(s) shall be placed adjacent to
the supply circuit disconnecting means indicating that it
does not de-energize all exposed live parts when it is in
the open (off) (isolated) position.
(2) A corresponding statement shall be included in the machine
documentation.
(3) Apermanent warning label shall be placed in proximity to
each excepted circuit, or shall be identified by color as
defined in 14.2.4.

 

[petersonra]

BTW - does anyone know where i can buy a premade signe that says something like "Warning - Circuits in yellow wire not disconnected by main disconencting means". One of those cheap stickers would be ideal.