Conformity Magazine- May 2008 - (Page 28) proper record keeping and that documented procedures are being followed. Any panels currently in construction at the time of the inspection may also be spot-checked by the NRTL inspector. The panel shop affixes a panel shop approval mark, which differs from NRTL to NRTL, inside the panel. This mark designates that the panel has been constructed to comply with the requirements of UL 508A, Industrial Control Panels, under a supervised panel shop program. Panel Shop Approval and Machine Tools Panel shop approvals for a panel apply only to the industrial control panel, not the entire machine for which the control panel is used. The technical standard, in the scope of the standard, states: “These requirements cover industrial control panels intended for general industrial use, operating from a voltage of 600 volts or less. This equipment is intended for installation in ordinary locations, in accordance with the National Electrical Code, ANSI/NFPA 70, where the ambient temperature does not exceed 40°C (104°F) maximum.3” In particular, the standard specifically states: “An industrial control panel does not include an evaluation of the controlled equipment such as motors, heaters, lighting, and other loads connected to power circuits. Unless specifically noted on the wiring diagram of the industrial control panel, an industrial control panel does not include equipment mounted remotely from the panel and connected via a wiring systems or equipment field installed on or within the industrial control panel.4” In addition, the standard states: “An evaluation of the adequacy of the controls and protective devices contained in an industrial control panel for supervision and proper functioning of the controlled loads or equipment is not covered by the requirements in this standard. Such evaluations are Figure 1: An NRTL panel shop approval from Underwriters Laboratories (UL, Underwriters Laboratories, and the depicted approval marks are trademarks of Underwriters Laboratories). 28 Conformity mAy 2008
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