Meeting labeling codes
Engineers involved in the specification, design, installation, or relocation of equipment should understand electrical panel labeling requirements needed to meet national codes and OSHA standards for individual state laws. A component that has a listed label, such as Underwriters Laboratories Inc . (UL), has been subjected to test and evaluation, meaning the listed component meets the nationally recognized safety standards. Appropriate labeling, including incoming power, short-circuit current ratings, and required personal protection equipment, provides the information needed to install and maintain equipment in a safe and reliable manner.
Electrical panel identification with manufacturing labeling is a necessity when dealing with a company's purchasing, inventory, quality assurance, and asset tracking requirements. In addition to the business operational side of equipment panel labeling, there are the legal requirements for electrical products to be listed and labeled. For instance, Minnesota Rule 3800.3620 (Renumbered 3801.3619) states, "All electrical equipment, including material, fittings, devices, apparatus, fixtures, appliances, and utilization equipment, used as part of, or in connection with, an electrical installation shall be listed and labeled by a testing laboratory."
There are alternatives to having equipment listed and labeled. For industrial equipment to be "safe" it must be in compliance with the Code of Federal Regulations, Title 29, Section 1910.399 (1991), which states:
D. Custom-made electrical equipment or related installations that are designed and manufactured to a purchaser's specifications and are not marketed to the general public are exempt from listing and labeling requirements. Equipment or installations exempt under this item are subject to the following:
they must be determined to be safe for their intended use by the manufacturer on the basis of test data which the purchaser keeps and makes available to the electrical inspection authority having jurisdiction, as required by Code of Federal Regulations, title 29, part 1910.399 (1991), for equipment or installations subject to national occupational safety and health laws; or
they must be inspected by the electrical inspection authority having jurisdiction for compliance with the construction requirements of the applicable electrical standards used by electrical testing laboratories to evaluate the equipment, or the National Electrical Code. Schematic wiring diagrams, component layout diagrams, and component electrical rating information shall be provided to enable evaluation under this sub item.
Pieces of electrical equipment often require examination, adjustment, servicing, or maintenance while energized. The labeling on these pieces of equipment should be field marked to warn workers of potential electric arc flash hazards. For example, the National Electric Code (NFPA 70), Article 110.16 requires labeling for arc flash and shock hazard protection. Arc flash is the energy released from short circuit current condition between conductors at different potentials. In situations of high potential, the resulting energy release can cause radiant energy and high-temperature shock injury waves, resulting in injury or even death of unprotected individuals.
NEC Article 110.16 lists NFPA 70E-2004, "Standard for Electrical Safety in the Workplace." This standard provides assistance in determining the severity of potential exposure, planning safe work practices, and selecting personal protective equipment.
The NEC has labeling requirements for specific equipment such as air conditioning, control panels, and machine data, such as:
Article 440.5 Air Conditioning and Refrigeration Equipment: lists the requirements of manufacturer's name, trademark, voltage, phase, full-load, and locked-rotor current ratings.
Article 670.3 Machine Nameplate Data: lists information required for nameplates on control equipment, including such information as supply voltage, phase, frequency, full load current, and short-circuit current rating of the control panel.
Article 409.110 Industrial Control Panels: requires all industrial control panels to be marked with a short circuit current rating (SCCR). The fine print lists UL 508A-2001, Supplement SB, as an example of an approved method.
In addition to the National Electric Code, another standard used to regulate labeling of electrical panels within facilities is the Electrical Standard for Industrial Machinery (NFPA 79).
NFPA 79, Section 16.2.7 states, "A safety sign shall be provided adjacent to the main supply circuit disconnect operating handle 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," and Section 67.1.2 declares, "When provided with main overcurrent protection, the nameplate shall include 'Short circuit rating of the protective device' in amperes and 'overcurrent projection provided at main supply terminals.'"
Technically, equipment installed before 2002 needs to be labeled if the equipment has been modified or upgraded. A NEC survey indicated that only 14% of equipment installed prior to 2002 was labeled. If the equipment is moved, the arc flash and SCCR rating must be evaluated and the appropriate labeling provided.
<table ID = 'id4369812-0-table' CELLSPACING = '0' CELLPADDING = '2' WIDTH = '100%' BORDER = '0'><tbody ID = 'id4370088-0-tbody'><tr ID = 'id4369977-0-tr'><td ID = 'id4369979-0-td' CLASS = 'table' STYLE = 'background-color: #EEEEEE'> Author Information </td></tr><tr ID = 'id4369988-3-tr'><td ID = 'id4369990-3-td' CLASS = 'table'>Hochrein is a licensed electrical engineer in Wisconsin and Minnesota and holds a Minnesota Master Electrician license. He has provided design and consulting services for facility power, fire alarm, egress and general lighting applications.</td></tr></tbody></table>
Not labeling can be costly
In 2008, OSHA fines related to improper labeling were number 3 on the administration's top 10 list of violations according to fine dollar amount. Number 4 was related to operating equipment in a safe manner.
OSHA violations with the highest total fines in 2008
Fall protection, construction
Scaffolding, general requirements
Electrical hazard communication standard, general industry
Control of hazardous energy (lockout/tagout), general industry
Excavations, requirements for protective systems, construction