Design and Installation Requirements

Free from Recognized Hazards

Electrical equipment, including electrical apparatus for research and development, must be free from recognized hazards that are likely to cause death or serious physical harm.  Equipment must be suitable for the installation and use, and must be installed and maintained in accordance with the manufacturer’s instructions. Overloaded circuits, damaged wiring, and defective switches/outlets pose a potential fire hazard. Report any damage or defects to Facilities for repair or replacement.

The National Electric Code (NEC) is an installation code that provides adequate protection for people who use equipment or facilities.  Any installed electrical service or equipment that meets the requirements identified in the NEC will be safe while the equipment is operating normally, provided that it is adequately maintained.  Electrical installations must be in accordance with Virginia Tech's Office of the University Building Official.

If the equipment is not listed or labeled by a Nationally Recognized Testing Laboratory (NRTL), such as custom-built research apparatus or equipment purchased from other countries, review and approval must be completed. Click here for more information.

General Wiring Design and Protection

Work performed on premise wiring or wiring for connection to supply must meet current National Electric Code requirements regardless of who performs the work.  Implementation, including interpretation, inspection, and enforcement of these code requirements is coordinated through the Office of the University Building Official.   Responsibility and costs associated with remediation may fall to the department creating the non-compliant condition. 

Working Space About Electric Equipment

Sufficient access and working space must be provided and maintained around all electric equipment to permit ready and safe operation and maintenance of the equipment.  Working clearances may not be less than 30 inches in front of electric equipment.  Except as permitted by OSHA or the NEC, the working space in front of live parts operating at 600 volts or less that require servicing, inspection or maintenance while energized may not be less than indicated in Table 3.  This working space may not be used for storage.

Labeling

Each disconnecting means (the switch or device used to disconnect the circuit from the power source) must be clearly labeling to indicate the circuit's function unless it is located and arranged so that the purpose is evident. Identification must be specific. All labels and markings must be durable enough to withstand the environment to which they may be exposed. Tape or labels directly attached to breaker switches are not permitted.

Field Marking

OSHA requires that electrical equipment be marked with descriptive markings, including the equipment's voltage, current, wattage, or other ratings as necessary.

NFPA 70E promotes hazard recognition and appropriate personal protective equipment labeling in addition to minimum OSHA labeling. Switchboards, panelboards, industrial control panels, meter sociket enclosures, motor control centers (installed after 2002) that are in other than dwelling occupancies, and any equipment likely to require examination, adjustment, servicing, or maintenance while energized.  This marking is intended to warn qualified persons of potential electric arc flashes before examination, adjustment, servicing, or maintenance of the equipment.  The labels should be located so as to be clearly visible prior to such work.  For equipment installed before 2002, labeling must be applied if any modifications or upgrades take place. Such labeling is the result of a formal arc flash risk analysis, and should be reviewed and updated at least every 5 years.

Guarding of Live Parts

Live parts of electrical equipment operating at 50 volts alternating current (or 100 volts direct current) or more must be guarded against accidental contact by:

• Use of an approved cabinet or other approved enclosure (ex. cover plates, circuit breaker blanks),
• Location in a room or vault that is accessible to qualified persons only, or
• Elevating the equipment, or
• Controlling the arrangement of the space to prevent contact by unqualified persons.

If electrical equipment is located in an area where it is potentially exposed to physical damage, or may fail as in the case of electrical research and developement, the enclosure, location, or barrier must be sufficient enough to prevent such damage beyond the barrier.

Job-Made Cords

Whenever possible, cord sets should be manufactured and listed by a nationally recognized testing laboratory. If job-made cord sets will be assembled by employees, the following requirements must be met.