The OSHA Electrical Standard 1910.303(b) requires you to keep electrical equipment “free from recognized hazards likely to cause death or serious physical harm” to workers. There are 2 sets of measures you must take to ensure compliance with electrical equipment requirements: 1. Evaluate the equipment; and 2. Ensure its proper installation and use. Here’s what you need to do for each stage.
Stage 1: Evaluation of Electrical Equipment—8 Factors
You must evaluate the safety of electrical equipment. There are 8 factors to address in your evaluation:
1. The equipment’s suitability for installation and use for its identified purpose. Note:
Listing or labeling of the identified purpose is evidence of suitability, according to OSHA:
2. The mechanical strength and durability of the equipment, including parts designed to enclose and protect other equipment.
3. Wire-bending and connection space.
4. Electrical insulation.
5. Heating effects under all conditions of use.
6. Arcing effects.
7. Classification by type, size, voltage, current capacity and specific use; and
8. Other factors that contribute to the practical safeguarding of persons using or likely to come in contact with the equipment
Stage 2: Electrical Equipment’s Installation and Use—15 Factors
To ensure compliance with installation and use requirements, you need to be able to verify the following 15 things:
1. You install and use listed or labeled equipment in accordance with the instructions in the listing or labeling.
2. Completed wiring installations is free from short circuits and from grounds (other than those required or permitted by Subpart S of the OSHA standard, i.e., the OSHA Electrical Standard).
3. Equipment intended to interrupt current at fault levels has an interrupting rating sufficient for the nominal circuit voltage and the current available at the line terminals of the equipment.
4. Equipment intended to interrupt current at other than fault levels has an interrupting rating at nominal circuit voltage sufficient for the current that must be interrupted.
5. You select and coordinate the over-current, i.e., current exceeding the rated current of equipment or ampacity of a conductor, protective devices, total impedance, component short-circuit current ratings and other characteristics of the circuit to be protected to permit the circuit protective devices used to clear a fault without extensive damage to the electrical components of the circuit. (Note: Assume the fault to be either between 2 or more of the circuit conductors, or between any circuit conductor and the grounding conductor or enclosing metal raceway.)
6. No conductors or equipment is located in (unless it’s specifically identified as being safe for use in that operating environment):
7. Electric equipment is installed in a neat and workmanlike manner.
8. Unused openings in boxes, raceways, auxiliary gutters, cabinets, equipment cases or housings are effectively closed to afford protection substantially equivalent to the wall of the equipment.
9. Conductors are racked to provide ready and safe access in underground and subsurface enclosures that persons enter for installation and maintenance.
10. Internal parts of electrical equipment, including busbars, wiring terminals, insulators and other surfaces, haven’t been damaged or contaminated by foreign materials such as paint, plaster, cleaners, abrasives or corrosive residues.
11. There are no damaged parts that may impair safe operation or mechanical strength of the equipment, e.g., parts that are broken, bent, cut or deteriorated by corrosion, chemical action or overheating.
12. Electric equipment is firmly secured to the surface on which it’s mounted. Note: Wooden plugs driven into holes in masonry, concrete, plaster, or similar materials are not considered secure means of fastening electric equipment.
13. Electric equipment that depends on natural circulation of air and convection principles for cooling of exposed surfaces is installed so that room airflow over such surfaces isn’t prevented by walls or adjacent installed equipment.
14. Equipment designed for floor mounting, clearance between top surfaces and adjacent surfaces is provided to dissipate rising warm air.
15. Electric equipment provided with ventilating openings is installed so that walls or other obstructions don’t prevent the free circulation of air through the equipment.
Go to the SafetySmart Compliance Electricity Compliance Center to get more help complying with OSHA electrical safety requirements: