Question 2: If 29 CFR 1910.303(g)(2)(i) applies to live parts operating at 50 volts or more AC or DC, will OSHA treat a failure to guard live parts operating below 60 volts DC as … OSHA pointed out that serious injuries occurred in situations where the worker was exposed to only 12 volt- or 24-volt DC vehicle batteries. Some one was asking me how did they come up with the 50 volt threshold, and could I find any documentation on it. Originally adopted in 1971, OSHA’s first construction scaffolding requirements remained relatively unchanged until 1996.
Energized Electrical Work . 1.0 Purpose . Good question. The U.S. Office of Compliance adds that any live parts of equipment operating with at least 50 volts must be protected by NFPA-approved enclosures. The safest way to conduct electrical work is to shut off electric power and work on de-energized equipment.
OSHA 1926 Construction Subpart A General Subpart B General Interpretations ... live parts of electric equipment operating at 50 volts or more shall be guarded against accidental contact by cabinets or other forms of enclosures, or by any of the following means: 1926.403(i)(2)(i)(A) By location in a room, vault, or similar enclosure that is accessible only to qualified persons. To ensure that an electrical panel can be accessed at all times – during inspection, maintenance or emergency – OSHA has determined that the working space in front of the equipment must be at least 30-inches wide (or the width of the equipment). Remember, the 50 Volt limitation is based on contact electrocutions (fatalities by definition) of "qualified" workers, not battery short-circuit explosions or burns. At CSUCI our intent and standard practice will be to avoid energized electrical work. While their 1910 standard states guarding is necessary for electrical equipment for 50V and above, the letter states that equipment under 50 volts is not always completely safe, either. Requirements for working without electrical protective equipment. A clearance of at least 3 feet is required for equipment using 120 to 250 volts. OSHA has no documented cases of electrocutions or serious shock injuries below 60V. Electrical Safety -- Don't Be Shocked!
OSHA 1920.269 (1) (2) (I) states that employees must avoid contact above 50 volts AC unless they are insulated with rubber gloves meeting the ASTM D120 standard (per OSHA 1910.137 (a)). The minimum safe working distances are covered by OSHA (1926.950), but they are all approximately double the "inch per 10,000 volt" rule of … Generally ANY power source will be able to produce substantial current to kill you but most do not supply enough voltage. There are many major changes in the 2002 National Electrical Code (NEC), but none will affect more installations than the change involving motor disconnect locations.
When it is necessary to perform work on energized equipment, OSHA 1910.333(a)(2) requires safety-related work practices to be used and NFPA 70E Article 110.8(B)(1) requires an Electrical Hazard Analysis before work is performed on live equipment operating at 50 volts and higher. The rule of thumb, functionally, is that each 10,000 volts can jump an inch of air.
Safety Procedures . One challenge that's got many electricians, safety trainers, and frontline workers confused is the definition of low voltage. The letter’s two questions. The 1996 revisions are performance-based, which means the standards do not tell users specifically what to do. This depends on a lot of other environmental factors, however. Does the electrical guarding requirement at 29 CFR 1910.303(g)(21)(i) apply to voltages below 60 volts DC? OSHA’s confined space rule for general industry 29 CFR 1910.146 and construction 1926.1203 do not prescribe the level of detail for lighting requirements described in your policy, because it is up to the employer to evaluate the space to determine the specific hazards and establish the specific controls to protect workers and rescue personnel from those hazards.