Module 5: Lesson 2 Electrical Hazards- Other Preventive measures
Type of PPE for Arc Flash Protection
Flame-resistant (FR) clothing and PPE must be used by anyone crossing any part of her or his body into the Flash Protection Boundary as based on the incident energy calculation.
Tool Safety Tips:
- Use gloves and appropriate footwear when using tools. •Store tools in a dry place when not in use. •Don't use tools in wet/damp conditions. •Keep working areas well lit. •Ensure that tools are not a tripping hazard. •Don't carry a tool by the cord. •Don't yank the cord to disconnect the tool from the electrical source. •Keep cords away from heat, oil and sharp edges. •Disconnect tools when not in use and when changing accessories such as, blades and bits. •Remove damage tools from use
Step when Locking out and tagging out of Circuits:
-Apply locks to the power source after de-energizing. •Verify circuit is de-energized by testing with known functioning meters. •Tag deactivated controls and power sources. •Tag de-energized equipment and circuits at all points where they can be energized. •Tags must identify equipment or circuits being worked on.
Control-Assured Equipment Grounding Conductor Program (AEGCP
An employer must use either ground fault circuit interrupters or an assured equipment grounding conductor to protect employees on construction sites. The AEGCP on construction sites must cover: •All cord sets. •Receptacles not part of a building or structure. •Equipment connected by plug and cord available for use by the employer.
Employer safety
As appropriate, the employer shall ensure that all wiring components and utilization equipment in hazardous locations are maintained in a dust-tight, dust-ignition-proof, or explosion-proof condition. There shall be no loose or missing screws, gaskets, threaded connections, seals, or other impairments to a tight condition.
Electrical Protective Devices:
Electrical protective devices automatically open a circuit if excess current from overload or ground-fault is detected, resulting in the shutting off of electricity. Electrical protective devices include GFCIs, fuses, and circuit breakers. Please click each term for more information: •Ground-Fault Circuit Interrupter (GFCI) •Fuses •Circuit Breakers
Energized work:
Energized work must be put into an electrically safe work condition or it must be justified. To justifty energized work, an employer must demonstrate that de-energizing introduces additional or increased hazards, or is infeasible due to equipment design or operational limitations.
Grounding
Grounding creates a low-resistance path from a tool to the earth to disperse unwanted current. When a short or lightning occurs, energy flows to the ground, protecting you from electrical shock, injury, and death.
Energized Electrical Work Permit
If justification for energized work is demonstrated, then the work can be performed only by written permit.
Avoiding Wet Conditions:
If you touch a live wire or other electrical component while standing in even a small puddle of water you'll get a shock. •Damaged insulation, equipment, or tools can expose you to live electrical parts. •Improperly grounded metal switch plates and ceiling lights are especially hazardous in wet conditions. •Wet clothing, high humidity, and perspiration increase your chances of being electrocuted
Power Tool Requirement's:
Power tools must: •Be grounded through a 3-wire cord with one wire going to ground OR be double insulated. •Be double-insulated or be powered by a low-voltage isolation transformer.
GFCI functions:
Protects you from shock. •Detects differences in current as small as 5 mA between the black and white wires. •Shuts off electricity in 1/40th of a second if a ground fault is detected.
Safety Shoes
Safety shoes should be nonconductive and should protect your feet from completing an electrical circuit to ground. Safety shoes can protect against open circuits of up to 600 volts in dry conditions. These shoes should be used with other insulating equipment and in connection with active precautions to reduce or eliminate the potential for providing a path for hazardous electrical energy.
Hard Hats:
Specific types of hard hats are needed when performing electrical work. A "Class E" electrical/utility type hard hat protects against falling objects and high-voltage shock and burns.
Temporary lights
Temporary lights should be protected from contact and damage, and they should not be suspended by cords unless designed to do so.
Conrol- Ground Tools and Equipment:
The following should be taken into consideration when working with tools and equipment: Properly ground power supply systems, electrical circuits, and electrical equipment. •Frequently inspect electrical systems to ensure that the path to ground is continuous. •Inspect electrical equipment before use. •Don't remove ground prongs from tools or extension cords. •Ground exposed metal parts of equipment.
Approach Boundaries to Energized Parts
There are two types of personnel approach boundaries to consider when working on or near energized parts: 1. Shock Protection Boundaries •Limited •Restricted •Prohibited 2. Flash Protection Boundary
Safety- Related work practices:
To protect workers from electrical shock: •Use barriers and guards to prevent passage through areas of exposed energized equipment. •Pre-plan work, post hazard warnings, and use protective measures. •Keep working spaces and walkways clear of cords. •Use special insulated tools when working on fuses with energized terminals. •Don't use worn or frayed cords and cables. •Don't fasten extension cords with staples, hang the cords from nails, or suspend the cords using wire.
Basis for Determining Personal Protective Equipment for Work within a Flash Protection Boundary
When it is determined that work must be performed within a Flash Protection Boundary, the flash hazard analysis must determine, and the employer must document, the incident energy exposure of the worker in cal/cm2.
Preventing Electrical Hazards—Personal Protective Equipment (PPE)
When it is necessary to handle or come close to wires with a potential live electrical charge, it is essential to use proper insulating personal protective equipment (PPE) to protect employees from contact with the hazardous electrical energy. Use the following measures for preventing electrical hazards: •Proper foot protection (not tennis shoes) •Rubber insulating gloves, hoods, sleeves, matting, and blankets •Hard hat (insulated - nonconductive)
Work on circuits:
Work on circuits with voltages less than 50 volts may be performed in an energized state if there is no exposure to electrical burns or explosion risks due to arcs.
Exemptions to Work Permit:
Work that is performed on or near live parts by qualified persons and related to tasks such as testing, troubleshooting, and voltage measuring does not require an energized electrical work permit as long as the appropriate safe work practices and required PPE are used.
Elements of an Energized Electrical Work Permit
•Description and location of the circuit and the equipment involved •Justification for energized work •List of the safe work practices to be applied •Results of a shock hazard analysis •Determination of the shock protection boundaries as noted in NFPA 70E Table 130.2 (C) •Results of an arc flash analysis •The flash protection boundary •Required PPE •Means used to restrict entry of qualified personnel into the work area •Completion of a job briefing, including a discussion of job specific hazards •Authorized and signed energized work approval
(AEGCP) Program Requirement's:
•Specific procedures adopted by the employer (in writing and available for inspection). •A competent person designated by the employer to implement the program. •Daily visual inspection for damage of equipment connected by cords and plugs before use.
Clues that Electrical hazards exist:
•When there are tripped circuit breakers or blown fuses. •When tools, wires, cords, connections, or junction boxes are warmed. •When a GFCI shuts off a circuit. •When there is a worn or frayed insulation around a wire or a connection.