eLCOSH : Electrical Safety: Safety & Health for Electrical Trades (Student Manual)

Electrical Safety: Safety & Health for Electrical Trades (Student Manual)

Share this using: |

Safety Model Stage 3—Controlling Hazards: Safe Work Practices

How Do You Work Safely?

A safe work environment is not enough to control all electrical hazards. You must also work safely. Safe work practices help you control your risk of injury or death from workplace hazards. If you are working on electrical circuits or with electrical tools and equipment, you need to use safe work practices.

Before you begin a task, ask yourself:

What could go wrong?
Do I have the knowledge, tools, and experience to do this work safely?

All workers should be very familiar with the safety procedures for their jobs. You must know how to use specific controls that help keep you safe. You must also use good judgment and common sense.

Control electrical hazards through safe work practices.

Plan your work and plan for safety.
Avoid wet working conditions and other dangers.
Avoid overhead powerlines.
Use proper wiring and connectors.
Use and maintain tools properly.
Wear correct PPE.

Plan your work and plan for safety

Take time to plan your work, by yourself and with others. Safety planning is an important part of any task. It takes effort to recognize, evaluate, and control hazards. If you are thinking about your work tasks or about what others think of you, it is hard to take the time to plan for safety. But, YOU MUST PLAN.

Plan to be safe.

Don't work alone.

A 40-year-old male meter technician had just completed a 7-week basic lineman training course. He worked as a meter technician during normal working hours and as a lineman during unplanned out-ages. One evening, he was called to repair a residential power outage. By the time he arrived at the site of the outage, he had already worked 2 hours of overtime and worked 14 straight hours the day before. At the site, a tree limb had fallen across an overhead powerline. The neutral wire in the line was severed, and the two energized 120-volt wires were disconnected. The worker removed the tree limb and climbed up a power pole to reconnect the three wires. He was wearing insulated gloves, a hard hat, and safety glasses.

He prepared the wires to be connected. While handling the wires, one of the energized wires caught the cuff of his left glove and pulled the cuff down. The conductor contacted the victim’s forearm near the wrist. He was electrocuted and fell backwards. He was wearing a climbing belt, which left him hanging upside down from the pole. Paramedics arrived 5 minutes after the contact. The power company lowered his dead body 30 minutes later.

Several factors may have contributed to this incident. Below are some ways to eliminate these risk factors.

Ask for assistance when you are assigned tasks that cannot be safely completed alone. The task assigned to the victim could not have been done safely by only one person.
Do not work overtime performing hazardous tasks that are not part of your normal assignments.
Employees should only be given tasks that they are qualified to perform. All employees below the journeyman level should be supervised.

Test circuits to make sure they are de-energized.

Planning with others is especially helpful. It allows you to coordinate your work and take advantage of what others know about identifying and controlling hazards. The following is a list of some things to think about as you plan.

Work with a “buddy”—Do not work alone. Both of you should be trained in CPR. Both of you must know what to do in an emergency.

Know how to shut off and de-energize circuits—You must find where circuit breakers, fuses, and switches are located. Then, the circuits that you will be working on (even low-voltage circuits) MUST BE TURNED OFF! Test the circuits before beginning work to make sure they are completely de-energized.

This worker is applying a group lock-out device. The equipment cannot be re-started until all workers remove their locks.

Plan to lock out and tag out circuits and equipment—Make certain all energy sources are locked out and tagged out before performing any work on an electrical circuit or electrical device. Working on energized (“hot”) circuits is one of the most dangerous things any worker could do. If someone turns on a circuit without warning, you can be shocked, burned, or electrocuted. The unexpected starting of electrical equipment can cause severe injury or death.

Before ANY work is done on a circuit, shut off the circuit, lock out and tag out the circuit at the distribution panel, then test the circuit to make sure it is de-energized.

Before ANY equipment inspections or repairs—even on so-called low-voltage circuits—the current must be turned off at the switch box, and the switch must be padlocked in the OFF position. At the same time, the equipment must be securely tagged to warn everyone that work is being performed. Again, test circuits and equipment to ensure they are de-energized.

No two locks should be alike. Each key should fit only one lock, and only one key should be issued to each worker. If more than one worker is working on a circuit or repairing a piece of equipment, each worker should lock out the switch with his or her own lock and never permit anyone else to remove it. At all times, you must be certain that you are not exposing other workers to danger. Workers who perform lock-out/tag-out must be trained and authorized to repair and maintain electrical equipment. A locked-out switch or feeder panel prevents others from turning on a circuit. The tag informs other workers of your action.
Remove jewelry and metal objects—Remove jewelry and other metal objects or apparel from your body before beginning work. These things can cause burns if worn near high currents and can get caught as you work.
Plan to avoid falls—Injuries can result from falling off scaffolding or ladders. Other workers may also be injured from equipment and debris falling from scaffolding and ladders.

A worker was attempting to correct an electrical problem involving two non-operational lamps. He examined the circuit in the area where he thought the problem was located. He had not shut off the power at the circuit breaker panel and did not test the wires to see if they were live. He was electrocuted when he grabbed the two live wires with his left hand. He collapsed to the floor and was found dead.

Employers should not allow work to be done on electrical circuits unless an effective lock-out/tag-out program is in place.
No work should be done on energized electrical circuits. Circuits must be shut off, locked out, and tagged out. Even then, you must test the circuit before beginning work to confirm that it is de-energized (“dead”).

Ladder Safety Fact Sheet

To prevent injury when climbing, follow these procedures:

1. Position the ladder at a safe angle to prevent slipping. The horizontal distance from the base of the ladder to the structure should be one-quarter the length of the ladder. If you don’t have a way
to make this measurement, follow the steps below to determine if the ladder is positioned at a safe angle.

Put your feet at the base of the ladder and extend your arms straight out.
If you can touch the closest part of the ladder without bending your arms, the ladder is probably at the correct angle.
If you have to bend your arms to touch the closest part of the ladder or if you can’t reach the ladder at all, the ladder is not positioned at a safe angle.

2. Make sure the base of the ladder has firm support and the ground or floor is level. Be very careful when placing a ladder on wet, icy, or otherwise slippery surfaces. Special blocking may be needed to prevent slipping in these cases.

3. Follow the manufacturer’s recommendations for proper use.

4. Check the condition of the ladder before using it. Joints must be tight to prevent wobbling or leaning.

5. When using a stepladder, make sure it is level and fully open. Always lock the hinges. Do not stand on or above the top step.

6. When using scaffolding, use a ladder to access the tiers. Never climb the cross braces.

7. Do not use metal ladders. Instead, use ladders made of fiberglass. (Although wooden ladders are permitted, wood can soak up water and become conductive.)

8. Beware of overhead powerlines when you work with ladders and scaffolding.

Learn how to use ladders and scaffolding properly.

A crew of 7 workers was painting a 33-foot sign at a shopping mall. The crew used tubular welded frame scaffolding that was 31 feet tall and made up of several tiers. The sign was partially painted when the crew was instructed to move the scaffolding so that concrete could be poured for an access road. The crew moved the scaffolding 30 feet without disassembling it. An overhead powerline was located about 10 feet away from the scaffolding. After the concrete hardened, the workers lifted the scaffolding to move it back to the sign. The top tier came loose, fell, and contacted the powerline. All seven workers were knocked away from the scaffolding. Two died; five were hospitalized.

You must take certain precautions when working with scaffolding.

Scaffolding should not be moved until all potential safety hazards are identified and controlled. In this case, the scaffolding should have been taken apart before it was moved.
Locking pins must be used to secure tiers to one another.
Always make sure you have enough time to complete your assignment safely. If you are rushed, you may be more likely to take deadly short-cuts (such as failing to dismantle scaffolding before moving it).
Employers must have a written safety program that includes safe work procedures and hazard recognition.

Do not do any tasks that you are not trained to do or that you do not feel comfortable doing!

A company was contracted to install wiring and fixtures in a new office complex. The third floor was being prepared in a hurry for a new tenant, and daily changes to the electrical system blueprints were arriving by fax. The light fixtures in the office were mounted in a metal grid that was fastened to the ceiling and properly grounded.

A 23-year-old male apprentice electrician was working on a light fixture when he contacted an energized conductor. He came down from the fiberglass ladder and collapsed. Apparently, he had contacted the “hot” conductor while also in contact with the metal grid. Current passed through his body and into the ground-ed grid. Current always takes a path to ground. In this case, the worker was part of that path.

He was dead on arrival at a nearby hospital. Later, an investigation showed that the victim had cross-wired the conductors in the fixture by mistake. This incorrect wiring allowed electricity to flow from a live circuit on the completed section of the building to the circuit on which the victim was working.

Below are some safety procedures that should have been followed in this case. Because they were ignored, the job ended in death.

Before work begins, all circuits in the immediate work area must be shut off, locked out, and tagged out—then tested to confirm that they are de-energized.
Wiring done by apprentice electricians should be checked by a journeyman.
A supervisor should always review changes to an original blueprint in order to identify any new hazards that the changes might create.

Avoid wet working conditions and other dangers

Remember that any hazard becomes much more dangerous in damp or wet conditions. To be on the safe side, assume there is dampness in any work location, even if you do not see water. Even sweat can create a damp condition!

Avoid wet conditions! Even avoid damp conditions!

Portable GFCI.

Do not work wet—Do not work on circuits or use electrical equipment in damp or wet areas. If necessary, clear the area of loose material or hanging objects. Cover wet floors with wooden planking that can be kept dry. Wear insulating rubber boots or shoes. Your hands must be dry when plugging and unplugging power cords and extension cords. Do not get cleaning solutions on energized equipment.

Use a GFCI—Always use a GFCI when using portable tools and extension cords.

Avoid overhead powerlines

Be very careful not to contact overhead powerlines or other exposed wires. More than half of all electrocutions are caused by contact with overhead lines. When working in an elevated position near overhead lines, avoid locations where you (and any conductive object you hold) could contact an unguarded or uninsulated line. You should be at least 10 feet away from high-voltage transmission lines.

Vehicle operators should also pay attention to overhead wiring. Dump trucks, front-end loaders, and cranes can lift and make contact with overhead lines. If you contact equipment that is touching live wires, you will be shocked and may be killed. If you are in the vehicle, stay inside. Always be aware of what is going on around you.

A worker from an electrical service company was changing bulbs in pole-mounted light fixtures in a shopping center parking lot. The procedure for installing the bulbs was as follows: The worker would park the truck near the first light pole. The truck was equipped with a roof-mounted ladder. The worker would extend the ladder high enough to change the bulb, then drive to the next pole without lowering the ladder.

After the worker replaced the first bulb, he got back in the truck and drove toward the next light pole. As the truck moved along, a steel cable attached to the top of the ladder contacted an overhead powerline. The worker realized something was wrong, stopped the truck, and stepped onto the pavement while still holding onto the door of the truck. By doing this, he completed the path to ground for the current in the truck. Because the ladder was still in contact with the powerline, the entire truck was now energized. He was engulfed in flames as the truck caught fire. Fire, police, and paramedic units arrived within 5 minutes. Utility workers arrived in
about 10 minutes and de-energized (shut off) the powerline. The victim burned to death at the scene.

Below are some ways to prevent contact with overhead powerlines.

A safe distance must be maintained between ladders (and other equipment) and overhead lines. OSHA requires that a clearance of at least 10 feet be maintained between aerial ladders and overhead powerlines of up to 50,000 volts.
Moving a truck with the ladder extended is a dangerous practice. One way to control this hazard is to install an engine lock that prevents a truck’s engine from starting unless the ladder is fully retracted.
If there are overhead powerlines in the immediate area, lighting systems that can be serviced from ground level are recommended for safety.
If the worker had been trained properly, he may have known to stay inside the truck.
Pre-job safety surveys should always be performed to identify and control hazards. In this case, a survey would have identified the powerlines as a possible hazard, and appropriate hazard control measures (such as lowering the ladder between installations) could have been taken.

Use proper wiring and connectors

Avoid overloads—Do not overload circuits.
Test GFCI’s—Test GFCI’s monthly using the “test” button.
Check switches and insulation—Tools and other equipment must operate properly. Make sure that switches and insulating parts are in good condition.

Never use a three-prong grounding plug with the third prong broken off.
Use three-prong plugs—Never use a three-prong grounding plug with the third prong broken-off. When using tools that require a third-wire ground, use only three-wire extension cords with three-prong grounding plugs and three-hole electrical outlets. Never remove the grounding prong from a plug! You could be shocked or expose someone else to a hazard. If you see a cord without a grounding prong in the plug, remove the cord from service immediately.
Use extension cords properly—If an extension cord must be used, choose one with sufficient ampacity for the tool being used. An undersized cord can overheat and cause a drop in voltage and tool power. Check the tool manufacturer’s recommendations for the required wire gauge and cord length. Make sure the insulation is intact. To reduce the risk of damage to a cord’s insulation, use cords with insulation marked “S” (hard service) rather than cords marked “SJ” (junior hard service). Make sure the grounding prong is intact. In damp locations, make sure wires and connectors are waterproof and approved for such locations. Do not create a tripping hazard.
Check power cords and extensions—Electrical cords should be inspected regularly using the following procedure:
You should also test electrical cords regularly for ground continuity
using a continuity tester as follows:
Do not pull on cords—Always disconnect a cord by the plug.
Use correct connectors—Use electrical plugs and receptacles that are right for your current and voltage needs. Connectors are designed for specific currents and voltages so that only matching plugs and receptacles will fit together. This safeguard prevents a piece of equipment, a cord, and a power source with different voltage and current requirements from being plugged together. Standard configurations for plugs and receptacles have been

Locking-type attachment plug.

established by the National Electric Manufacturers Association (NEMA).
Use locking connectors—Use locking-type attachment plugs, receptacles, and other connectors to prevent them from becoming unplugged.

Use and maintain tools properly

Your tools are at the heart of your craft. Tools help you do your job with a high degree of quality. Tools can do something else, too. They can cause injury or even death! You must use the right tools for the job. Proper maintenance of tools and other equipment is very important. Inadequate maintenance can cause equipment to deterio-rate, creating dangerous conditions. You must take care of your tools so they can help you and not hurt you.

Maintain tools and equipment.

Inspect your equipment before you use it.

This cord has been spliced using a wire nut. Spliced cords are very dangerous!

Inspect tools before using them—Check for cracked casings, dents, missing or broken parts, and contamination (oil, moisture, dirt, corrosion). Damaged tools must be removed from service and properly tagged. These tools should not be used until they are repaired and tested.
Use the right tool correctly—Use tools correctly and for their intended purposes. Follow the safety instructions and operating procedures recommended by the manufacturer. When working on a circuit, use approved tools with insulated handles. However, DO NOT USE THESE TOOLS TO WORK ON ENERGIZED CIRCUITS. ALWAYS SHUT OFF AND DE-ENERGIZE CIRCUITS BEFORE BEGINNING WORK ON THEM.
Protect your tools—Keep tools and cords away from heat, oil, and sharp objects. These hazards can damage insulation. If a tool or cord heats up, stop using it! Report the condition to a supervisor or instructor immediately. If equipment has been repaired, make sure that it has been tested and certified as safe before using it. Never carry a tool by the cord. Disconnect cords by pulling the plug—not the cord!
Use double-insulated tools—Portable electrical tools are classified by the number of insulation barriers between the electricalconductors in the tool and the worker. The NEC permits the use
of portable tools only if they have been approved by Underwriter’s Laboratories (UL Listed). Equipment that has two insulation barriers and no exposed metal parts is called double-insulated.
When used properly, double-insulated tools provide reliable shock protection without the need for a third ground wire. Power tools with metal housings or only one layer of effective
insulation must have a third ground wire and three-prong plug.
Use multiple safe practices—Remember: A circuit may not be wired correctly. Wires may contact other “hot” circuits. Someone else may do something to place you in danger. Take all possible precautions.

An employee was climbing a metal ladder to hand an electric drill to the journeyman installer ona scaffold about 5 feet above him. When the victim reached the third rung of the ladder, he received an electrical shock that killed him. An investigation showed that the grounding prong was missing from the extension cord attached to the drill. Also, the cord’s green grounding wire was, at times, contacting the energized black wire. Because of this contact with the "hot" wire, the entire length of the grounding wire and the drill’s frame became energized. The drill was not double-insulated.

To avoid deadly incidents like this one, take these precautions:

Make certain that approved GFCI’s or equipment grounding systems are used at construction sites.
Use equipment that provides a permanent and continuous path to ground. Any fault current will be safely diverted along this path.
Inspect electrical tools and equipment daily and remove damaged or
defective equipment from use right away.

Use the right tools and equipment.

Do not work on energized circuits.

Don’t work on energized circuits like this one! Always follow correct lock-out/tag-out procedures.

A 22-year-old male carpenter was building the wooden framework of a laundry building. He was using portable power tools. Electricity was supplied to the tools by a temporary service pole 50 feet away. The service pole had not been inspected and was not in compliance. It was also not grounded. The carpenter plugged a “homemade” cord into the service pole and then plugged a UL-approved cord into the homemade cord. His power saw was plugged into the UL-approved cord.

The site was wet. Humidity was high and the carpenter was sweating. Reportedly, he was mildly shocked throughout the morning and replaced the extension cord he was using in an effort to stop the shocks. At one point, as he was climbing down a makeshift ladder constructed from a floor truss, he shifted the power saw from his right hand to his left hand and was shocked. He fell from the ladder into a puddle of water, still hold-ing the saw. The current had caused his hand to contract, and he was “locked” to the saw. A co-worker disconnected the power cord to the saw. CPR was given, but the shock was fatal.

Attention to these general safety principles could have prevented this death.

Any and all electrical equipment involved in a malfunction should be taken out of service immediately. The carpenter should have taken the saw out of service, not just the extension cord. (As it turns out, the saw was the source of the shocks, not the cord.)
Although the homemade extension cord does not seem to have contributed to this incident, it should not have been used.
The floor truss should not have been used as a ladder. For climbing, use only approved ladders or other equipment designed specifically for climbing.
Do not work in wet areas. The water should have been removed from the floor as soon as it was found. Humidity and perspiration can also be hazards. Try to stay as dry as possible, be alert, and take action to protect yourself when needed.
OSHA requires that all receptacles at construction sites that are not part of the permanent wiring have GFCI’s.
Be aware that shocks can cause you to lose your balance and fall, often resulting in more severe injury.

Wear correct PPE

OSHA requires that you be provided with personal protective equipment. This equipment must meet OSHA requirements and be appro-priate for the parts of the body that need protection and the work performed. There are many types of PPE: rubber gloves, insulating shoes and boots, face shields, safety glasses, hard hats, etc. Even if laws did not exist requiring the use of PPE, there would still be every reason to use this equipment. PPE helps keep you safe. It is the last line of defense between you and the hazard.

Wear and maintain PPE.

Wear safety glasses—Wear safety glasses to avoid eye injury.

Wear safety glasses to avoid eye injury.
Wear proper clothing—Wear clothing that is neither floppy nor too tight. Loose clothing will

Don't wear hard hats backwards!

catch on corners and rough sur-faces. Clothing that binds is uncomfortable and distracting.
Contain and secure loose hair—Wear your hair in such a way that it does not interfere with your work or safety.
Wear proper foot protection—Wear shoes or boots that have been approved for electrical work. (Tennis shoes will not protect you from electrical hazards.) If there are non-electrical hazards present (nails on the floor, heavy objects, etc.), use footwear that is approved to protect against these hazards as well.
Wear a hard hat—Wear a hard hat to protect your head from bumps and falling objects. Hard hats must be worn with the bill forward to protect you properly.
Wear hearing protectors—Wear hearing protectors in noisy areas to prevent hearing loss.
Follow directions—Follow the manufacturer’s directions for cleaning and maintaining PPE.
Make an effort—Search out and use any and all equipment that will protect you from shocks and other injuries.

Arcing electrical burns through the victim’s shoe and around the rubber sole.

Think about what you are doing.

PPE is only effective when used correctly.

PPE Fact Sheet—The Right Equipment—Head to Toe

PPE is the last line of defense against workplace hazards. OSHA defines PPE as "equipment for the eyes, face, head, and extremities, protective clothing, respiratory devices, protective shields and barriers." Many OSHA regulations state that PPE must meet criteria set by the American National Standards Institute (ANSI).

Head Protection

Head Protection

OSHA requires that head protection (hard hats) be worn if there is a risk of head injury from electrical burns or falling/flying objects.

Aren’t all hard hats the same?

No. You must wear the right hat for the job. All hard hats approved for electrical work made since 1997 are marked "Class E." Hard hats made before 1997 are marked "Class B." These markings will be on a label inside the helmet or stamped into the helmet
itself. Newer hats may also be marked "Type 1" or "Type 2." Type 1 hard hats protect you from impacts on the top of your head. Type 2 hard hats protect you from impacts on the top and sides of your head.


Class E, Type 1 hard hat.	Class B hard hat.

Don’t wear another hat under your hard hat!

How do I wear and care for my hard hat?

Always wear your hat with the bill forward. (Hats are tested in this position.) If you wear a hat differently, you may not be fully protected. The hat should fit snugly without being too tight. You should clean and inspect your hard hat regularly according to the manufacturer’s
instructions. Check the hat for cracks, dents, frayed straps, and dulling of the finish. These conditions can reduce protection. Use only mild soap and water for cleaning. Heavy-duty cleaners and other chemicals can damage the hat.

Do not "store" anything (gloves, wallet, etc.) in the top of your hard hat while you are wearing it. The space between the inside harness and the top of the hard hat must remain open to protect you. Do not put stickers on your hat (the glue can weaken the helmet) and keep it out of direct sunlight. If you want to express your personality, hard hats come in many colors and can be imprinted with custom designs by the manufacturer. Some hats are available in a cowboy hat design or with sports logos.


Never “store” anything in the top of your hard hat while you are wearing it.	Class B hard hat in a cowboy hat design.

Keep your hard hat out of direct sunlight when you are not wearing it!

Use your head and protect your head!

Foot Protection

Foot Protection

Workers must wear protective footwear when there is a risk of foot injury from sharp items or falling/rolling objects—or when electrical hazards are present. As with hard hats, always follow the manufacturer’s instructions for cleaning and maintenance of footwear. Remember that cuts, holes, worn soles, and other damage can reduce protection.

How do I choose the right footwear?

The footwear must be ANSI approved. ANSI approval codes are usually printed inside the tongue of the boot or shoe. Footwear will be marked "EH" if it is approved for electrical work. (The ANSI approval stamp alone does not necessarily mean the footwear offers protection from electrical hazards.) Note that footwear made of leather must be kept dry to protect you from electrical hazards, even if it is marked "EH."

What about non-electrical hazards?

All ANSI approved footwear has a protective toe and offers impact and compression protection. But the type and amount of protection is not always the same. Different footwear protects you in different ways. Check the product’s labeling or consult the manufacturer to make sure the footwear will protect you from the hazards you face.

Don’t take risks because you are wearing PPE. PPE is the last line of defense against injury!

Summary of Section 8

Control hazards through safe work practices.

Plan your work and plan for safety.
Avoid wet working conditions and other dangers.
Avoid overhead powerlines.
Use proper wiring and connectors.
Use and maintain tools properly.
Wear correct PPE.

Back to Table of Contents

This paper appears in the eLCOSH website with the permission of the author and/or copyright holder and may not be reproduced without their consent. eLCOSH is an information clearinghouse. eLCOSH and its sponsors are not responsible for the accuracy of information provided on this web site, nor for its use or misuse.