Guide to Electrical Safety
Electrical hazards are the cause of many preventable accidents each year. It is important for all employees to be familiar with electrical safety procedures in order to avoid these misfortunes. Check out PE Facts to learn more about electrical safety and how to minimize electrical hazards in your work environment!
HazCom, Lockout/Tagout and Confined Spaces are usually thought of immediately when addressing occupational health and safety issues while electrical safety typically gets overlooked. OSHA however, has designated a large section of the Code of Federal Regulations (29 CFR 1910 Subpart S) for electrical safety. If you have a Lockout/Tagout program, electrical safety is an important part of that program.
There are certain occupations that are at a higher risk, such as electricians, supervisors, machine operators, painters and welders. But no matter what your job, there are electrical hazards that should be evaluated in any facility. By creating and implementing a strong, well-defined electrical program, you can lessen the risks of electrical hazards.
Qualified Personnel vs. Unqualified Personnel
Two terms that are frequently used in electrical safety are Qualified Person and Unqualified Person. A Qualified Person is someone who has been properly trained to avoid electrical hazards when working closely with exposed energized parts. A Qualified Person must be:
- Familiar with the safety related work practices required in 29 CFR 1910.331-1910.335;
- Able to identify exposed live parts of electrical equipment
- Knowledgeable of the skills and techniques used to determine the nominal voltages of exposed parts; and
- Trained to approach distances to which a Qualified Person will be exposed. (See Table 1)
An Unqualified Person is a person who has had little or no training concerning electrical hazards. Even though Unqualified Persons may not be exposed to energized parts, they should still be trained for such situations. At the very least, the Unqualified Person must be taught electrical-related safety practices. This could be considered something as simple as telling an Unqualified Person that if there is a problem, to shut off the machine and call a supervisor for assistance.
Work Practices
Safety-related work practices are utilized to avoid electrical shock or injury. Live parts must be de-energized before an Unqualified Person should be working anywhere near them. (Exception: live parts that operate at less than 50V to ground do not need to be de-energized as long as there is no chance for increased exposure to electrical burns or explosions due to arcing.)
The electrical energy source(s) must be disconnected from the equipment in order to be de-energized. Just using the designated controls to shut the equipment off (i.e. switches, push buttons or interlocks) does not count as de-energizing; the entire unit must also be properly disconnected.
After the electrical power has been disconnected from the equipment, a Qualified Person must then confirm that the equipment is de-energized. They must do this by operating the controls to first confirm that the equipment will not restart unexpectedly. Second, they must use the test equipment to monitor the electrical parts to which employees will be exposed to confirm that they are also de-energized.
As the standard states, the test equipment must be checked to see if it is functioning properly before and immediately after the verification test if the circuit is over 600V (To ensure readings are accurate, test equipment should always be checked before and after no matter what the voltage is.). If this process does not take place, the equipment is still considered “energized.” After de-energization is complete, follow the remaining procedures as stated in your facility’s lockout/tagout program.
If there are open live parts that are not de-energized (due to an increased risk or infeasibility), other safety-related work practices must be used. Any electrical equipment that has not been de-energized can only be worked on by a Qualified Person. In addition, Qualified Personnel must be familiar with special precautionary techniques, personal protective equipment, insulating materials and insulated tools.
Insulated Tools
The use of Insulated tools is required for any Qualified Person who is working on or near exposed energized live conductors. Only insulated tools that meet the International Electrotechnical Commission standard 900 (IEC 900), and are marked with the international 1000V rating symbol should be used. Just because a tool has a plastic coating or a plastic handle, it doesn’t mean that it will provide protection from electrical shock. This is why it is a good idea to always inspect your tools before performing electrical work. Also, if the insulation becomes damaged or worn, the tool must be removed from service and destroyed.
Electrical Protective Equipment
Electrical Protective Equipment—also known as Insulating Equipment—refers to items such as matting, gloves, sleeves, insulated blankets, and line hose. Blankets, gloves and sleeves are all distinctly marked with their Class and Type. The Class refers to the maximum use voltage. Insulating equipment must not exceed maximum use voltages (See Table 2). The Type marking refers to its ozone resistance. Type I is not ozone resistant; Type II is ozone resistant.
Insulated equipment must be inspected before each days work, as well as directly after any incident that may have caused it damage. Insulated equipment should not be used if it is found to have any of the following defects:
- Holes, tears, punctures, cuts;
- Ozone cutting or checking;
- Embedded foreign object(s);
- Swelling, softening, hardening, loses elasticity or becomes sticky; or
- Any other defect.
If insulated equipment is removed from service, it is loses its certification and may not be used again until it is retested. All electrically-insulated equipment must occasionally be retested and certified; the retesting period changes depending on the type of equipment. (See Table 3).
When wearing insulated rubber gloves, protector gloves—usually made of leather—should be worn over them. The two instances in which protector gloves are not required are:
- Class 0 gloves where high finger dexterity is necessary; or
- When a person uses a glove that is one class higher than is required, in a situation where there’s a small chance of damage. (The problem with doing this is that the insulated glove may not be used again at that higher voltage rate until it has been retested and certified.)
Commonly Asked Questions
| Q. | Is it necessary for insulated equipment to be approved or certified? |
| A. | Insulated equipment must be certified by the manufacturer to be acceptable for—given the proper usage—the specified conditions to which they are exposed. The certificate identifies the equipment and the date it was tested. |
| Q. | Does insulated equipment have an expiration date after which it must be destroyed? |
| A. | No. As long as the insulated equipment is in a safe, dependable condition and retested periodically as required by 29 CFR 1910.137, you may continue to use it. (See Table 3.) |
| Q. | Is there a difference between an Authorized Employee (Lockout/Tagout) and a Qualified Person (Electrical Safety)? |
| A. | Yes. An Authorized Employee is someone who may only lock out machines or equipment in order to perform servicing or maintenance. An Authorized Employee can then either be considered Qualified or Unqualified to de-energize electrical equipment as defined by the electrical standards. |
| Q. | What approach distances should Unqualified Persons use? |
| A. | For voltages of 50kV or less, 10 feet. For voltages greater than 50kV, 10 feet plus an additional 4 inches for every 10kV above 50kV. |
References
Table 1: Approach Distances for Qualified Personnel
| Voltage Range | Minimum Approach Distance |
| 300V or less | Avoid Contact |
| Over 300V, but not more than 750V | 12" |
| Over 750V, but not more than 2kV | 1' 6" |
| Over 2kV, but not more than 15kV | 2' |
| Over 15kV, but not more than 37kV | 3' |
| Over 37kV, but not more than 87.5kV | 3' 6" |
| Over 87.5kV, but not more than 121kV | 4' 6" |
| Over 121kV, but not more than over 140kV | 4' 6" |
Table 2: Class and Use Voltages
| Class | Maximum Use Voltage | Proof Test (AC) | Retest Voltage (AC) | Proof Test (DC) | Retest Voltage (DC) |
| 0 | 1,000 | 5,000 | 5,000 | 20,000 | 20,000 |
| 1 | 7,500 | 10,000 | 10,000 | 40,000 | 40,000 |
| 2 | 17,000 | 20,000 | 20,000 | 50,000 | 50,000 |
| 3 | 26,500 | 30,000 | 30,000 | 60,000 | 60,000 |
| 4 | 36,000 | 40,000 | 40,000 | 70,000 | 70,000 |
Table 3: Protective Equipment Test Schedules
| Type of Equipment | When to Test |
| Line Hose | Upon indication that insulating value is suspect |
| Covers | Upon indication that insulating value is suspect |
| Blankets | Before first issue and every twelve months thereafter* |
| Gloves | Before first issue and every six months thereafter* |
| Sleeves | Before first issue and every twelve months thereafter* |
*If insulating equipment has been tested but not issued for service, it may not be placed into service unless it has been tested within the previous 12 months.
Please Note: The information contained in this publication is intended for general information purposes only. This publication is not a substitute for review of the applicable government regulations and standards, and should not be construed as legal advice or opinion. Readers with specific questions should refer to the cited regulation or consult with an attorney.
