Playing it safe17 February 2009
Dennis K. Neitzel gives an insight into training requirements to ensure electrical safety
Electrical power systems today are often very complex. Protective devices, controls, instrumentation and interlock systems demand that technicians be trained and qualified at a highly technical skills level. Safety and operating procedures utilised in working on these systems are equally as complex, requiring technicians to be expertly trained in all safety practices and procedures. The goal of any training programme is to develop and maintain an effective and safe work force.
In the US, one objective of the Occupational Safety and Health Administration (OSHA) and the National Fire Protection Association (NFPA) is to protect employees from electrical hazards in the workplace. There must be a strong emphasis on qualified persons only performing work on or near exposed energised and de-energised electrical systems and equipment in all industry sectors. An understanding of the potential hazards of electricity, which include electrical shock, arc-flash and arc-blast, must be addressed as a major part of training and qualifying employees.
One of the most important aspects of electrical safety is to ensure that all employees who are or may be exposed to energised electrical conductors or circuit parts are properly trained and qualified. The first thing that must be discussed is to identify who a qualified person is. This has always been a point of debate throughout industry, but is clearly defined by the National Electrical Code (NEC), NFPA 70E, and OSHA. The NEC defines a qualified person having the ‘skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training on the hazards involved’.
In addition, NFPA states that employees are required to be trained to understand the specific hazards associated with electrical energy, the safety-related work practices and procedural requirements. These training requirements are necessary to help protect employees from the electrical hazards associated with their respective job or task assignments as well as to identify and understand the relationship between electrical hazards and possible injury. Training in emergency procedures is also required when employees are working on or near exposed energised electrical conductors or circuit parts.
OSHA regulations require employers to document that employees have demonstrated proficiency in electrical tasks. A needs assessment is required before any significant training can be developed and implemented for a qualified person. This assessment involves relevant company personnel who are aware of the job requirements and all applicable codes, standards and regulations. Information that is collected will provide insights into any past or present performance problems that must be addressed in the training programme.
Electrical hazards analysis
The results of an electrical hazards analysis constitutes one of the most important factors in the selection of personal protective equipment, developing a training programme for qualified persons, and developing an effective electrical safety programme.
OSHA requires the employer to perform a hazard assessment of the workplace to determine if personal protective equipment (PPE) is necessary. NFPA further defines what is required in the hazard assessment by requiring a shock hazard analysis and a flash hazard analysis for equipment operating at 50V or more. The shock hazard analysis is used to determine the voltage exposure, shock protection boundaries, and the required PPE necessary to protect employees and minimise the possibility of electrical shock.
As a result of the hazard assessment OSHA also requires training. Each employee shall be trained to know at least the following: when PPE is necessary; what PPE is necessary; how to properly don, doff, adjust, and wear PPE; the limitations of the PPE; and the proper care, maintenance, useful life and disposal of the PPE.
NFPA addresses the requirements for arc-rated, flame-resistant (FR) protective clothing and personal protective equipment for application with a flash hazard analysis. When work is to be performed within the flash protection boundary, the flash hazard analysis must be used to determine the incident energy levels that the employee will be exposed to. The incident energy value is then used to select the proper arc-rated, flame-resistant (FR) personal protective clothing and equipment to be used by the employee for the specific task to be performed.
Other PPE that is often overlooked is the requirement to use insulated hand tools. OSHA requires that when working near exposed energised conductors or circuit parts, each employee shall use insulated tools or handling equipment if they might make contact with such conductors or parts.
A common misconception is that when using insulated tools, rubber-insulating gloves are not needed. The primary purpose of rubber gloves is shock protection and the primary purpose of insulated tools is to prevent an electrical arc-flash. They must be used together in order to help avoid electrical hazards.
Electrical safety programme
OSHA states that safety related work practices must be employed to prevent electric shock or other injuries resulting from either direct or indirect electrical contact, when work is performed near or on equipment or circuits which are or may be energised. Energised work applies to work performed on exposed live parts (involving either direct contact or by means of tools or materials) or near enough to them for employees to be exposed to any hazard they present. Conductors and parts of electric equipment that have been de-energised, but have not been locked out or tagged, shall also be treated as energised parts, and this applies to work on or near them.
If the exposed live parts are not de-energised, other safety related work practices must be used to protect employees who may be exposed to the electrical hazards involved. Such work practices will protect employees against contact with energised circuit parts directly with any part of their body or indirectly through some other conductive object.
Only qualified persons should work on electric circuit parts or equipment that have not been de-energised. Such persons should be capable of working safely on energised circuits and must be familiar with the proper use of special precautionary techniques, personal protective equipment, insulating and shielding materials, and insulated tools. If work is to be performed near overhead lines, the lines shall be de-energised and grounded, or other protective measures shall be provided before work is started.
Dennis K. Neitzel currently serves as the Director of AVO Training Institute in Dallas, Texas, US. [email protected] www.avotraining.com
|Hydro training and electrical safety|
In recent years the AVO Training Institute has worked with the following hydro utilities: