Electrical Safety for Broadcasters
The traditional model for electrical safety at broadcast sites (and transmitter manufacturing facilities) was based on common sense and the words of wisdom passed from senior engineers to their juniors. For many of us who have spent part of our careers working in this type of safety environment, we have seen or experienced near misses where injuries might have occurred, and some of us know of cases where there was loss of life.
Safety Program Elements
Today, most companies as well as federal, state or provincial law require us to have a safety program composed of multiple elements:
- A clear system of responsibilities for managers, supervisors and employees
- A joint safety committee with both managers and employees involved
- Orientation, training and a qualification process for employees
- Safe work policies, procedures and protective equipment
- Incident reporting and investigation
- Emergency response and first aid
Any organization which implements these elements in a meaningful way will benefit from a substantial reduction or elimination of injury rates. This is not only a legal requirement; it is simply the right thing to do. For broadcast sites, electrical safety is a primary hazard that must be managed.
In North America, we are fortunate to have two excellent reference documents, which are also legal requirements in many places:
- In the U.S., NFPA 70e: Standard for Electrical Safety in the Workplace®
- In Canada, CSA Z462-15 Workplace Electrical Safety.
These documents contain all the necessary elements of an effective electrical safety program.
In addition to the elements mentioned above, they contain specifics on electrical safety including:
- Specifics on who is qualified to do electrical work
- The use of job briefings
- How live work is managed using work permits
- How contract workers will be managed
- How workers assess electrical hazards, chose appropriate personal protective equipment and apply safe work practice
Implementing an Electrical Safety Program
For most engineers or technical staff learning about modern electrical safety practices for the first time, you will need to become familiar with these key concepts:
- Arc Flash Hazard: High-energy AC circuits typical of those used to feed transmitters can release dangerous amounts of energy in the event of a fault, typically caused inadvertently when a worker is present. Reducing the risk that arc flash presents to workers requires that a professional engineer is contracted to analyse the electrical equipment at a given site. The arc flash hazard analysis is then used by workers to determine the “Incident Energy” which may be released during a fault and the “Arc Flash Boundary” inside of which the risk of injury is high.
- Arc Rated Personal Protective Equipment: To safely work on high-energy circuits, workers need protective equipment which has been tested and verified to protect the worker in the event of an arc flash event. This PPE will cover all parts of the body and have an energy rating in either Calories or Joules per square centimeter.
- Qualified Worker: Specific details on what is required for a worker to be qualified to work safely on electrical systems.
- Electrically Safe Work Condition: The process by which conductors or circuits have been disconnected from the supply, locked out and tested to ensure they are safe to be worked on.
- Limited Approach Boundary: An approach limit within which a shock hazard exists. This is generally used by the qualified electrical worker to protect others at the work site.
- Prohibited Approach Boundary: An approach limit within which there is an increased risk of shock.
- Electrical Safety Gloves: Electrical workers require rubber insulating gloves and other equipment that protect against electric shock. They also require the training to ensure they know when to use them.
The first step toward implementing an electrical safety program is to review and update your policy. This can be done using one of the above mentioned standards as the key reference, while verifying that your local laws are also satisfied. Often, changing behaviors can be a challenging process especially where experienced employees are involved. Having key employees and supervisors involved at the ground floor with the policy process is a great opportunity to educate and build a sense of positive change within the group.
Arc Flash Study
In addition to the first step of reviewing policy, there are several other important aspects. Any facility will require an arc flash study. This study is relatively detailed and will require specific knowledge of your electrical system as well as information from your electrical utility. Typically, as in Nautel’s case, this work is outsourced to a qualified professional engineer. The study will require that an electrical system schematic be generated if not already available. Further detail such as lengths of electrical interconnections, types of fuses and circuit breakers and transformer details will be added to the schematic. The results of the arc flash analysis are then added to equipment labels so that workers have the information when needed while working with the electrical system. Personal protective equipment will need to be reviewed. Generally you will require electrical gloves and arc flash protective equipment for employees.
With the basic tools in place (policy, PPE and labelling of hazards) the focus should shift to ensuring employees are trained. A training package typically might consist of a deck of PowerPoint slides as well as a written test for employee’s files. Again, the key employees involved since the beginning of the project will be able to deliver the training in an effective way.
Organizations that invest the effort in an effective safety program will reap multiple benefits. In addition to having low injury rates, safe and healthy workplaces are better places to work, improving employee satisfaction and retention as well as being more productive and producing a better quality product.