This is a continuation of my last blog on normal operating conditions. Safe use of equipment under NFPA 70E is based on the equipment meeting these conditions. Although the conditions are a starting point for all electrical work, the conditions are necessary before an employee operates the equipment for its normal function. Properly installed, properly maintained and closed doors were addressed in the previous blog.
Covers in place and secure – This takes a little judgement of the operator. Remember that this is also in the section addressing normal operation. Using the example of the access door for the panelboard circuit breaker, the hinged door is on a bolted cover that is intended to stay in place when operating the breaker. You must make sure that any equipment covers are properly secured. This will require proper training of the person interacting with the equipment. If the covers are absent or unsecured, your employee is potentially at risk of an injury if they attempt normal operation of that equipment. This safety issue is not addressing the tasks that require an energized work permit. This covers the person operating a HID breaker to turn the factory lights on each morning, for example.
No signs of impending failure – This is a tough one. Typically the employer/owner is not aware of the condition of individual equipment in their facility. The burden of determining this is often the responsibility of the person (think AHJ) interacting with the equipment since conditions can change on a daily basis. This involves training that person to understand the potential failure modes and to identify signs of the impending failure of the equipment. These signs vary greatly by the type of electrical equipment. The smell of ozone, presence of smoke, sound of arcing, visible damage, or warning lights are all possible indication of potential equipment failure. If any of the signs are present, that person is potentially putting themselves at risk of an injury if they attempt normal operation of that equipment. This safety issue is not addressing the tasks that require an energized work permit. This covers the person operating a HID breaker to turn the factory lights on each morning, for example.
Instructions – Regardless of the equipment meeting the normal operating conditions, for an employee to safely interact with equipment they must understand the conditions, methods, functions and sequences for safely operating the equipment. Equipment typically is supplied with manufacturer’s operating instructions. If the equipment is listed, these instructions typically include the specifics necessary to operate the equipment within the parameters of that listing. Operating equipment contrary to the instructions puts the employee at risk of an injury whenever they attempt to operate of that equipment. This covers the person operating any electrical equipment including proprietary or production line equipment.
There is no reason to believe that normal operation of equipment meeting these conditions inherently presents a unacceptable risk of injury to a person. No interaction with equipment would be permitted if it did. A computer, light switch or elevator would be a hazard with an unacceptable risk level. Society has come to terms with the concept that normal operation of equipment does not pose an unacceptable risk of injury to persons under these conditions. In your facility, you are responsible for assuring that the conditions which permit normal operation have been meet before allowing your employees to interact with your equipment.
Next time: Does normal operation cover everything that a manufacturer claims the equipment can do?