Commonly asked questions regarding Electrical Safety Equipment Safety Equipment.
Are safety interlocks important for person protection?
Generally, a safety interlock is associated with operating equipment or processes. Safety interlocks serve multiple purposes and are important for personal protection. They might be used to ensure that a manufacturing process is interrupted when the interlock operates. For instance, an overpressure switch or a high-level switch might be a safety interlock. A safety interlock might be a limit switch installed on a door to ensure that a segment of an operating process is interrupted when a door is opened.
Is a GFCI effective in preventing injuries?
Ground-fault circuit interrupters (GFCI’s) are extremely effective in preventing injuries. These devices sense when current is flowing in an unintended circuit and assumes that the current id through a person’s body. A GFCI limits the amount of current to no more that 6 mili-amperes, which is a level that will not result in electrocution.
What is the role of overcurrent protection?
Overcurrent protection is intended to remove the source of energy any time current exceeds the rating of the circuit. Overcurrent protection does not affect the shock or electrocution hazard. The speed at which an overcurrent device operates is one critical variable of available energy.
Can I substitute a different size fuse?
Like circuit breakers, fuses are tested and rated to clear a known level of overcurrent or fault. A worker may substitute fuses smaller current ratings, provided the interrupting rating of the substitute fuse remains the same. However, larger fuses or fuses with smaller interrupting rating must not be used. Fuses with the same ratings but from different manufacturers must not be mixed in the same circuit.
Is electrical equipment tested in a failure mode?
Electrical equipment that has a third-party label is tested and certified to comply with the requirements of a specific test procedure. However, most third-party testing does not consider arcing fault conditions. Unless the equipment is rated as arc resistant, arcing faults are not considered.
Why is routine opening and closing of circuits an issue?
When rated for the service, disconnecting means may be used to open or close a circuit. If the disconnecting means is not load rated, however, the handle should not be moved while the load is operating. Cable connectors should not be used to open or close a circuit, unless they are rated for the service.
When current is flowing in an electrical circuit, its inductive characteristic will not permit the current to be interrupted instantaneously. Each time a disconnecting means is operated, therefore, an arc occurs. Devices that are rated to open and close under load are designed to minimize the effects of the expected arc. However, the expected arc will damage devices that are not designed to open under load, increasing the chances of failure.