Being Safe When Working With Electrical Transformers
In accordance to the National Fire Protection Association (NFPA) all electrical wiring and equipment must be in accordance with NFPA 70. Electricity is hazardous and all employees working with transformers are subject to protection. This is unless it is an existing installation which can be allowed to continue in service based on authorization of the jurisdiction in power over it.
In this article we will review basic information within NFPA 70 regarding transformers.
Transformer rooms that are made from fire-resistant construction with a minimum fire rating of an hour needs to be used with any individual, dry-type transformers of more than 112 ½ kVA rating. Below this there isn’t specific installation requirements for the room in which the transformer is located. Ones rated over thirty five hundred volts need to be installed within a vault with three hours fire-resistance.
Doorways leading into a vault from the interior of the building must have doors that are not only tight fitting but also have a minimum fire rating of three hours. One exception is when the transformers are protected by automatic sprinklers, water sprayers or carbon dioxide in which a one hour rating is sufficient.
The NFPA 70E addresses safety standards in electrical safety. These requirements are in place to protect all employees who install, maintain, and repair electrical systems and their components. It recognizes the dangers associated with electrical energy. These guidelines are in place to prevent against injury or death.
In order to comply with the NFPA 70E all employees working and operating electrical equipment above 50V must wear arc-flash protective gear. Arc-flash is an electrical current passes through the air when the insulation between electrified conductors can no longer withstand the voltage being applied. Even a flash that lasts under a second can be severe, leading to a fatality.
In order to establish compliance with the NFPA 70E there is a checklist that lays out both short-term and long-term actions to take. Some of them are listed below:
Maintenance mechanics, facility repair workers and electricians are not allowed to work on hot or live equipment while wearing all cotton apparel.
Equipment should be de-energized as much as possible before work is performed.
Hazard warning labels should be placed on all electrical equipment.
Workers should be trained in arc-flash hazards.
Logout/Tagout (LOTO) procedures need to be updated and reviewed often to be sure all control panels are included.
LOTO training needs to be constantly assessed to ensure employees are trained properly. If there is an issue they should be retrained.
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