Electrical Safety Series
Electrical safety series
This section is mainly about LOTO, which you should be familiar with if you have run a similar program. It's just that in NFPA 70E, in addition to requiring employers to establish LOTO procedures, there are other specific requirements, and we'll focus on some of the more interesting or easily overlooked ones.
The employer's responsibilities include ensuring that the equipment provided is in lockable condition. Providing the equipment neceassary to execute lockout/tagout procedures. Therefore, as EHS, we should give appropriate Suggestions to help improve the equipment and facilities that do not have the function of locking and listing. Of course, we can also equip auxiliary locking tools to achieve the purpose of locking.
#2 lock and tag the circuit breaker that can achieve physical partition, instead of using emergency button or select switch as the locking point. LOTO shall be installed only on circuit disconnecting means. The Control devices, to as push buttons - or the selector switches, shall not be, informs the as the primary isolating device. Note: In the general LOTO program, some PLC functions can be used as energy locking points for certain operations, which is not inconsistent with this article, because the overall PL level of the equipment can be used to lock to prevent accidental start of the equipment; What NFPA 70E is saying is to eliminate shock hazard, not to prevent the device from accidentally starting, but to completely prevent electric shock injury, so it must be completely cut off, not logically locked.
The lockout device shall include a method of identifying The individual who identifies The lockout device. In other words, The lockout device shall contain The information of The person who identifies The lockout device.
This section has a clear definition of the release of stored energy. What is interesting is that it not only refers to the capacitance related to electricity, but also refers to the release of hydraulic energy and potential energy unrelated to electric shock.
#5 in the LOTO chapter, for the electric test, it is emphasized again that the test should be conducted on the known voltage before and after each test, so as to ensure that the test tool is always in good condition. Test instrument to be used, the required PPE, and the person who will use it to verify proper operation of the Test instrument on a known voltage source before and after use.
#6 this chapter focuses on the specific steps to establish and verify Safe working conditions of electricity, and emphasizes that the steps should be followed to ensure Safe Work conditions.
Ensure that all power lines have been cut off and can be confirmed on site by reference to the latest circuit diagram;
After the load is opened and closed, open the disconnect device of each power supply;
Visually check that all disconnecting devices have been completely and completely disconnected;
Release stored electrical energy;
To release or lock mechanical energy;
Implement locking and listing according to the procedure;
Use instruments to test each phase of the power supply;
Ground if necessary. (this is common in switchboards)