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Today's automation industry quiz question comes from the ISA Certified Automation Professional certification program. ISA CAP certification provides a non-biased, third-party, objective assessment and confirmation of an automation professional's skills. The CAP exam is focused on direction, definition, design, development/application, deployment, documentation, and support of systems, software, and equipment used in control systems, manufacturing information systems, systems integration, and operational consulting. Click this link for information about the CAP program. The following question comes from the CAP study guide, Performance Domain II, Definition: Identify customer requirements and complete high-level analysis of the best way to meet those requirements.
According to NFPA (National Fire Protection Association) Electrical Standards for Industrial Machinery, which of the following actions is NOT acceptable for emergency operations?
a) using a locally supplied disconnect
b) using an emergency stop to override all other functions and operations with all modes
c) using an emergency switch off initiated by a single human action
d) resetting an emergency stop circuit to initiate a restart
e) none of the above
The reset of an emergency stop circuit will not initiate a restart; therefore, the answer is not an acceptable emergency operation and is the correct answer.
Emergency stop to override all other functions and operations with all modes is an acceptable emergency operation, per NFPA 79 - 184.108.40.206.11.
Emergency switching off initiated by a single human action is an acceptable emergency operation, per NFPA 79 - 220.127.116.11.1.
Using a locally supplied disconnect is an acceptable emergency operation, per NFPA - 10.7.5.1.
The correct answer is D, resetting an emergency stop circuit to initiate a restart.
Reference: NFPA. NFPA 79, NFPA.