1 May 2005

ISA Certified Automation Professional (CAP) Program

This question is from the CAP study guide, Domain II.

Definition: Identify customer requirements and complete high-level analysis of the best way to meet those requirements.

CAP question

According to NFPA 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

CAP answer

The correct answer is D, resetting an emergency stop circuit to initiate a restart.

may10
Source: Rockford Systems
 

The reset of an emergency stop circuit will not initiate a restart; therefore, the answer is not an acceptable emergency operation.

Emergency stop to override all other functions and operations with all modes is an acceptable emergency operation, per NFPA 79 - 9.2.5.4.11.

Emergency switching off initiated by a single human action is an acceptable emergency operation, per NFPA 79 - 9.2.5.4.1.

Using a locally supplied disconnect is an acceptable emergency operation, per NFPA - 10.7.5.1.

Reference: National Fire Protection Association (NFPA). NFPA 79, NFPA. 2002.

Nicholas Sheble (nsheble@isa.org) edits the Certification department. For information about the CAP program, go to www.isa.org/CAP.