All means of interconnecting equipment shall be monitored so that a single open or a single ground fault condition is indicated within how many seconds?

• A. 200
• B. 10
• C. 30
• D. 90

Answer: (A)

The idea is to ensure that any fault in the means of interconnecting equipment is noticed quickly enough to take action before it causes more problems, but not so fast that normal variations trigger false alarms. The specification requires that a single open condition or a single ground fault be indicated within 200 seconds. That time frame gives a reliable prompt indication while allowing for normal transient conditions to settle in, balancing sensitivity with practicality for maintenance and safety. The other options are less appropriate because they either demand too rapid an indication, which can cause nuisance alarms, or are too slow to catch faults in a timely manner. If a conductor opens or a ground fault occurs, the monitoring system will alert within about three minutes, prompting corrective steps before equipment is damaged or safety is compromised.