What is the time limit for the highest voltage to be restricted inside the equipment post rapid shutdown initiation?

The correct choice is based on the requirements outlined in NEC Article 690. During a rapid shutdown initiated in photovoltaic (PV) systems, a critical safety measure is to limit the maximum voltage present at the equipment to ensure the safety of firefighters and first responders. The National Electrical Code mandates that this voltage must be restricted within a specified time frame.

According to the NEC, the highest voltage must be reduced to a safe level within 30 seconds of the shutdown being triggered. This provision is in place to facilitate a safer environment during emergency situations, thereby reducing the risk of electrical shock for anyone handling the equipment following a rapid shutdown.

Therefore, the time limit of 30 seconds is vital for ensuring that the system becomes non-energized quickly, aligning with safety protocols and improving emergency response efforts. Other time frames such as 10 seconds, 1 minute, or 5 minutes do not meet the NEC requirements for the rapid shutdown, which is specifically stated as 30 seconds for the voltage to be reduced.