What measures are used to protect a gauge from excessive pressure?

A shut-off cock is used to protect a gauge from excessive pressure by allowing the operator to isolate the gauge from the system when needed. By closing the shut-off cock, any potential overpressure in the system is prevented from impacting the gauge. This is particularly useful during maintenance or inspection when it's critical to ensure the gauge is not exposed to high-pressure conditions that could lead to damage or inaccurate readings.

When it comes to other measures, while pressure relief valves are designed to relieve excess pressure in a system, they do not specifically protect gauges. A safety trap might be used to collect condensate or drain processes, and a flow restrictor typically regulates flow rather than providing direct protection to a gauge. Thus, the shut-off cock provides a direct means to safeguard the gauge itself, making it the relevant option for this question.