What is the role of a voltage tap in a CP system?

In a cathodic protection (CP) system, the role of a voltage tap is primarily to measure the voltage across different points in the system. This measurement is crucial for assessing the potential of the protected structure and ensuring that the cathodic protection is working effectively. The voltage measurements can indicate whether the system is providing adequate protection against corrosion, allowing operators to make necessary adjustments to the system to ensure optimal performance.

Having accurate voltage readings helps in monitoring the corrosion activity and understanding the effectiveness of the cathodic protection applied. This can also guide maintenance activities and assess the need for changes in the system setup or the addition of more anodes, for example.

Other options do not accurately reflect the function of a voltage tap in this context. The voltage tap does not serve to control resistance, reduce current flow, or lower electrolyte levels, as its primary focus is on voltage measurements that inform system performance and design adjustments.