Phoenix Contact 3210230 When using an isolating plug for a terminal block, the voltage and current ratings can be determined by the type of plug used, with specific values given for each. The connection method is typically push-in, while the rated cross-sectional area ranges from 0.14 mm2 to 4 mm2, depending on the specific application requirements. Additionally, mounting options are available in different configurations such as NS 35/7,5 and NS 35/15, and a standard color of gray is commonly used for these isolating plugs.