Pin busbar, 10mm2 Connection: 3-phase/+ 8x phase touch-safe for 1FI, 4-pole, NLI+8LS, 1-pole. Pin busbar SENTRON 5ST3 as an additional component for residual current devices and circuit breakers. These additional components can be installed universally. They are easy and convenient to install and connect. Thanks to the standard touch protection, safety during installation is reliably guaranteed. Optimum technology for your safety - only from Siemens.