It handles data exchange between the RCD and the ETU, so the breaker's trip unit sees the residual current signal and can coordinate ground-fault protection with overload and short-circuit curves. This is a spare part, not a field-assembled harness — one cable serves one breaker directly.
What the dimensions mean for panel fit
At 124 mm deep, 90 mm wide, and 41 mm tall, this cable's plug body fits into the accessory slot on the side of a 3VA2 breaker. The 90 mm width matches the standard 3VA frame width, so it does not overhang the breaker envelope — no extra DIN-rail space needed beyond what the breaker already occupies. The 41 mm height keeps it clear of adjacent pole barriers and arc chambers inside the panel.
What it does — and what it does not do
This cable is purpose-built for the RCD820 and 3VA2 combination. It enables communication with residual current equipment and data exchange with the electronic tripping unit. It does not communicate with a motor drive — that is a separate function handled by other SENTRON communication modules. The connection is removable/pluggable, so it can be disconnected for breaker maintenance or replacement without cutting wires.