Current drainage box CAA / CSC

Current drainage box CAA / CSC: overview

The current drainage box is installed at each anode bed (CAA) or for the return of protection current to the rectifier negative (CSC). It connects the anode or structure feeder cables to the positive or negative pole of the converter (or transformer rectifier) and allows current measurements.

Weatherproof, in steel or stainless steel (IP55/IK10, RAL 7032), it is available in 40×40×20 cm or 60×40×40 cm. Each box features a bakelite insulating plate (5 mm thick), a copper link bar, adjustable RBCA-type resistors (e.g. 10 Ω/100 W), 10 A/100 mV ammeter shunts, removable copper sectioning bars, crimp lugs and heat-shrink identification sleeves. It is supplied with a 1.40 m Ø3" galvanised steel support tube.

Its place in the system

Between the transformer-rectifier and the structure, current does not flow through a single cable: it is shared between several anodes, or returns from several points on the structure. The drainage box organises these circuits. Each one has its own shunt, to measure the current it carries, and its own adjustable resistor, to balance its output.

CAA or CSC?

The CAA is placed at the anode field and shares current between anodes; the CSC is placed on the return, on the structure side. Removable links allow a circuit to be isolated for measurement or maintenance without shutting down the rest of the installation.

Current drainage box CAA / CSC: technical specifications

Current drainage box CAA / CSC: documentation