ABB S202-C20 Two-pole Miniature Circuit Breaker, C 20 A

S202-C20 (order code 2CDS252001R0204) is the two-pole 20 A C-curve member of the ABB S200 miniature circuit breaker family. A thermal element protects the cable against overload and an electromagnetic element against short circuit; the C characteristic leaves room for lamp, transformer and small motor inrush. Its 6 kA capacity under IEC/EN 60898-1 suits a 20 A two-pole branch to sockets or a small motor, among other board circuits.

More low-voltage protection devices are listed under circuit breakers, for example the SACE Tmax XT moulded case breaker range for higher currents.

Technical specifications

Thermal and magnetic behaviour at 20 A

The C curve trips instantly between 5 and 10 times In, which for 20 A means 100 A to 200 A, and at 5 x In the delay is 0.1 to 15 s. Thermally, no trip occurs below 22.6 A (1.13 x In) for an hour and a trip is required within an hour at 29 A (1.45 x In), at the 30 C reference temperature. The permitted operating current falls to 18.9 A at 40 C, 17.6 A at 50 C and 16.3 A at 60 C according to the ABB table. Grouping matters too, with factors of 0.9, 0.8 and 0.75 for two or three, four or five and six or more adjacent loaded devices.

Two-pole duty and add-ons

A 2P breaker interrupts two conductors in one operation. Ratings are 400 V AC (IEC/EN 60898-1), 440 V AC (IEC/EN 60947-2) and 125 V DC. Fitted options include auxiliary and signal contacts, shunt trip, undervoltage release, motor operator and DDA 200 residual-current block. The body needs 35 mm of DIN rail.

Reading the type code

S202-C20 reads as an S200 breaker with 2 poles, characteristic C and 20 A. The ordering reference for this type is 2CDS252001R0204. Before an order goes out, match the pole count, curve, current, voltage and fault level against the installation drawings and decide about accessories.

Key features of the S202-C20

• Dual standard rating: rated to both IEC/EN 60898-1 for installation use and IEC/EN 60947-2 for industrial use, plus UL 1077 as a supplementary protector.
• High service breaking capacity: Ics of 7.5 kA under IEC/EN 60947-2 means the breaker remains serviceable after clearing a fault at that level.
• Compact 2-module width: 35 mm on the DIN rail, fitting standard distribution boards and consumer units.
• Accessory-ready: auxiliary and signal contacts, shunt trip, undervoltage release, motor operator and RCD blocks from the System pro M compact range can be attached.

Why a C curve at 20 A

Curve selection balances nuisance tripping against protection. A B-curve breaker trips magnetically at 3 to 5 times In and suits purely resistive loads and long cable runs where fault current is low. The C curve, at 5 to 10 times In, tolerates the inrush of transformers, LED drivers, fluorescent ballasts and small motors, which is why it is the common general-purpose choice in commercial and light industrial boards. For loads with very high inrush, such as large transformers or motors started direct on line, a D or K characteristic may be more appropriate.

When using a C curve, check that the earth-fault loop impedance of the circuit is low enough for the prospective fault current to exceed 10 × In, that is 200 A, so that the instantaneous trip operates within the disconnection time required by the wiring regulations.

Applying the derating factors

The ABB table shows how much the permitted current falls as enclosure temperature rises. Inside a sealed outdoor distribution board in summer, internal temperatures of 50 °C or more are not unusual, and at that point the breaker carries only about 17.6 A continuously. Combining this with the grouping factor for adjacent loaded devices can reduce the usable current further. For circuits that run close to 20 A, consider a larger enclosure, ventilation, spacing between devices or a higher rating coordinated with a larger cable.

Selecting between 1P, 1P+N and 2P

Installation notes

• Tighten terminals to 2.8 Nm and use conductors no larger than 35 mm².
• Busbar supply from the top or bottom is possible within the System pro M compact range; check the accessory catalogue for compatible busbars.
• Install behind a cover to achieve IP40 on the front face.
• Verify selectivity with the upstream breaker or fuse where continuity of supply matters.

Common uses in Oman and the GCC

Two-pole 20 A breakers are widely used in villas, offices, retail fit-outs and site cabins for air-conditioner circuits, water heaters and socket groups, as well as in control panels for small motor and heater circuits. High ambient temperatures in the region make the derating table particularly relevant during board design.

Information for your RFQ

• Type S202-C20 and order code 2CDS252001R0204, with quantity.
• Any accessories required, such as auxiliary contacts or an RCD block.
• Project name and required certificates or test reports.

Documents and quotation

The hosted ABB data sheet describes the S 200 and S 200 M MCBs and lists ratings, tripping curves, derating factors, accessories and dimensions. Ask Seven Star LLC, an independent supplier in Muscat, for a quotation stating type and quantity. This page shows no price or stock level; confirm the specification before you order.