Single pole (SP) C curve MCB, 40A & 63A — ISI-marked to IS/IEC 60898-1, 10 kA breaking capacity, for overload and short-circuit protection.
- ISI-marked, made to IS/IEC 60898-1.
- 10,000 A (10 kA) rated short-circuit breaking capacity.
- C curve — suits mixed and inductive loads such as ACs, motors, pumps and fans.
- Protects against overload (thermal) and short circuit (magnetic), with a trip-free mechanism.
- ON/OFF contact-position window shows the state at a glance.
- 1 module wide; snaps onto a standard 35 mm DIN rail.
- Made in India.
A miniature circuit breaker (MCB) switches a circuit off automatically on an overload or a short circuit, and can be switched back on once the fault is cleared — no fuse wire to replace. This Single Pole (SP) MCB protects the phase conductor of a single-phase circuit; the neutral goes to the neutral link of the distribution board.
The C trip curve trips instantly at 5 to 10 times the rated current, so it rides through the normal starting surge of fans, motors, pumps, ACs and LED drivers while still clearing a short circuit fast.
Ratings in this listing: 40A and 63A — choose the rating from the options.
Where to use it
- Final circuits in a home or shop distribution board — lights, fans and sockets.
- Separate protection for each room or each appliance circuit.
How to install
- Switch off the supply at the main switch before working on the board.
- Snap the MCB onto the 35 mm DIN rail and tighten the terminals firmly on the correct cable size.
- Connect the supply (line) and the load to the terminals marked on the MCB.
- Fit it on the phase conductor only — never switch the neutral with a single pole device.
Electrical work should be done by a licensed electrician. For AC circuits only — solar panel and battery (DC) circuits need DC-rated MCBs.
Frequently asked questions
- When do I use a single pole MCB?
- For single-phase final circuits in a distribution board — lighting, fan and socket circuits — where the neutral is taken from the neutral link.
- What is a C curve MCB?
- A C curve MCB trips instantly at 5–10 times its rated current. It suits mixed and inductive loads — ACs, motors, pumps and fans — whose starting surge could nuisance-trip a B curve MCB.
- What does 10 kA breaking capacity mean?
- The MCB can safely interrupt a short-circuit current of up to 10,000 amperes — a comfortable margin for homes, shops and offices.
- Which MCB rating do I need?
- Typically 6A–10A for lights and fans, 16A for socket circuits and geysers up to 3 kW, 16A–20A for a 1.5 ton AC, 20A–25A for a 2 ton AC, 32A for sub-mains, and 40A–63A for main incomers. The MCB must never be rated above what the cable can carry.
- Is an MCB the same as an isolator or RCCB?
- No. An MCB trips on overload and short circuit. An isolator only switches the supply on and off and does not trip. An RCCB trips on earth leakage to protect people from electric shock — homes need one of 30 mA or less in addition to MCBs.
- Why does an MCB trip more often on hot days?
- MCBs are calibrated at 30 °C. In a hot distribution board they carry slightly less current, so keep some margin between the running load and the rating — but never fit a bigger MCB than the cable allows.
Buy ISI-marked single pole C curve MCBs online from Electric Market, Chennai. For panel builders, contractors and bulk orders, contact us for a quote.