Double pole (DP) RCCB, 40A, 30 mA — cuts a single-phase supply on earth leakage to protect people from electric shock; 240 V AC.
- Trips on an earth leakage of 30 mA — the sensitivity used to protect people from electric shock.
- Double pole (phase and neutral), for single-phase 240 V AC, 50 Hz supplies.
- Rated current 40A; making and breaking capacity (Im) 500 A, as printed.
- Test button marked Test Monthly — press it once a month; the RCCB must trip.
- ISI-marked to IS/IEC 61008-1, as printed on the unit pictured.
- Does not trip on overload or short circuit — always install it with an MCB or fuse.
- 2 modules wide; snaps onto a standard 35 mm DIN rail.
An RCCB (residual current circuit breaker, often still called an ELCB) compares the current going out on the phase and neutral with the current coming back, and switches the circuit off if part of it leaks to earth — through damaged insulation, a faulty appliance or a person.
At 30 mA it protects people: if someone touches a live part, or a faulty appliance leaks current through its metal body, it cuts the supply within a fraction of a second. The CEA safety regulations of 2023 require a residual current device of 30 mA or less in homes.
It does not trip on overload or short circuit, so it always works with MCBs or fuses. This 40A model suits a circuit protected by an MCB of 40A or less.
Which RCCB do I need
- DP for single-phase supplies; FP for three-phase + neutral supplies.
- 30 mA: protects people — homes, bathrooms and socket circuits.
- 100 mA: equipment protection and upstream RCCBs.
- 300 mA: fire protection at the main incomer.
Where to use it
- Main RCCB of a single-phase home or flat, after the main MCB or isolator.
- Bathroom, geyser, washing-machine and kitchen circuits.
- Socket circuits in homes, schools, clinics and shops.
- Terrace, garden and outdoor-light circuits.
How to install
- Switch off the main supply, confirm the board is dead, and snap the RCCB onto the DIN rail after the main MCB or isolator.
- Connect the supply to the LINE side and the outgoing circuits to the LOAD side, with the phase and neutral on their marked terminals.
- Take every neutral of the protected circuits through the RCCB, and never join neutral and earth after it — either mistake makes it trip.
- Switch on, press the test button (the RCCB must trip), reset it and label the board.
Electrical work should be done by a licensed electrician. For AC circuits only.
Frequently asked questions
- Do I need an RCCB if I already have MCBs?
- Yes. MCBs trip on overload and short circuit; an RCCB trips on earth leakage — current escaping to earth through a fault or a person. A safe board needs both.
- Why 30 mA?
- 30 mA is the sensitivity used to protect people against electric shock, and the CEA safety regulations of 2023 require a residual current device of 30 mA or less in homes. 100 mA and 300 mA RCCBs protect equipment and guard against fire, not people.
- Which current rating do I need?
- One at or above the MCB or fuse that protects the RCCB. This 40A model suits a main MCB of up to 40A — typically the main of most homes, flats and small shops.
- Why does my RCCB keep tripping?
- Usually a real leak: a faulty geyser element, washing machine or pump, damp wiring, or a neutral touching earth or shared with a circuit outside the RCCB. Switch off all MCBs, reset the RCCB, then switch the MCBs on one by one to find the faulty circuit.
- How do I test an RCCB?
- Press the test button once a month with the power on. It should trip at once; switch it back on. If it does not trip, have it checked by an electrician.
Buy double pole 30 mA RCCBs online from Electric Market, Chennai. For site, contractor or bulk quantities, contact us for a quote.