40A double pole (DP) MCB-type changeover switch — moves a single-phase load between two supplies, such as mains and a generator or inverter; 240/415 V.
- Switches a single-phase load between two supplies — mains (EB) and a generator, inverter or second supply.
- Double pole: phase and neutral change over together, keeping the two supplies completely separate.
- Marked 240/415 V, 50 Hz and DP 40A on the front.
- Handles joined by a common bar, so both poles always move together.
- A window on each pole shows which line is selected.
- Connection diagram on the front: a common terminal and two changeover terminals for each pole.
- A switch, not a breaker: it does not trip, so each supply needs its own MCB or fuse.
A changeover switch lets a load run from one of two supplies, never both at once, so a generator or inverter cannot feed back into the mains line. This one is built in an MCB-style body that fits the DIN rail of a distribution board or MCB box.
Both poles — phase and neutral — change over together, keeping the neutrals of the two supplies separate. Each pole has a common terminal and two changeover terminals, as the diagram printed on the front shows.
Where to use it
- Single-phase homes and shops with a generator (mains and DG set).
- Whole-house inverter or UPS wiring, or bypassing the inverter for servicing.
- Choosing between two single-phase supplies for essential circuits.
- Pump and office circuits that must run on a standby supply.
How to install
- Switch off and isolate both supplies before starting.
- Snap the changeover onto the DIN rail of the distribution board or MCB box.
- Connect the outgoing load to the common terminals and each supply to its own changeover terminals as the printed diagram shows — phase with phase, neutral with neutral.
- Protect each supply with its own MCB or fuse, and label which line is mains and which is the generator or inverter.
Electrical work should be done by a licensed electrician. Never connect a generator or inverter to house wiring without a changeover switch.
Frequently asked questions
- What is an MCB changeover switch used for?
- To run a load from one of two supplies — typically mains and a generator or inverter — by moving one handle. The load is never connected to both, so the backup supply cannot back-feed the mains line.
- What does "two way" mean here?
- It is the double pole (DP) version: two poles, phase and neutral, for single-phase supplies. The four way version has four poles for three-phase + neutral supplies.
- Does a changeover switch protect my wiring?
- No. It is a switch only — it does not trip on overload, short circuit or earth leakage. Keep an MCB or fuse on each supply and an RCCB for shock protection.
- Which rating do I need?
- At least the rating of the main MCB or fuse of the supplies it switches. This 40A switch suits a single-phase home or shop with a main of up to 40A.
- Is it an automatic changeover?
- No. It is a manual switch: you move the handle when the supply changes. Automatic changeover needs an automatic transfer switch or a changeover contactor panel.
- Can I change over with the load on?
- Switch off heavy loads such as ACs, pumps and geysers first; changing over under heavy load wears the contacts faster.
Buy two way MCB changeover switches online from Electric Market, with delivery across India from our Chennai store. For site, contractor or bulk quantities, contact us for a quote.