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.
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