16A 240 V SPN main switch — a compact rewireable switch fuse unit for single-phase supplies, with a side handle and ON/OFF marked label.
- Single pole and neutral (SPN) switch fuse unit for single-phase 240 V supplies.
- Rated 16A at 240 V, as printed on the front label.
- Rewireable fuse carrier — the fuse wire is the only protection the unit gives.
- Side handle: ON up, OFF down, as marked on the label.
- White metal enclosure with a hinged door and a knob fastener.
- Cable entry at the top of the enclosure.
- No trip and no earth-leakage protection — add a 30 mA RCCB for shock protection.
An SPN main switch — also called a switch fuse unit or SFU — combines an on/off switch and a rewireable fuse in one small enclosure. SPN means single pole and neutral: the phase goes through the switch and the fuse, and the neutral through a neutral link.
It protects only through its fuse wire, which melts on a heavy overload or short circuit and must then be replaced with wire of the correct rating. It does not trip like an MCB and gives no protection against earth leakage or electric shock, so pair it with a 30 mA RCCB.
At 16A it suits small single-phase supplies and single loads. For a bigger single-phase main, see our 32A 240V DP main switch; for three-phase supplies, our TPN main switches.
Where to use it
- Main switch of a small single-phase home, room, shop or kiosk.
- Local switch and fuse for a single-phase pump, motor, geyser or machine.
- Temporary site and event supplies.
- Replacing an old 16A SPN main switch like for like.
How to install
- Isolate the incoming supply (the supply company's cut-out or the upstream switch) before working.
- Fix the unit upright on a wall or board, with room for the side handle to move.
- Bring the phase to the switch and fuse, and the neutral to the neutral link, as marked inside the unit.
- Fit fuse wire of the correct rating, earth the enclosure and close the door before switching on.
Electrical work should be done by a licensed electrician. Re-wire a blown fuse only with the supply off, using fuse wire of the correct rating — never thicker wire or copper strip.
Frequently asked questions
- What is an SPN main switch?
- A switch fuse unit for single-phase supplies. SPN means single pole and neutral: the phase goes through the switch and a rewireable fuse, the neutral through a neutral link. The side handle switches the supply on and off.
- Does it trip like an MCB?
- No. It has no trip mechanism; the fuse wire melts on a heavy overload or short circuit and must then be replaced. It gives no protection against earth leakage or shock — add a 30 mA RCCB.
- What fuse wire should I use?
- Wire of the rating the circuit needs, never above 16A for this switch, as your electrician advises. Thicker wire, doubled wire or copper strips will not blow on a fault and can let the cable overheat.
- Should the neutral have a fuse?
- No. Indian safety regulations do not allow a fuse in the neutral conductor, which is why the neutral runs through a solid link.
- SPN or DP main switch — which one?
- Both are for single-phase 240 V supplies. SPN has a fused phase and a neutral link; a DP switch breaks both lines together. This 16A SPN suits small loads; for bigger ones see our 32A DP main switch.
Buy 16A SPN main switches online from Electric Market, Chennai. For site, contractor or bulk quantities, contact us for a quote.