Mini Changeover Relay — 12V 40A/30A 5-Pin Resistor Protected

Q: What does 'changeover' mean on a relay?
A changeover relay has two switched circuits sharing one trigger. One contact is normally open (N/O) and closes when the coil energises; the other is normally closed (N/C) and opens when the coil energises. Flip the trigger, both circuits swap state at once.

Q: What's the difference between N/O and N/C contacts?
N/O (normally open) sits open until the coil energises, then closes to let current flow. Use it for loads that stay off until triggered: driving lights, horn, a radiator fan on demand. N/C (normally closed) sits closed and lets current flow until the coil energises, then opens. Use it for loads that stay on until triggered: an interlock that cuts an accessory when another system turns on.

Q: Why is the N/O rated higher than the N/C?
Contact pressure. Mini changeover relays spring the common pin against the N/C contact at rest, which is a lighter pressure than the magnetic pull that closes the N/O when energised. More pressure means lower resistance and higher current capacity. 40A N/O and 30A N/C is the industry norm across mini changeover relays.

Q: What does '280 Series' mean?
It's the pin spacing standard for mini ISO automotive relays. Pins are 6.3mm wide spade terminals on the 280 pattern layout. Any socket or wiring harness labelled '5-pin mini relay' or '280 Series' will seat this relay.

Q: What does 'resistor protected' do?
There's a resistor wired across the coil. When the coil switches off, the collapsing magnetic field would otherwise spike several hundred volts back down the trigger wire; the resistor bleeds that energy off harmlessly. Protects any ECU, body computer or trigger module upstream.

Q: Can I use this on a 24V system?
No. The coil is wound for 12V and will burn out on 24V within minutes. Use a 24V-rated relay for 24V trucks and gear.

Q: What's the difference between a mini and a micro relay?
Mini relays are the larger industry-standard 280 Series body (~28mm per side, 6.3mm pins). Micro relays are smaller 180 Series (~15mm per side, 2.8mm pins) and usually sit in modern vehicle fuse boxes. The two are not interchangeable — different socket, different pin pattern.

Q: Do I need a separate relay socket?
If your wiring loom already has a 5-pin mini relay socket, the relay plugs straight in. If you're wiring from scratch, you'll want a mini relay base with crimp terminals — we sell one that fits this relay (linked above).

Q: How much current does the coil itself draw?
Around 0.15A at 12V (roughly 1.8W), which is low enough for any dash switch or ECU output to drive without a secondary relay or load resistor.

Q: What size fuse should protect the switched circuit?
Fuse at or just above the actual load, not at the relay's maximum rating. A pair of 55W driving lights draws about 10A, so fuse at 15A. A 20A radiator fan fuses at 25A. The relay's 40A ceiling is the limit, not the recommended fuse size.

Q: Can this run my winch or inverter?
No. Winches pull 200–500A under load and inverters above 1000W draw 80A+ — both far beyond this relay's 40A ceiling. Use a heavy-duty 80A+ relay or a solenoid rated for the actual load.

Q: How long will it last?
Rated for 500,000 switching cycles at full load, which is well over a decade of daily switching in typical automotive use. Cycle life drops as the load approaches the rated maximum — running at 20A gives roughly double the cycles of running at 40A.