DPST vs DPDT Rocker Switches: Pins, Ratings and Waterproofing

DPST or DPDT — count the pins

The quickest way to identify what you need is to count the pins on the back of the old switch.

"Double pole" means it switches both live and neutral together — the equipment is properly isolated when it's off, not just interrupted on one line. That is why commercial equipment uses double pole.

They are not interchangeable. A 4-pin DPST cannot do the on/off/on job of a 6-pin DPDT — there is physically nowhere for the second circuit to connect.

What does 30A 250V mean, and why does it matter?

It is the maximum the switch is rated to carry: 30 amps at 250 volts.

Never fit a switch rated below what the appliance draws. An under-rated switch overheats, the contacts weld or burn, and the switch fails — sometimes dangerously. The rating is not a suggestion; it is the whole specification.

Fitting a higher-rated switch than needed is fine — the load simply never approaches its limit.

Why waterproof?

Because it's a commercial kitchen. Switches get splashed, steamed, wiped down with wet cloths and hosed near.

Moisture in a switch is what causes:

• Intermittent operation — works sometimes, not others.
• Corroded contacts — increasing resistance, heat, and eventual failure.
• Tracking and shorts — a genuine safety issue in a wet environment.

A waterproof switch is sealed against exactly this. In a kitchen it's not an upgrade — it's the correct part.

What is the LED for?

The illuminated LED tells you at a glance that the circuit is live. In a busy kitchen, on a panel of identical black switches, that visual confirmation matters — both for operation and for safety.

We stock LEDs in black, blue, yellow, red and green (all £14.99), so you can colour-code by function. Red for the heat, green for the fan, and anyone can read the panel without hunting for labels that have long since worn off.

My switch has stopped working — is it definitely the switch?

Check these before replacing it:

• Is there power to the switch at all? A dead circuit upstream looks exactly like a dead switch.
• Are the terminals corroded or the spades loose? Very common in a wet kitchen — and it's the connection, not the switch.
• Does the rocker feel mushy or stay depressed? The mechanism has failed. Replace it.
• Does it work intermittently, or only when pressed hard? The contacts are burnt or corroded. Replace it — an intermittent switch on a heating circuit is not something to live with.
• Is the LED out but the equipment still runs? Just the LED has failed. The switch still works, but you have lost your visual confirmation.

Fitting

1. Isolate the equipment at the mains and lock it off. Not just switched off — isolated.
2. Photograph the wiring before you disconnect anything. A 6-pin DPDT is very easy to get wrong from memory.
3. Note which spade goes to which pin.
4. Fit the new switch, matching the pin layout exactly.
5. Push the spades fully home — a loose spade at 30A generates heat.
6. Check the seal seats properly in the panel cut-out. A waterproof switch that isn't sealed into the panel isn't waterproof.

Electrical work on commercial catering equipment should be carried out by a qualified electrician. This is mains voltage at high current in a wet environment.

Frequently asked questions

How do I know if I need DPST or DPDT?

Count the pins on the old switch. 4 pins = DPST. 6 pins = DPDT. Also look at the action: if the rocker has a middle-off with two live positions, it's DPDT.

Can I fit a higher amp switch?

Yes — higher is safe. Lower is not. Never fit a switch rated below the load.

My switch keeps failing. Why?

Usually one of three things: it's under-rated for the load, moisture is getting in, or the spade connections are loose and generating heat. Fix the cause or the new switch will go the same way.

Does the LED colour affect anything electrically?

No — it's purely visual. Use it to colour-code your panel by function.

How fast can I get one?

UK stock, £14.99. Order before 10am for next-day delivery, free over £25. Call 073 8051 5838 with a photo of the old switch and we'll match the pin layout.

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