Wiring a PTC element is simpler than a lot of people expect — the tricky part is usually protecting the rest of the circuit, not the element itself.

The basics

• No polarity to worry about. A PTC ceramic element is a resistor, not a diode — current can flow either direction, so there’s no “wrong way” to connect the two leads.
• Series or parallel, depending on your goal. Wiring multiple elements in series divides voltage across them; parallel keeps full voltage across each but increases total current draw.
• Match wire gauge to current draw. Calculate expected current from the element’s rated wattage and voltage (I = P/V) and size wiring accordingly.

Series vs. parallel: which to choose

Wiring elements in series is useful when you want to distribute a fixed supply voltage across multiple elements, effectively lowering the voltage (and therefore power) each one sees individually. Parallel wiring keeps each element at full supply voltage, which is more common when you want each element operating at its full rated output independently — but total current draw adds up faster, which affects your upstream fusing and wire gauge decisions.

Protection still matters

Even though the element self-limits its own temperature (see how PTC ceramic heaters self-regulate temperature), the circuit around it still needs standard protection: appropriately rated fuses, correct wire gauge, and a switch or relay rated for the element’s steady-state current draw. None of this is optional just because the heating element itself is self-limiting — protection at the circuit level covers different failure modes than the element’s own thermal behavior does.

Lead configuration affects mounting, not wiring logic

For bare heating chip elements, lead placement (side-edge, single-surface, dual-surface) is a mechanical mounting consideration more than an electrical one — connect either lead to either side of your circuit. See how does a PTC heating element work for the physical construction.

If you’re specifying an element for a new circuit design, PTCWORKS can confirm resistance and current draw for your target voltage — reach our team.

For automotive-specific wiring, see how to wire a PTC car heater, and for real installed examples, our advanced automotive PTC heating case study shows how this wiring pattern gets applied across multiple vehicle subsystems.

Explore the PTCWORKS homepage for an overview of our full product range, or keep reading on the PTCWORKS blog for more guides like this one.