What Is an Intermediate Switch?

An intermediate switch is used when three or more switches control the same light or lighting circuit. It fits between two two-way switches, allowing the light to be controlled from three or more separate locations.

When do I need an intermediate switch?

If just two switches control a light — for example, at the top and bottom of a staircase — you only need two-way switches. Once a third switch position is added, such as a landing partway up the stairs, the middle switch (or switches) needs to be an intermediate switch.

How is an intermediate switch wired?

The two outer switches in the circuit are wired as standard two-way switches. The intermediate switch sits between them, with its terminals connected so that L1 and L2 on one side connect to one two-way switch, and the other pair of terminals connect to the other two-way switch. Terminal labelling can vary between manufacturers — sometimes you'll see two sets of L1 and L2, sometimes L1 through L4 — but the principle is the same: keep one pair going to each two-way switch.

Is an intermediate switch double pole?

No — an intermediate switch would not normally be a double pole switch. Double pole switches are used for isolating appliances (such as a washing machine or cooker), not for multi-way lighting circuits. See our double pole switch guide for more on that distinction.

Frequently Asked Questions

What is an intermediate switch?

An intermediate switch is used when three or more switches control the same light. It sits between two two-way switches to allow control from three or more locations.

Do I need an intermediate switch for a normal staircase?

Only if there's a third switch position, such as a landing. A standard staircase with just a top and bottom switch only needs two-way switches.

Is an intermediate switch the same as a double pole switch?

No. An intermediate switch is for multi-way lighting circuits. A double pole switch is used to isolate appliances and works differently.

Related guides: The Complete Wiring Guide and hallway sockets and switches.