Hoe sluit je een Shelly correct aan achter een lichtschakelaar?

How do you correctly connect a Shelly behind a light switch?

Smart lighting without smart bulbs

When people start with home automation, they often think they have to replace all their light bulbs with smart ones. In practice, that is usually not necessary.

With a Shelly module behind an existing switch, you can make a standard lighting circuit smart while continuing to use your existing switches.

This is not only cheaper but also more reliable and user-friendly.

Why choose a Shelly behind the switch?

A Shelly module is installed behind the existing switch or in a junction box.

This allows you to:

✅ Control lighting via an app
✅ Control lighting via Home Assistant
✅ Create automations
✅ Use voice control
✅ Keep existing switches

For visitors, nothing changes. The lighting still works via the physical switch.

Which Shelly should you use?

Shelly 1 Gen4

Ideal for:

  • Lighting
  • Outdoor lighting
  • Pulse relays
  • Garage doors

Shelly 1PM Gen4

Ideal when you also want to measure energy consumption.

Perfect for:

  • Lighting
  • Wall outlets
  • Electrical appliances

Shelly Dimmer Gen4

Suitable when you want to dim existing lighting without installing smart bulbs.

Is a neutral wire necessary?

That depends on the installation.

Most Shelly modules work best when both phase and neutral are present.

In many modern homes, this is not an issue.

In older installations, it may be necessary to use a different connection method or pull an extra wire.

Always check the electrical installation before you begin.

Integration with Home Assistant

A major advantage of Shelly is the excellent Home Assistant integration.

After adding the module, you can:

  • Automate lighting
  • Use presence detection
  • Set timers
  • Monitor energy consumption
  • Create scenes

Examples:

Smart hallway lighting

Motion detected?

➡ Light on

No motion for 5 minutes?

➡ Light off

Outdoor lighting

Sunset?

➡ Lighting on

11:30 PM?

➡ Lighting off

Presence simulation

During vacations, lights can be switched on automatically at different times so the house appears occupied.

Smart bulbs or relays?

Many people are torn between smart bulbs and a relay module.

Smart bulbs

Advantages:

  • Colors
  • Easy installation

Disadvantages:

  • More expensive
  • Work less effectively when someone switches off the wall switch

Relays

Advantages:

  • Keep existing light bulbs
  • Often cheaper
  • Physical switch remains functional
  • Full Home Assistant integration

For most fixed lighting in the home, a Shelly module is the best choice.

Safety first

Working on an electrical installation carries risks.

✅ Always turn off the power.
✅ Verify that the power is off.
✅ Consult an electrician if you are in doubt.

Conclusion

With a Shelly module behind an existing switch, you can make a standard lighting circuit smart quickly and affordably. You retain familiar operation while enjoying all the benefits of Home Assistant and modern home automation.

For most situations, the Shelly 1 Gen4, Shelly 1PM Gen4, and Shelly Dimmer Gen4 are the best choices to get started.

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