How To Wire A TWO WAY Smart Wifi Switch With No Neutral (UK)

Summary

• Goal: Install a UK one-gang two-way Wi‑Fi smart light switch using two-way wiring, but using the BCD “no neutral” model (i.e., the switches are designed to work without requiring a neutral connection).
• Key problem noted: The BCD instructions are “trash”/confusing and don’t match the presenter’s existing one-gang two-way circuit. The video is essentially a workable wiring guide for the presenter’s specific wiring layout.

What the smart switches require

The smart switches basically need:

• A permanent 12V live feed to the L terminal (live present whether the light is on or off).
• A switched live feed to the L1 terminal (the line that actually goes to the ceiling light to control it).

Two-way (master/slave) wiring logic

Identify the “master switch”

In the existing two-way setup:

• Only one of the two existing switches receives the permanent feed.
• The presenter identifies the master switch as the one with the permanent live (brown wire).

Wire the master switch

• Connect permanent live (brown) to terminal L.
• From the three-core cable between the switches, select the correct conductor that acts as the “link” to carry the needed switch live between the two smart devices.
• Connect the switched output going to the ceiling light into terminal L1 (so the smart switch can toggle the light).

Wire the second (non-master / “slave”) switch

Despite what the manual claims:

• The presenter states the second unit will not power up if you only put anything into L and leave L1 empty (or if it’s missing the required link conductors).
• You must route one of the three-core conductors so the second smart switch has the correct link to L1 (i.e., the ceiling-light / switch-live path).

Cable and wire handling notes

• In the three-core cable between the two switches:
  • The presenter refers to two “strapper” wires (used to link the two switches in a two-way circuit).
  • The “spare” strapper wire can be isolated (not connected).
• Brown wires leftover:
  • Any extra brown conductors are typically looped to the next feed/light.
  • The presenter connects brown appropriately to L on the master where required.

“No neutral” workaround (neutral loop still exists)

The presenter explains:

• There are neutrals present in the ceiling box (three blue conductors).
• Because the switches are BCD “no neutral” models, the smart devices don’t require neutral for operation.
• However, the neutral still needs to be carried onward, so:
  • The neutrals are joined/looped together using a 3-terminal WAGO.
  • The smart switch itself does not connect to neutral.

Capacitor requirement (flicker issue)

• The presenter had to install a capacitor bridging live and neutral at/near the ceiling to stabilize power for the switches.
• Without the capacitor:
  • The smart switches flicker on and off, even though the lamp is ~48W.
• With the capacitor installed:
  • Dimming and switching become stable (“working completely fine”).

App setup and smart features

After wiring, the switches are set up in the BCD app:

• Connect both devices to Wi‑Fi
• Configure them as one shared two-way / one-gang two-way control

The switches support:

• Control via the app
• Google Assistant voice control (e.g., “Hey Google, turn off living room light”)
• The presenter reports Google Assistant integration works seamlessly.

Physical installation notes

Depending on the backbox:

• You may need:
  • Plastic spacers
  • Possibly longer backbox screws
• The presenter notes:
  • They didn’t need a spacer on one switch,
  • but did on the more crowded master due to extra wiring and the neutral loop.

Cost note

• The presenter paid about £30 for the pair (≈ £15 each).

Main speakers / sources

• Main speaker: The video’s single presenter/DIY installer (no other named person).
• Product/source mentioned: BCD (manufacturer of the “no neutral” Wi‑Fi smart switches).