If you have installed a Retrotouch Crystal Touch Switch or Dimmer and your LED light bulbs are flickering, pulsing, or faintly glowing even when the switch is turned completely off, this is a common issue known as phantom leakage or low-load instability.
This guide explains why this happens and how to completely eliminate it using the included Retrotouch capacitor.
Retrotouch touch switches are advanced electronic devices. Unlike traditional mechanical switches that physically snap an electrical contact open and closed, a touch switch uses internal solid-state circuitry to control the power.
The Constant Micro-Current: To keep the backlit glass touch rectangles illuminated at night, a tiny, harmless micro-current (approximately 0.02W) continuously flows through the circuit.
The Low-Wattage LED Problem: Old incandescent bulbs absorb this tiny idle current without reacting. However, modern highly efficient LED bulbs require very little energy to illuminate. The continuous micro-current from the switch can gradually charge the internal capacitor inside an LED bulb. Once charged, the bulb releases the energy, causing a faint glow, periodic flash, or constant flicker even though the switch is in the "OFF" position.
To resolve this issue, Retrotouch provides a specialized ceramic safety capacitor. This component acts as an electrical "bypass filter," soaking up the background micro-current when the switch is off and preventing it from reaching your light bulbs.
Warning: Electrical work must be performed in accordance with IEE regulations (BS 7671). Always isolate the circuit power at your property's main consumer unit before starting.
Locate the First Lamp: Identify the first light fixture on the switched circuit (the light bulb physically closest to the touch switch). You do not need a capacitor for every single bulb; you only need one capacitor per switched circuit line.
Access the Wiring Connections: Remove the light bulb housing or drop down the ceiling rose/pendant block of that first lamp to access its electrical terminal blocks.
Wire in Parallel (Across the Load): Connect the two leads of the capacitor directly across the Live (Switched Live) and Neutral terminals feeding that first light fixture.
Note: The capacitor is non-polarized, meaning it does not matter which lead goes into Live or Neutral.
Do not install it in series: The capacitor must bridge across the Live and Neutral terminals together on the same fixture.
Secure and Close: Ensure all terminal screws are tightly clamped down, that no bare copper wires are exposed, and tuck the capacitor neatly inside the ceiling rose or light fitting.
Test the Circuit: Re-attach your light fixtures, restore the mains power at the breaker panel, and wait 2 minutes for the touch switch to initialize. Turn the switch off—your bulbs will now remain completely dark and flicker-free.
If you have installed the capacitor but the flickering persists, verify your circuit parameters against the following engineering rules:
Non-Dimmable Bulbs on Dimmer Circuits: If you are using a Retrotouch Touch Dimmer switch, your LED bulbs must be explicitly labelled as dimmable. Non-dimming LEDs will flicker violently or buzz if connected to a dimming touch module.
Minimum Circuit Load Thresholds: Standard 1-Way touch switches require a minimum circuit load of 3W to maintain stability. If your single LED bulb is a specialized ultra-low-power variant (e.g., a 1.5W or 2W decorative bulb), it will fall below the switch's initialization threshold, leading to unstable performance. Adding a second bulb to the circuit or shifting to a slightly higher wattage bulb will instantly fix the issue.
Fluorescent and Energy-Saving Loads: Retrotouch dimmer switches are strictly incompatible with old fluorescent tubes, compact fluorescent lamps (CFLs), or non-LED energy savers. These loads draw power differently and can cause catastrophic failure to the internal touch dimming transistors.