Knightsbridge 40W Constant Voltage LED Driver 12V - Non-Dimmable

The Knightsbridge 12DC40 is a 40W constant voltage LED driver that converts 230V 50Hz mains power to a stable 12V DC output for low-voltage LED lighting systems. The driver supplies up to 40W total load across one or more 12V LED strips, modules or fixtures, with captured terminal screws providing tool-free wire insertion and retention on both primary and secondary sides.

Designed for residential under-cabinet lighting, commercial display lighting and architectural accent lighting installations, the driver sits hidden behind panels, inside false ceilings or within furniture. The 166mm × 52mm × 24mm polycarbonate case is compact enough to fit standard kitchen plinths and cabinet voids. The Class II double-insulated construction means no earth connection is required, simplifying wiring in retrofit installations.

The driver carries IP20 ingress protection, limiting use to dry indoor locations away from direct water contact. Built-in protections cover open circuit (no load connected), short circuit (output terminals shorted), overheat (internal thermal cutoff) and overload (exceeding 40W), with the driver automatically recovering once the fault is cleared. The SELV (Safety Extra Low Voltage) rating confirms the 12V output poses minimal shock risk, making the driver suitable for installations near bathrooms and kitchens where low-voltage lighting is preferred.

Product Specification Sheet

Product Manual

What's the maximum LED strip length this driver can power?

The driver supplies up to 40W at 12V, which equates to approximately 3.3A maximum output current. The strip length depends on the power consumption per metre of your specific LED strip — a typical 4.8W/m strip would allow roughly 8 metres, while a denser 9.6W/m strip would allow around 4 metres. Check the strip datasheet and do not exceed 40W total load.

Can this driver be dimmed?

No. This is a non-dimmable constant voltage driver. Attempting to dim the 230V mains input with a standard trailing-edge or leading-edge dimmer will not work and may damage the driver. If dimming is required, use a dimmable driver model or install a 12V PWM dimmer on the low-voltage output side.

Where can the driver be installed?

The IP20 rating limits installation to dry indoor locations away from direct water contact. Typical placements include kitchen cabinet plinths, false ceilings, display cabinet voids and furniture cavities. Ensure adequate ventilation around the driver case to prevent heat build-up, and do not cover the driver with insulation material.

What protections does it carry?

The driver includes open circuit protection (safe to run with no load), short circuit protection (automatically shuts down if output terminals are shorted), thermal overload protection (cuts power if internal temperature exceeds safe limits) and overload protection (cuts power if total load exceeds 40W). The driver automatically recovers once the fault condition is cleared.