Existalite XK.CB/50 – Limited Stock

A fluorescent central battery high-frequency inverter module is a specialized emergency lighting component. During power outages, it converts DC power from a central battery bank into high-frequency AC to illuminate standard fluorescent fixtures. It bypasses local mains control gear to provide reliable emergency escape route lighting.

Core Working Principle

Power Conversion: Draws from a low-voltage DC central battery system (typically 24V, 50V, or 110V).

High-Frequency AC: Utilizes solid-state switching (like MOSFETs) to generate a high-frequency (HF) alternating current. High-frequency operation is crucial for fluorescent tubes because it prevents flickering and cathode damage.

Hold-off Relays: Features built-in AC hold-off/change-over relays. When the building’s mains supply is healthy, the relay routes normal mains power through the standard ballast. When mains power fails, the relay drops out, immediately switching the lamp to the inverter’s emergency battery output.

For centralised systems, luminaires must be used that are suited to the voltage and curve form that the central unit generates in emergency mode. This is normally 220–230 V AC or the equivalent DC voltage and the majority of luminaires with HF ballasts can be connected to such installations. An inspection must be made however before the luminaires are energised.

In central systems, light sources with integrated starters may not be used, e.g. 2-pin compact fluorescent lamps. For central systems, we only recommend luminaires equipped with either HF ballasts, LEDs, incandescent lamps or halogen light sources.

Typical Specifications & Features

Lamp Compatibility: Generally rated for fluorescent lamps ranging from 4W to 100W (including T5, T8, and compact fluorescent lamps).

Sinusoidal Output: High-efficiency sine-wave output ensures low harmonic distortion and prolonged lamp life.

Compliance: Modules are typically designed to comply with life-safety standards like EN 61347, EN 50172, and EN 50171, ensuring they meet rigorous emergency lighting requirements.

Common Applications

These inverters are primarily used in commercial properties, hospitals, and large industrial facilities to convert standard fluorescent luminaires into maintained or non-maintained emergency lights. They allow facility managers to use existing decorative light fixtures without needing to install dedicated, self-contained emergency bulkheads.

If you are looking to source replacement modules or evaluate repair options for your site, it helps to know:

The system’s battery voltage (e.g., 24V, 50V, or 110V)The wattage and type of fluorescent tubes you are running

Key Specifications & Features

Maintained vs. Non-Maintained: Can be wired for maintained operation (light stays on continuously, switching to battery during an outage) or non-maintained (light is off normally, turning on only when the power fails).

DC Voltage Compatibility: Must be rated to handle high-voltage DC supplies (commonly between 186 V and 275 V) which are typical for central battery systems.

Energy Management: Electronic ballasts automatically reduce light output in battery mode, which allows for safer, smaller, and more cost-effective central battery capacities.

Important Considerations for 2026

The Fluorescent Phase-Out: The UK and EU have implemented bans on the sale of general-purpose fluorescent tubes. If you are upgrading, many commercial spaces are now bypassing these ballasts and retrofitting their fixtures with compatible LED tubes and LED emergency drivers.

Troubleshooting: Failing ballasts typically exhibit buzzing sounds, flickering, or failure to ignite. Always ensure the replacement ballast precisely matches the lamp’s wattage and type.

https://www.fagerhult.com/Support-center/Emergency-lighting/Operation-and-light-source/

Existalite (part of the Thomas & Betts Group, a member of the ABB family) is a prominent UK-based manufacturer and supplier specializing in emergency lighting solutions and control gear. Their products are widely utilized in the commercial marine, rail, petrochemical, and land-based industries.

Core products include:

Emergency Inverters & Ballasts: Critical backup modules (e.g., ZT.3G/C and XCR series) designed to run fluorescent or LED lamps during power outages.

Low-Level Way Guidance: Market leaders in low-mounted, modular LED emergency systems (such as the Guide-LITE range) designed to safely illuminate escape routes when smoke impairs overhead lighting.

Combo Units & Gear Trays: Integrated, maintained emergency combination units often supplied in pre-wired gear trays.

Because many of their older fluorescent-era inverters and modules have been discontinued, replacements, alternatives, or compatible parts are frequently sourced through specialized trade suppliers.