Mercury Hi-Flex 2 x 0.75mm² LSZH Speaker Cable - White 100m

The Mercury Hi-Flex is a 2 x 0.75mm² speaker cable with a white Low Smoke Zero Halogen (LSZH) sheath, supplied on a 100m reel. Each core uses 24 strands — 12 strands of oxygen-free copper (OFC) and 12 strands of copper-clad aluminium (CCA) — giving a balance of conductivity and flexibility across the 7mm overall cable diameter. The LSZH sheath minimises smoke and toxic fumes if the cable is exposed to fire, making it compliant with fire safety regulations in public buildings, schools, hospitals and commercial installations.

Designed for fixed audio distribution in background music systems, distributed PA installations, and multi-room audio setups, the cable handles speaker runs up to 6A continuous current. The double-insulated construction protects the conductors from mechanical damage during installation and provides additional safety over single-insulated designs. The 100m reel length suits multi-speaker installations where cable is run through ceiling voids, trunking or conduit to multiple zones.

The hi-flex construction keeps the cable manageable during installation despite the 7mm diameter, allowing tighter bend radii than standard twin-core speaker cable and reducing the effort needed to thread cable through narrow ceiling channels. The white LSZH sheath makes the cable visible against dark ceiling voids and suits surface-run installations in white-painted commercial spaces. The hybrid OFC/CCA strand construction reduces material cost without significantly compromising signal quality over typical background music speaker runs of 20-30m.

What does LSZH mean and why does it matter?

Low Smoke Zero Halogen sheathing produces minimal smoke and no toxic halogen gases if exposed to fire. This is required or strongly recommended in public buildings, schools, hospitals and commercial premises under UK fire safety regulations, where cable in ceiling voids could contribute to smoke levels during evacuation.

What's the difference between OFC and CCA conductors?

Oxygen-free copper (OFC) offers lower resistance and better conductivity than copper-clad aluminium (CCA). This cable uses a hybrid construction — 12 strands of each per core — to balance cost and performance. For typical PA and background music installations under 30m the hybrid construction performs adequately; for critical hi-fi or very long runs, pure OFC cable may be preferred.

What speaker impedance and power levels does this cable support?

The 0.75mm² cross-section and 6A current rating suit 8-ohm or 16-ohm speakers at modest power levels typical of distributed PA systems and background music. For high-power applications or very long runs, calculate voltage drop based on cable length, speaker impedance and amplifier power to confirm suitability.

How flexible is the cable during installation?

The hi-flex construction allows the cable to bend around corners and through ceiling channels more easily than standard twin-core speaker cable of the same diameter. The 7mm overall diameter is still thicker than typical domestic speaker cable, so tight 90-degree bends in narrow trunking may require gentle persuasion.