- Rubber Rib Mat Electrical 11KV (450V) is a high-quality, non-conductive rubber safety mat designed to provide insulation and protect workers from electric shocks. Certified to BS 921:1976, this mat is tested to withstand up to 11,000 volts, with a recommended working voltage of 450 volts. The regulatory standard is clearly printed on the reverse, ensuring compliance. The fine ribbed surface also offers excellent anti-slip protection, with an overall thickness of 6mm.