The Legal Requirement

British Standard Specification BS921:1976 deals with insulating mats made of solid natural or synthetic rubber used as floor coverings near electrical apparatus where circumstances involve the possibility of direct contact with conductors whose voltage does not exceed 650 VRMS (Root Mean Square) to earth.

The Standard contains no provisions relating to the use of rubber mats as secondary insulation for conductors at voltages greater than 650 VRMS to earth. All mats must be solid and not perforated. The upper surface may have a ribbed, fluted or other suitable pattern, or may be plain. The lower surface may be finished in cloth imprint. Plain mats shall not be less than 6.5mm in thickness. Patterned mats shall not be less than 6.5mm thickness at the root of the pattern.

Mats shall have a minimum width of 900mm to accord with the regulations concerning the minimum width of a working pattern or passageway associated with a switchboard on which there are exposed line conductors. Where the regulations do not apply, the same minimum width is recommended.

All material to this Specification is tested to 15,000 VRMS with a 650 volt working.

Products and Prices

Morgan Fire Protection can supply and fit a product that complies fully with all the requirements of this Specification. It is manufactured from a natural rubber black compound with a fine fluted upper surface and is finished with a cloth imprint on the black surface.

The fine fluted upper surface of our product gives the additional safety feature of an ‘anti-slip’ surface, which under some working conditions can be very important.

Black fine fluted Electrical Safety/Switchboard Rubber Matting to BS921 tested to 11Kv for maximum 450v working

Thickness Width Approx Weight Part No.
6mm 915mm 7.5 kg per metre ELEC6.36
6mm 1220mm 10 kg per metre ELEC6.48


Black fine fluted Electrical Safety/Switchboard Rubber tested to BS921 tested to 15Kv for maximum 650v working 

Thickness Width Approx Weight Part No.
9.5mm 915mm 12.6 kg per metre ELEC9.36
9.5mm 1220mm 16.8 kg per metre ELEC9.48