BS EN 50525 2 21 Cable

What is BS EN 50525-2-21?

BS EN 50525-2-21 is a British and European standard for low-voltage electrical cables within the wider EN 50525-2 series. It specifies requirements for flexible rubber cable with crosslinked elastomeric insulation and sheath, including recognised cable types such as H07RN-F, 318*TQ and 638*TQ.

These heavy-duty electrical cables are designed for applications requiring flexibility, mechanical durability and resistance to oils, weathering and demanding environmental conditions. Unlike PVC & LSZH cables, these rubber-insulated and sheathed cables use elastomeric compounds to provide greater flexibility across a wide operating temperature range.

Voltage Rating and Scope

BS EN 50525-2-21 covers flexible cables with rated voltages including:

300/500V for lighter-duty cable types
450/750V for heavy-duty types including H07RN-F

The standard covers single-core and multi-core flexible cables with copper conductors for fixed and movable electrical equipment. Applications include:

Industrial machinery
Portable equipment
Temporary power distribution
General installations requiring durable flexible wires and cables

Why Are Rubber Insulated Cables Used?

The crosslinked insulation and outer sheath provide the mechanical and environmental performance required for demanding electrical applications.

Key benefits include:

Excellent flexibility across a wide temperature range
Resistance to abrasion and mechanical stress
Broad chemical resistance to water and petroleum hydrocarbon-based fluids, including oils and gases
Good weathering and UV resistance
Suitable for indoor and outdoor power applications
Durable construction for movable electrical equipment

Cable Construction

Typical BS EN 50525-2-21 cable construction includes:

Conductor: Class 5 flexible stranded copper conductor
Core Insulation: Crosslinked elastomeric insulation (EPR)
Outer Sheath: Chlorinated Polyethylene (EF90), Polychloroprene (H07RN-F), Chlorosulfonated Polyethylene (H07BN4-F)
Sheath Colour: Black
Core Options: Single-core and multi-core constructions
Voltage Rating: Available in 300/500V and 450/750V cable types

Unlike standard PVC & LSZH cables, rubber constructions are selected where greater flexibility and environmental resistance are required. Specific construction, temperature ratings and compounds vary depending on the individual cable designation.

H07RN-F Rubber Cable

H07RN-F cable is one of the best-known heavy-duty cable types associated with BS EN 50525-2-21. It is a 450/750V flexible rubber cable with a Class 5 copper conductor, designed for applications where cables may be subjected to movement, mechanical stress or outdoor conditions.

Our flagship Extremeflex90 cable conforms to H07RN-F but offers the additional benefit of higher flexibility:

Less than 12 mm²: 3 × overall diameter
More than 12 mm²: 4 × overall diameter
Water resistance: AD8

H07RN-F is commonly used for industrial equipment, construction sites, generators, temporary power, stage and event lighting, portable machinery and power tools.