BS 7870 Instrumentation & Control Cables
BS 7870 RE-Y(St)YSWAY
Application
The armoured versions are generally used when the risk of mechanical damage is increased. The
galvanised steel wire armour provides excellent protection. Generally used within industrial process
manufacturing plants for communication, data and voice transmission signals and services, Also used
for the interconnection of electrical equipment and instruments, typically in chemical or petrolchemical
industry. The armored versions are generally use for outdoor installation for direct burial or installed in
the duct and suitable for wet and damp areas.
Construction
| Standards | BS 7870 |
|---|---|
| Conductor | Annealed plain copper consisting of a single strand of 0.8mm nominal diameter to BS6360 |
| Insulation | PVC (polyvinyl chloride) |
| Pairs | Two insulated conductors uniformly twisted together with a lay not exceeding 100mm |
| Binder tape | PETP transparent tape |
| Collective screen | Aluminium/polyester tape is applied over the laid up pairs metallic side down in contact with tinned copper drain wire, 0.5mm2 |
| Inner Sheath | PVC (polyvinyl chloride), type TI 1 to BS 7655 |
| Amour | Galvanized steel wire armour |
| Outer sheath | PVC Sheath, type TM 1 to BS 7655 |
Colour Code
Sheath colour: Black or blue
Electrical Properties
| Dielectric test | 2000V r.m.s. x 5’(core/core) |
|---|---|
| Insulation resistance | 1000MΩ x km (at 20°C) |
| Short circuit temperature | 250°C |
Mechanical
Temperature range during operation (fixed state): -40°C – +70°C
Minimum bending radius: 6 × Overall Diameter
Electrical Properties
| Conductor Area Size | mm2 | 0.5 | |
|---|---|---|---|
| Conductor Stranding | No. x mm | 1/0.8 | |
| Conductor resistance max | ohm/km | 36 | |
| Insulation resistance min | Mohm/km | 80 | |
| Max. Mutual Capacitance:< pair or adjacent cores | pF/m | 150 | |
| Capacitance between any core or screen max. | pF/m | 400 | |
| Test voltage | Core to core | V | 2000 |
| Core to screen | V> | 2000 | |
| Rated voltage max | V | 100 | |
Construction Parameters
| No.of pairs | No.and Dia. of Wires | Nominal Conductor Cross- Sectional Area | Nominal Thick-ness ofInsulation | NominalThick-ness of bedding | Nominal Dia.over Bedding | Nomina l Thick-ness of Armour | Nominal Thick-ness ofSheath | Nominal Dia. of Cable | Approx. Weight |
|---|---|---|---|---|---|---|---|---|---|
| no./mm | mm2 | mm | mm | mm | mm | mm | mm | kg/km | |
| 20 | 1/0.8 | 0.5 | 0.3 | 1.2 | 14.7 | 1.25 | 1.6 | 20.4 | 780 |