01
Copper Or Aluminum BS7870 XLPE Split Concentric Cable
Compliances
This Standard applies to fixed installations in both PVC and LSZH sheathing, with both copper and aluminium conductors. The type of cable you need depends on the type of connection and the arrangement of the neutral and protective conductors. For more information, see BS7671 section 312.2.
Application
BS7870 Part 3 covers low-voltage cables used for electricity supply. They are buried underground to connect houses or businesses to the grid. These cables can't be used overhead.
The standard also applies to medium-voltage cables under BS7870 Part 4 for single-core cables up to 33kV and 3-core cables up to 11kV.
Parameters
Type I Aluminum Concentric
| NO. OF CORES | NOMINAL CROSS SECTIONAL AREA | NOMINAL OVERALL DIAMETER | NOMINAL WEIGHT | MAXIMUM DC RESISTANCE OF CONDUCTOR AT 20°C | MAXIMUM DC RESISTANCE OF CONCENTRIC CONDUCTOR AT 20°C | CURRENT CARRYING CAPACITY Amps | ||
| mm2 | mm | kg/km | ohms/km | ohms/km | In Air | Clipped Direct | Enclosed in Conduit on a Wall | |
| 1 | 25 | 13 | 300 | 1.2 | 1.3 | 127 | 119 | 105 |
| 1 | 35 | 14 | 390 | 0.868 | 0.91 | 158 | 147 | 128 |
| 3 | 25 | 23 | 650 | 1.2 | 1.3 | 97 | 90 | 84 |
| 3 | 35 | 25 | 820 | 0.868 | 0.91 | 120 | 112 | 103 |
Type II Aluminum Split Concentric PARAMETER
| NO. OF CORES | NOMINAL CROSS SECTIONAL AREA | NOMINAL OVERALL DIAMETER | NOMINAL WEIGHT | MAXIMUM DC RESISTANCE OF AT 20°C ohms/km | CURRENT CARRYING CAPACITY Amps | ||||
| mm2 | mm | kg/km | CONDUCTOR | Neutral | Earth | In Air | Clipped Direct | Enclosed in Conduit on a Wall | |
| 1 | 25 | 15 | 490 | 1.2 | 1.2 | 1.2 | 127 | 119 | 105 |
| 1 | 35 | 16 | 610 | 0.868 | 0.76 | 1.2 | 158 | 147 | 128 |
| 3 | 25 | 23.5 | 830 | 1.2 | 1.2 | 1.2 | 97 | 90 | 84 |
| 3 | 35 | 26 | 1030 | 0.868 | 0.76 | 1.2 | 120 | 112 | 103 |
Type III Copper Concentric PARAMETER
| NO. OF CORES | NOMINAL CROSS SECTIONAL AREA | NOMINAL OVERALL DIAMETER | NOMINAL WEIGHT | MAXIMUM DC RESISTANCE OF CONDUCTOR AT 20°C | MAXIMUM DC RESISTANCE OF CONCENTRIC CONDUCTOR AT 20°C | CURRENT CARRYING CAPACITY Amps | ||
| mm2 | mm | kg/km | ohms/km | ohms/km | In Air | Clipped Direct | Enclosed in Conduit on a Wall | |
| 1 | 4 | 8.5 | 140 | 4.61 | 4.8 | 42 | 41 | 37 |
| 1 | 16 | 12 | 370 | 1.15 | 1.2 | 100 | 99 | 88 |
| 1 | 25 | 14 | 550 | 0.727 | 0.76 | 135 | 130 | 117 |
Type IV Copper Split Concentric PARAMETER
| NO. OF CORES | NOMINAL CROSS SECTIONAL AREA | NOMINAL OVERALL DIAMETER | NOMINAL WEIGHT | MAXIMUM DC RESISTANCE OF CONDUCTOR AT 20°C ohms/km | CURRENT CARRYING CAPACITY Amps | |||
| mm2 | mm | kg/km | Metal-Coated Wires | Plain Wires | In Air | Clipped Direct | Enclosed in Conduit on a Wall | |
| 1 | 4 | 10 | 190 | 4.8 | 4.8 | 42 | 41 | 37 |
| 1 | 16 | 14 | 530 | 1.2 | 1.2 | 100 | 99 | 88 |
| 1 | 25 | 16 | 710 | 1.2 | 0.76 | 135 | 130 | 117 |
| 3 | 35 | 28.5 | 1900 | 0.76 | 0.55 | 129 | 120 | 110 |
What is Split Concentric Cable
Split concentric cable is a type of power cable consisting of a center conductor surrounded by two layers of insulation and concentric neutral and phase conductors. Concentric neutral conductors are usually made from a combination of wire and tape to provide concentric layers around the phase conductors.
Split concentric cables are commonly used in medium voltage power distribution systems, especially in urban areas, where the concentric neutral design helps reduce the effects of electromagnetic interference and provides a more balanced potential distribution. This design also helps to increase the cable’s resistance to electrical faults and provides a degree of mechanical protection.
Split concentric cable designs are typically used in applications requiring a high degree of reliability and performance, such as underground distribution networks and other medium voltage transmission systems. The concentric neutral point configuration helps improve the electrical characteristics of the cable and provides a level of fault tolerance, making it suitable for critical power applications.