What is BS IEC 60287-2-3– Thermal resistance of cables in ventilated tunnels about?
BS IEC 60287 is an international standard on electric cables and the calculation of the current rating. In the series, BS IEC 60287-2 presents formulae or calculation methods for thermal resistances.
BS IEC 60287-2-3 describes a method for calculating the continuous current rating factor for cables of all voltages installed in ventilated tunnels. The method is applicable to any type of cable. The method applies to natural as well as forced ventilation. Longitudinal heat transfer within the cables and the surroundings of the tunnel is assumed to be negligible. All cables are assumed to be identical within the tunnel and it is assumed that the tunnel cross-section does not change with distance along the tunnel.
Who is BS IEC 60287-2-3 - Thermal resistance of cables in ventilated tunnels for?
BS IEC 60287-2-3 on cables installed in ventilated tunnels is relevant to:
- Cable manufacturers
- Cable installation designers
- Electrical engineers
- Technical engineers
- Local authorities
- Planning and designing authorities
- Regulatory authorities
Why should you use BS IEC 60287-2-3 - Thermal resistance of cables in ventilated tunnels?
BS IEC 60287-2-3 deals with the rating for cables installed in ventilated tunnels. In such situations, consideration of longitudinal temperature gradients is involved as the air flowing in the tunnel removes some heat from the cables. Heat transfer with the moving air is convective and is assumed to be either laminar or turbulent depending on the air velocity.
BS IEC 60287-2-3 provides a general simplified method to estimate the permissible current-carrying capacity of cables installed in ventilated tunnels, the ventilation being either natural or forced.
The method is based on the calculation of the temperature of the cable surface, the air in the tunnel, and the tunnel wall, as a function of the heat generated by the cables.
Thus, BS IEC 60287-2-3- compliant calculation methods can help cable installation designers and engineers to determine the durability and performance of their electric cables installed in ventilated tunnels.
