4 Tips for Choosing the Cable for Your Electric Water Heater
4 Tips for Choosing the Cable for
Your Electric Water Heater
Introduction
In this article, we will focus on non-armoured polyvinyl chloride (PVC) insulated cables designed for fixed installations and operation at voltages up to and including 450 V to earth. These cables are commonly used in electrical installations, including connections to electric storage heaters. However, it is crucial to ensure that the cables used comply with current standards to avoid safety hazards and insurance issues.
Why BS 2004?
During the British colonial period in Singapore, electrical cables conforming to BS 2004:1955 were widely used. These cables were specified in imperial units, such as 40/00076 (similar to 1mm²) or 70/00076 (similar to 1.5mm²). For 3-core cables, the label would read 3C 70/00076, with 00076 representing the core diameter in square inches.
Cables approved at that time would bear labels like 3C 70/00076 BS2004. However, the older British Standard BS2004 was superseded by BS6004:1995, which introduced specifications in metric units (mm) instead of imperial units. Consequently, BS2004-specified cables are no longer approved for use after 1995.
Why is BS 2004 Cable Still in Use in Singapore?
Despite being outdated, BS 2004-specified cables remain popular in Malaysia and can still be found in hardware shops. Many of these cables lack proper labelling, making it difficult to identify their compliance status. Handymen and technicians, often commuting from Johor Bahru (JB) for cost reasons, may purchase these cables without realising they do not meet Singapore’s current standards.
Most of these workers lack formal training and certification in electrical installations, making them unaware of the differences between BS2004 and BS6004. To them, these are merely numbers without significant meaning.
Problems with Using Outdated Cables
- Insurance Issues: Insurance policies may deny claims if non-compliant electrical components are used or if regulated works are carried out by unlicensed individuals. This can be considered negligence.
- Incorrect Sizing: Without proper specifications printed on the cable jacket, it is challenging to determine the correct size, leading to potential safety risks.
- Fire Hazards: Untested cables may overheat, increasing the risk of fire.
- Connection Failures: Poor-quality cables can burn out at connections, damaging appliances.
- Troubleshooting Costs: Burnouts and breaks may require professional troubleshooting, resulting in unnecessary expenses.
What Should Consumers Do?
- Check Cable Compliance: Ensure that the cable used by the installer has BS 6004 printed on it.
- Cable Size: Typically, a cross-sectional diameter of 2.5mm² or higher is required.
- Proper Connections: Connections should be made in approved junction boxes or isolators rated at 20A or higher.
- MCB Rating: The Miniature Circuit Breaker (MCB) should be 20A or lower, not higher.
- Heater Switch: Use a 20A heater switch instead of a 13A socket outlet.
- Earth Cable Connectivity: Ensure the earth cable is properly connected to the main earthing system.
- RCCB Testing: Test the Residual Current Circuit Breaker (RCCB) to ensure the heater circuit is connected and will cut the supply in case of equipment fault.
Conclusion
In Singapore, all electrical works must comply with SS 638:2018. Cable selection should adhere to BS 6004:2012+A1:2020, titled “Electric cables. PVC insulated and PVC sheathed cables for voltages up to and including 300/500 V, for electric power and lighting.” By following these guidelines, consumers can ensure the safety and compliance of their electrical installations, avoiding potential hazards and insurance issues.
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