BS 7671: 2018 (the IET wiring regulations 18th edition) provides requirements and recommendations for the design, erection, initial verification, and periodic inspection and testing of electrical installations so as to provide for the safety and proper functioning for the intended use.
Two Levels of Protective Measures Must Exist Within Any Electrical Installation
Basic protection:Â
Protection against electric shock under fault-free conditions. Basic protection is provided to protect persons or livestock from coming into direct contact with electricity
Shock protection:
Protection against electric shock under single fault conditions. To protect against shock hazards is an integral component of electrical safety therefore current using equipment and circuits intended for use must have fault protection at all points of the system.
To achieve shock protection there are two necessities;
- The earthing of all exposed-conductive parts (metallic parts) of electrical equipment in the installation and extraneous-conductive parts (metallic pipes and framework) must be electrically bonded to an earth connection.
- Automatic disconnection of supply by a protective device e.g. fuse, circuit-breaker with an RCD
BS 7671:2018 has introduced a new additional protective device for detecting arcs faults which are caused by deteriorated or damaged cables or loose electrical connections, (which can be due to something as small as an untightened screw) or faulty current-using equipment that can lead to an irreversible incident. Such causes can lead to arc faults which can result in fire. Due to their characteristics, electric arcs cannot be detected by fuses, circuit-breakers or RCDs. Therefore, devices having a specific capability of detecting arcs faults are needed. These are called Arc Fault Detection Devices (AFDDs).
New type of loads
Electric vehicle charging equipment, solar photovoltaic (PV) inverters, electric heating, and many more loads are being added to existing electrical installations each having particular electrical characteristics. Therefore an important challenge within electrical installations is and will be, to apply appropriate and sufficient protection for these technologies to provide for safety.
Our fully qualified and experienced electricians have enough expertise to identify inadequacies, defects, or faults which would require improvement and recommend cost-effective solutions that ensure the continued operation of the installation in a safe and effective manner.
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