Certified Enterprise Risk Analyst (CERA)

Correct: In accordance with SANS 10142-1 and the international standards it aligns with (such as IEC 60364-7-722), EV charging stations present a unique risk where DC leakage from the vehicle’s battery system can saturate the magnetic core of a standard Type A or AC RCD, rendering it unable to trip during an AC fault. To mitigate this, the code requires either a Type B RCD (which detects both AC and DC leakage) or a Type A RCD paired with a dedicated 6 mA RDC-DD (Residual Direct Current Detecting Device).

Incorrect: Type AC RCDs are generally unsuitable for EV charging because they cannot detect DC leakage and are prone to ‘blinding’. DC leakage protection is a requirement for AC charging (Mode 3), not just DC charging (Mode 4). Type S RCDs are time-delayed devices used for discrimination and do not provide the instantaneous protection required for EV charging points, nor do they address the specific 6 mA DC leakage threshold required by the safety standards.

Takeaway: For EV charging installations, specialized RCD protection (Type B or Type A with RDC-DD) is mandatory to ensure the safety system remains functional in the presence of DC residual currents.

Correct: According to SANS 10142-1, specifically regarding the separation of services, cables of different voltage levels (such as 230 V power and low-voltage data) must not occupy the same conduit or trunking compartment unless they are separated by a partition or the data cables are insulated for the highest voltage present. The first step in addressing this deficiency is ensuring physical segregation through a non-conductive longitudinal partition to maintain safety and prevent the transfer of hazardous voltages to the data system.

Incorrect: Replacing UTP with STP cabling may reduce electromagnetic interference but does not satisfy the safety requirements for physical segregation between different voltage systems as mandated by the wiring code. Installing surge protection is a secondary measure for transient protection and does not address the fundamental installation deficiency of shared containment. Identification through color-coding or tape is a requirement for clarity but does not provide the physical or dielectric barrier necessary to prevent electrical hazards between power and data circuits.

Takeaway: SANS 10142-1 requires strict physical segregation or specific insulation levels when data and power cables share containment to prevent electrical hazards and ensure system integrity.

Correct: According to SANS 10142-1, Clause 6.16.4, a transformer that is not an integral part of an appliance must be provided with a means of isolation on the supply side that disconnects all phase conductors. Furthermore, Clause 6.16.4.2 specifically requires that such transformers be protected against overcurrent to prevent fire hazards and equipment damage.

Incorrect: Option b is incorrect because while secondary isolation may be a design choice for specific loads, the regulatory requirement focuses on the supply-side isolation. Option c is incorrect because the earthing of the secondary winding depends on the specific circuit type (such as SELV, PELV, or IT systems) and is not a universal requirement for all transformer types. Option d is incorrect because overcurrent protection, not necessarily RCD protection, is the specific requirement for transformer installations under this section of the code.

Takeaway: SANS 10142-1 mandates that standalone transformers have dedicated supply-side isolation for all phase conductors and appropriate overcurrent protection.

Correct: SANS 10142-1 (The Wiring Code) does not provide exemptions for temporary, cultural, or ceremonial installations regarding fundamental safety. All circuits supplying socket-outlets or temporary equipment in such environments must be protected by a 30mA earth leakage protection device to prevent electric shock, particularly in areas where environmental conditions (like water usage) increase the risk of conductivity.

Incorrect: The suggestion of a temporary waiver (option b) is incorrect as the code does not allow for the bypassing of life-safety devices based on event duration. The proximity rule (option c) is a misunderstanding of specific zone requirements for bathrooms or pools, whereas temporary installations have broader protection requirements. While isolation transformers (option d) provide a high level of safety, they do not serve as a universal regulatory substitute for the mandatory 30mA earth leakage protection required for general temporary circuits under the standard.

Takeaway: All temporary electrical installations, regardless of cultural or ceremonial significance, must strictly adhere to the fundamental safety requirements of SANS 10142-1, including 30mA earth leakage protection.

Correct: According to SANS 10142-1 (Clause 6.1.10), cables of different systems (such as telecommunication and power) installed in the same enclosure must be separated by a partition or every cable must be insulated for the highest voltage present. Furthermore, if a telecommunication cable contains metallic parts (like armor or strength members), these parts must be bonded to the earthing system to prevent them from becoming live and posing a safety risk in the event of a fault in the power circuits.

Incorrect: Option b is incorrect because while insulation is a factor, it does not address the mandatory bonding of metallic members required by the code. Option c is incorrect because SANS 10142-1 generally requires a common bonding system for safety to ensure all conductive parts are at the same potential; independent electrodes can create dangerous potential differences. Option d is incorrect because the primary concern of SANS 10142-1 is safety and segregation rather than electromagnetic compatibility (EMC) performance, and screening power cables does not remove the requirement for segregation or bonding of the fibre’s metallic parts.

Takeaway: When fibre optic cables with metallic components share enclosures with power circuits, SANS 10142-1 mandates physical segregation or specific insulation ratings, along with mandatory bonding of all metallic elements to the earthing system.

Correct: According to SANS 10142-1, specifically the clauses relating to fixed appliances (6.16), every air-conditioning unit must have a disconnecting device. This device must be positioned within 1.5 meters of the appliance and must be within sight of the person working on the unit. If the isolator cannot be placed within sight, it must be a type that can be locked in the open position to prevent accidental re-energization while a technician is performing maintenance.

Incorrect: Providing a single common isolator at the roof access point fails to meet the requirement for local isolation within 1.5 meters of each specific appliance. Relying solely on circuit breakers located several floors away is non-compliant because they are not within sight of the unit, and standard DB breakers are not always accepted as the primary local disconnecting device unless they meet specific proximity and locking criteria. Suggesting that only indoor units require isolation is a safety violation, as the outdoor condenser units contain high-voltage components and moving parts that require local isolation for safe servicing.

Takeaway: SANS 10142-1 requires HVAC units to have a local, visible, and accessible disconnecting device within 1.5 meters, or a lockable isolator if visibility cannot be maintained.

Correct: In Group 2 medical locations, such as those used for intracardiac procedures, SANS 10142-1 specifies that a medical IT (isolated) system must be used for circuits supplying medical electrical equipment intended for life support or surgical applications. This system includes an insulation monitoring device (IMD) that alerts personnel to a first insulation fault, allowing the procedure to continue without an immediate power interruption, which is vital for patient safety.

Incorrect: Standard Residual Current Devices (RCDs) are inappropriate for life-support circuits in Group 2 locations because they would disconnect power on the first fault, potentially endangering the patient. While TN-S systems are common in general installations, they do not provide the fault tolerance required for Group 2 medical locations. TN-C-S systems are generally prohibited within medical locations beyond the main distribution board because they can introduce stray currents into the earthing system, posing a risk of micro-shock to patients.

Takeaway: Group 2 medical locations require a medical IT system with insulation monitoring to ensure that a single phase-to-earth fault does not result in a loss of power to life-critical equipment.

Correct: In accordance with SANS 10142-1 and the specific requirements for EVSE (Electric Vehicle Supply Equipment), measures must be taken to protect against DC residual currents which can ‘blind’ standard RCDs. The code requires that every AC charging point be protected by its own RCD, which must be either a Type B RCD or a Type A RCD combined with equipment (RDC-DD) that ensures disconnection if a DC fault current exceeding 6 mA is detected.

Incorrect: Using a single Type AC RCD for multiple points is prohibited because Type AC devices are not sensitive to DC components and can fail to trip entirely in the presence of DC leakage. Standard Type A RCDs alone are insufficient because they are only rated to handle up to 6 mA of smooth DC before their magnetic core saturates, rendering them ineffective for AC fault protection. The requirement for DC leakage protection applies specifically to AC charging points (Level 1 and 2) because the vehicle’s rectification process can leak DC back into the AC supply side.

Takeaway: To ensure electrical safety in EV installations, each charging point must have dedicated protection capable of detecting and interrupting DC residual currents exceeding 6 mA.

Correct: In accordance with SANS 10142-1, specifically Clause 7.14 regarding locations where a risk of fire exists due to the nature of processed materials, electrical equipment must be selected and installed so that its temperature in normal operation cannot cause a fire. This requires an Ingress Protection (IP) rating of at least IP5X to prevent dust accumulation inside the equipment and ensuring surface temperatures remain below the ignition threshold of the specific dust layer.

Incorrect: Clearance distances alone are insufficient without proper ingress protection in high-dust environments. While RCDs provide earth fault protection, they do not mitigate the fire risk of dust settling on hot surfaces. Using Type S devices is a coordination strategy for discrimination and does not address dust ingress. Classifying a woodworking area as Zone 0 is incorrect as Zone 0 applies to continuous explosive gas atmospheres, whereas dust environments require different protection methods (such as Ex t) and are classified as Zone 21 or 22.

Takeaway: Electrical equipment in woodworking areas must be dust-protected (IP5X) and temperature-limited to prevent the ignition of combustible sawdust.