An instrument and control installation’s scope of work often never makes a request for a certificate of compliance: it is assumed to be an electrical function and hence many installations are non-compliant. To put this in perspective, take note of the following to assist compliance:
The Occupational Health and Safety Act (Act 85) of 1993 and Regulations (OSH Act) are South African laws. Like any other laws, if they are not upheld it is an offence and legal action could be taken, resulting in fines and/or imprisonment.
The OHS Act, which is administered by the Chief Inspector of Occupational Health and Safety of the Department of Labour, requires that electrical installations comply with the requirements of SANS 10142.
The OSH Act works in conjunction with SANS (South African National Standards) which is the “How we do it,” – the OSH Act tells us what to do and SANS gives us the method/minimum requirements of how it should be done to comply with the law.
For electrical installations, SANS 10142 and all other related SANS standards are applicable. The latest version is SANS 10142-1:2017 Edition 2. (All information in this article is taken from the latest version of SANS 10142-1:2017 Edition 2.) There are 2 parts to SANS 10142:
• Part 1: Low-voltage installations, SANS 10142-1:2017 Edition 2 (applicable to instrumentation).
• Part 2: Medium-voltage installations above 1000 V AC and not exceeding 22 000 V AC and up to and including 3 MVA installed capacity.
The provisions of this part of SANS 10142 apply only to the selection and application of electrical equipment, appliances and accessories, which are part of the fixed electrical installation. They do not apply to the construction and safety of the equipment, appliances and accessories; those aspects are dealt with in other SANS standards.
Electrical installation (3.33)
Machinery, in or on, any premises that is used for the transmission of electrical energy from a point of control (point at which a consumer can, on or in any premises, switch off the electrical installation from the electricity supplied from the point of supply) to a point of consumption (point of outlet, or the supply terminal of machinery) anywhere on the premises, including any article that forms part of such an installation, irrespective of whether or not it is part of the electrical circuit.
Responsibility for electrical installations
The user or lessor of an electrical installation, as the case may be, shall be responsible for the safety, safe use and maintenance of the electrical installation he or she uses or leases.
Certificate of compliance – OSH Act (EIR 7)
Sub-regulation (1) – subject to the provisions of subregulation (3) (OSH Act) every user or lessor of an electrical installation, as the case may be, shall have a valid certificate of compliance for that installation, which shall be accompanied by a test report in the format approved by the chief inspector, in respect of every such electrical installation – OSH Act - Electrical Installation Regulation (EIR) 7.1.
Sub-regulation (3) – sub-regulation (1) shall not apply to an electrical installation that existed prior to 23 October 1992, and where there was no change of ownership after 1 March 1994: Provided that, if any addition or alteration is effected to such an electrical installation, the user or lessor of the electrical installation, as the case may be, shall obtain a certificate of compliance for the whole electrical installation, where after the provisions of sub-regulation (1) shall be applicable to such electrical installation. OSH Act - Electrical Installation Regulation (EIR) 7.3.
Most users or lessors are found to be very confused regarding the above COC requirements; many just read the first few lines of sub-regulation (3) and assume a COC is not required, however, if read in context, a COC is mandatory.
Sub-regulation (4) – where any addition or alteration has been effected to an electrical installation for which a certificate of compliance was previously issued, the user or lessor of such electrical installation shall obtain a certificate of compliance for at least the addition or alteration.
Should there be no COC available with the necessary test and inspection report, then a COC of the entire installation shall be mandatory.
Issuing of certificate of compliance – OSH Act (EIR 9)
No person other than a registered person may issue a certificate of compliance (COC).
OSH Act - 2.4.4 Sub-regulation 4: a registered person shall exercise general control over all electrical installation work being carried out, and no person may allow such work without such control.
General control in relation to electrical installation that is being carried out includes instruction, guidance and supervision in respect of that work. This sub-regulation emphasises the point that no-one may do installation work unless he or she does the work under the general control of a registered person, or they themselves are a registered person.
The intention of the regulation is to ensure that installation work is carried out under clear instructions, guidance and proper supervision and that it complies with the health and safety standard.
SANS 10142 requires that a registered person will issue a COC together with a test report. The certificate shall be in the form of the Certificate of Compliance published in the Electrical Installation Regulations, 2012, and the test report shall be in the form of the test report in this part of SANS 10142-1.
The equipment shall be suitable for operation on the maximum steady (rms) voltage, and overvoltage to which it is likely to be subjected is limited a tolerance of ±10% on these voltages. Standard voltages of single phase is 230 V AC, and 230/400 V AC three-phase four-wire.
Low voltage (LV) (3.84.3): voltage that does not exceed 1000 V AC or 1500 V DC, including Extra Low Voltage (ELV) that does not exceed 50 V AC or 120 V DC.
Voltage drop (126.96.36.199): when all conductors of an AC installation are carrying their maximum estimated load, the difference in voltage (the voltage drop) between the point of supply and any point of outlet or terminals of fixed appliances shall not exceed 5% of the standard voltage or of the declared phase-to-neutral voltage. Maximum permissible voltage drop between phases and neutral is 5% of 230 V, i.e., 11,5 V. Voltages on control circuits should preferably not exceed 230 V AC or 110 V DC.
Instrumentation and control equipment that is supplied with the above voltages, but not limited to, shall have a COC, e.g. all 230 V AC supplied equipment such as magnetic flowmeter transmitters, level transmitters, power supply to transformers in control cabinets, solenoid valve coils (110 V AC or 230 V AC), electric actuators, digital indicators, relays, analysers/analyser systems, consistency transmitters and DCS/PLC panels, networking equipment , distribution boards for instrumentation in rack rooms and plug points in panels.
All electrical contractors shall have valid registration from the Department of Labour (chief inspector) stating that they are electrical contractors; included on that letter is the name/s of the registered persons that are employed on a permanent basis.
OSH ACT - 2.4.4 Sub-regulation 4: a registered person shall exercise general control over all electrical installation work being carried out, and no person may allow such work without such control. General control in relation to electrical installation includes instruction, guidance and supervision in respect of that work.
Installation work (OSH Act - 2.3.2 sub-regulation 2) means:
• The installation, extension, modification or repair of an electrical installation.
• The connection of machinery at the supply terminals of such machinery.
• The inspection, testing and verification of electrical installations for the purpose of issuing a certificate of compliance.
Earthing is of utmost importance in an installation
Earthed: so connected to the general mass of earth as to ensure, at all times, an immediate discharge of electrical energy without danger.
Earth electrode: one or more conductive parts that are embedded in the earth for the purpose of making effective electrical contact with the general mass of the earth.
Earthing conductor: includes any clamp or terminal, by which the connection of the consumer's earth terminal or conductor to an earth electrode, or to the supplier's protective conductor, is made.
Earthing terminal: a terminal fitted to equipment or to a device and intended for the electrical connection within the earthing arrangement.
Main earthing terminal: terminal (or busbar) that is part of the earthing arrangement of an installation that enables the electric connection of a number of conductors for earthing purposes.
Protective earthing: earthing of a point or points in a system or in an installation or in equipment, for purposes of safety.
Resistance of earth continuity conductor: use a resistance meter to measure the resistance of the earth continuity conductors between the consumer's earth terminal and the earthing terminals of all points of consumption and switches. The values shall not exceed those given in table 8.1 in SANS 10142.
Identification – colour AC and DC
The means of identification for an AC circuit may be by colours or by numbers, as follows:
• A neutral conductor shall be identified by black only.
• An earth continuity conductor shall be identified by the bi-colour green/yellow only, or by being bare. Green/yellow insulated conductors shall not be used as live conductors under any circumstances.
• A phase conductor shall be identified by a colour other than green/yellow, green or black.
• The colours may be applied at the ends of the conductor (of a multicore cable) by means of durable colour marking (e.g. insulating sleeves or by electrical insulating tape wound more than once around the conductor).
Where numbers are used, 0 shall indicate the neutral conductor. Note: where the purpose or the function of a conductor is apparent, marking is not required.
Where colours are used:
• The polarity of the positive conductor shall be identified by red only.
• The polarity of the negative conductor shall be identified by black or blue.
• The colours may be applied at the ends of a conductor by means of durable colour marking (e.g. insulating sleeves or by electrical insulating tape wound more than once around the conductor).
Where symbols are used:
• The polarity of the positive conductor shall be identified by the + symbol.
• The polarity of the negative conductor shall be identified by the – symbol.
• The symbols shall be applied at the ends of the conductor. The symbols may be applied by means of printed adhesive tape or cable markers.
AC and DC circuits: where an installation contains both AC and DC circuits and colour is used to identify the polarity of the DC conductors, polarity symbols described in (c) above shall be added at both ends of the DC conductors to distinguish them from the AC conductors.
Bonding: the aim of bonding is to bring all the bonded parts to the same electrical potential.
Bonding conductors: a bonding conductor shall:
• Have a nominal cross-sectional area of at least 2,5 square millimetres of copper, or equivalent.
• Be so arranged that it cannot be tampered with.
Continuity of bonding: test the continuity of the bonding between the consumer's earth terminal and all exposed conductive parts using a supply that has a no-load DC or AC voltage of 4-24 V, and a current of at least 0,2 A. The resistance shall not exceed 0,2 Ohms.
Protection: protective devices comprise one or more fuses or circuit-breakers. Sizing and selection of fuses and circuit breakers shall be according to the circuit requirements like load, cable current carrying capacity, short-circuit rating of the circuit, etc.
Circuit-breakers: circuit-breakers, disconnectors and switch-disconnectors shall not be mounted upside down. Horizontal mounting is allowed unless specifically prohibited by the manufacturer. Any deviation from the convention of connecting line to the top and load to the bottom of switchgear is not recommended. Reverse connection is allowed only if:
• It is specifically allowed by the manufacturer.
• Load and line are so marked that they are clearly visible during maintenance.
• Any contradictory marking is not visible after installation.
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