The history of the Wiring Code and how it applies to old installations
In South Africa, there have been four Wiring Codes since 1922, which influence the interpretation and application of the rules in today’s code of practice. This is important when considering the statement on page 3 of SANS 10142-1 Edition 2: “The edition of the standard that was applicable at the date of erection of an electrical installation is to be considered the edition defining the requirements applicable to that particular installation.”
Knowing the history of the Wiring Code helps electrical contractors make informed decisions when it comes to old installations and understanding what is compliant, what is not, and what is reasonably safe.
In Part 2 of this the series, “The history of the code and how this applies to old installations”, Chris Koen will explore how changes in the code have influenced isolators for domestic water heaters.
When do you have to install an isolator for storage type domestic water heaters?
- For all new geyser installations.
- When the geyser is replaced.
- When, for some reason, the circuit must be re-routed.
- Upgrading the element (for example 1,5 to 3,5 kW).
- When two geysers are connected in parallel.
- When you must change the element/thermostat and the wires have overheated and they are now too short for re-connection.
- When ripple relays or load-shedders are installed in the circuit.
- When geysers are replaced by an instantaneous water heater (not more than 3,5 kW or ± 16 A if fed from a socket-outlet).
Looking at the points above, it will be necessary to either install an isolator or a socket-outlet within 1,5 m of such a geyser, or in the distribution board if the switch disconnector (isolator) can be locked in the open position. This is a requirement of the current Wiring Code, SANS 10142-1 Edition 2 2017 clause 6.16.1.4. Remember, if you connect the geyser by means of a socket outlet, it must not exceed 1,6 A.
In terms of the Electrical Installation Regulations of 2009, which are regulations in the Occupational Health and Safety Act (Act 85 of 1993), sub-regulation 7(3) and sub-regulation 9(2) state, inter alia, that the requirement to issue an electrical Certificate of Compliance (CoC) shall not apply to the electrical installations existing prior to the coming into force of the current standard but that if any additions or alterations are effected to such an installation after such date, a CoC shall be issued for the whole installation, whereafter further CoCs will only be needed for any additions or alterations.
Therefore, based on the EIR, if you are carrying out an inspection on a house that existed before the current edition of the standard and no alterations or additions have been made to the installation, you need only certify the installation as reasonably safe (i.e. free from any hazard).
Now that we have hopefully created a better understanding of when to install an isolator for a geyser, the rest of this article should be regarded as guidelines in helping to decide whether the circuit of a geyser is reasonably safe when certifying on the CoC/Test Report (Section 4, Inspection and Tests) that the installation complies with the general safety principles of the Code.
When do you not have to install an isolator for a geyser?
Please note that the following information is given only as a guide to assist you in determining which standard or code applied at the time the geyser was originally installed. It is, of course, up to the registered person doing the inspection to establish whether any alterations have taken place to the original geyser installation and, if so, when such changes took place.
The Red Book, 1940: Standard Regulations for the Wiring of Premises
This book was printed by the South African Institute of Electrical Engineers (SAIEE).
Regulation 111 – 15 (b) “Water heaters”
“All water heating apparatus directly connected to the installation shall be provided with an approved type of automatically operated thermostatic switch or switches which shall be so adjusted as to disconnect the supply of electric energy when the temperature of the water reaches 32ºF below boiling point.”
Regulation 211 – 15 Installation of water heaters
“Water heating apparatus shall be arranged on a circuit or circuits separate from the other of the installation.
Electric water heaters shall be controlled at the distribution board by a metal-clad multipole switch.
The conductors shall be led from the outlet from the fixed wiring to the cover of the heating element terminals by means of flexible metallic conduit.”
One important point to consider is that, at that time when electric water heaters were installed, they were not generally used in domestic installations. In those days, the ordinary household usually had coal or wood-type water heaters, and some still exist today.
Next, we go to the rules that were applicable in the Blue Book, which cover the period from 1950 to 1978.
The Blue Book 1950 – 1978: Standard Regulations for the Wiring of Premises
This book was printed by the South African Bureau of Standards (SABS).
Clause 708 Water-heaters
“Terminals of the heating elements of water-heaters shall be provided with a cover of approved design held in position by screws or nuts other than wing nuts.
“Except in the case of the electrode water-heaters, all water-heating apparatus [The following words were inserted in the Nov 1976 amendments: “of the storage type”] directly connected to the installation shall be provided with an approved type of automatically operated thermostatic switch or switches which shall be so adjusted as to disconnect the supply of the electric energy when or before the temperature of the water reaches 32ºF below boiling point. [The following words were inserted in the November 1976 amendments: “except for approved water-boiling vessels.”]
Note that, at this point in history, there was still no requirement for an isolator except in the case of electrode water heaters (Regulation 709) (not dealt with in this article).
It stated that all water-heating apparatus shall be of a type that the water is not in direct contact with that portion of the element, which is live.
“Any electrically operated water-heating apparatus in which steam is continuously generated at a pressure above that of the atmosphere, such as boilers or sterilisers, must comply with the regulations framed under the Factories, Machinery and Building Works Act, 1941, or any act in substitution thereof, and in addition must be provided with a pressure-actuated or similar approved type of temperature regulator.”
Today, we have the Occupational Health and Safety Act, Act 85 of 1993 Vessels Under Pressure Regulations”.
“Unless otherwise approved, the cables shall be led from the outlet from the fixed wiring to the water-heater terminal through metallic conduit. It shall be possible to remove the cover over the terminals without disturbing the connections or the conduit.”
New amendments to these regulations were inserted into the Blue Book during 1969 – 1976 and they read as follows:
“Water-heaters of the non-storage instant-heat type may be installed only if approved by the engineer for each particular installation unless approval has been given for his supply network generally.”
Remember that the municipal engineer had the final say in what he wanted in his electrical network. We also know that inspectors did this task for and on behalf of municipal engineers.
“Every non-storage instant water-heater must be installed as a fixed appliance and shall be controlled by a switch or isolator, fixed apart from the water-heater, but within easy reach of a person standing beside the water heater, and connected so as to disconnect both phase and neutral in the case of a single-phase supply, and all phases in cases where there is more than one phase in the supply to the water-heater. Flexible conduit may not be used and cables must be armoured.
In addition to the bonding the conduit or armouring to the nearest cold-water pipe, a separate earth continuity conductor must be provided and run in the conduit or cable and connected to the main earth system.
“Free flow water-heaters shall have an indelible label over the removable cover giving access to electrical connections with the words,‘Isolate before removing cover.”
Chris Koen, ECA regional director, Highveld
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