Non-Tariff Barriers

Non-Tariff Measure

NTM classification

B7: Product quality, safety or performance requirements 

Date when the measure came into force

16 December 1987 

Publication where the measure is specified

Government Notice 2286 (Government Gazette 10987) Of 16 October 1987 

Regulation where the measure is specified

Compulsory Specification For Earth Leakage Protection Units 

Country/Region applying the measure

South Africa 

The rationale of the measure

This specification covers earth leakage protection units (circuit-breakers) for use in domestic and industrial or similar electrical installations and connected to a source of alternating current supply operating at a frequency of 50 Hz, the neutral conductor of which is connected to the general mass of earth on the supply side, and subject to the following limitations:
(a) Maximum rated voltage.................................................. . . . . . 500v.
(b) Maximum rated current ....................... ................................ 100 A.
(c) Maximum rated earth leakage tripping current.. ........................30mA
(d) Ambient temperature ..................... ...................................... - 5 ̊C to +10 ̊C.

The earth leakage protection units covered by this specification are intended to reduce fire and electrocution
hazards caused by current leaking from line and neutral conductors to earth.
This specification does not cover earth leakage protection units intended for service under extreme operating
conditions such as continuous high atmospheric humidity, atmospheric pollution, mechanical vibration. mechanical shock, and excessively high or low temperatures. 

Coded list of objectives

X: For purposes n.e.s. 

Description of the measure

3. DESIGN AND CONSTRUCTION.
3.1 STANDARD OF WORKMANSHIP AND FINISH: All work shall be properly executed and finished and shall be so arranged as not to constitute a hazard.
3.2 MOULDED CASE: The operating mechanism of an EL circuit-breaker shall be contained in a moulded case made of a non-combustible insulating material that will not allow the escape of flame or molten metal through the openings surrounding the operating toggle.
3.3 PROTECTION.
3.3.1 Live parts of an EL circuit-breaker intended for open surface mounting shall be protected against inadvertent contact by means of acceptably strong covers of insulating material.
3.3.2 Live parts on the underside of an EL circuit-breakers designed for mounting on a surface shall-
(a) be covered by a shield or barrier of insulating material; or
(b) be countersunk at least 3 mm below the surface of its base and covered with a waterproof insulating sealing compound that will not flow during any of the tests specified in Section 6 ; or
(c) have a minimum clearance of 6 mm from the mounting surface and be riveted, upset or otherwise acceptably prevented from loosening.
3.4 CLEARANCES AND CREEPAGE DISTANCES: All clearances and creepage distances shall be as large as is
practicable and, in order to break the continuity of conducting deposits that may form, creepages shall, wherever practicable, incorporate ridges.
3.5 MOUNTING: Each EL circuit-breaker shall have at least two holes for mounting purposes or an alternative method of mounting that will ensure acceptable stability.
3.6 MODE OF OPERATION
3.6.1 An EL circuit-breaker shall be arranged for manual closing and opening and for automatic stripping. The mechanism shall be trip-free.
3.6.2 The actuating mechanism shall be such that when an EL circuit-breaker is mounted in the normal manner, the contacts cannot close by themselves as a result of failure of the mechanism,
Note: The mounting of an EL circuit-breaker on a vertical plane with its major axis vertical or
horizontal shall be considered as mounted in the normal manner.
3.6.3 The tripping of an EL circuit-breaker under any conditions within its ratings shall not cause the contacts that break the circuit to bounce or show any tendency to reclose.
3.7 ARCH SHIELDS: Means shall be provided to ensure that when a multi pole EL circuit-breaker operates, there is no arcing between the poles.
3.8 TRIP INDICATION: An EL circuit-breaker shall be so designed that when it has been tripped, a clear indication to that effect is visible to the user.
3.9 TERMINALS
3.9.1 An EL circuit-breaker shall be provided with suitable terminals for the connection of copper conductors of the size given in column 2 of Table 1, appropriate to the current rating of the EL circuit breaker. The terminals of an EL circuit- breaker with an intermediate rating shall accommodate conductors of the nominal cross sectional area specified for the next higher current rating.
3.9.2 Terminals shall be so designed that they do not allow the conductors to be displaced and are not themselves displaced in a manner detrimental to the operation of the EL circuit-breaker or the effectiveness of the insulation (i.e. the minimum prescribed values for clearances and creepage distances specified in 3.3.2 (b) and ( c ) shall be maintained under all conditions of normal operation of the EL circuit-breaker).
3.9.3 Each terminal for the connection of an external conductor shall be so arranged that it is readily accessible under the intended conditions of use, and an earth terminal (when provided) shall, in addition, be-

(a) suitably protected against corrosion,
(b) permanently and indelibly marked with the symbol (see Regulation), and
(c) of such a size as to accommodate a conductor that complies with the provisions for earth continuity conductors of SABS 0142 ‘The wiring of premises’
3.9.4 A wiring terminal need not be such as to accept a conductor directly, i.e. without some suitable termination being applied to the conductor, but where a terminal is intended to accommodate a stranded conductor, means shall be provided to prevent the conductor wires from spreading.
3.9.5 Each wiring terminal screw shall thread into metal and shall have a smooth clean-cut thread that is free from burrs. The end of the screw shall be so shaped that it will not damage the conductor. Except as allowed below, iron and steel, unless present as a constituent of an alloy that is inherently corrosion resistant, shall not be used for terminals.
3.9.6 Terminals of the type in which the external connecting conductors make direct electrical contact with the pole of an EL circuit-breaker and that are not dependent upon to carry the main current of the EL circuit-breaker, may be of iron or steel that has been plated in an acceptable manner with copper, nickel, cadmium, silver or zinc.
3.10 EARTHING: Provision shall be made for the earthing of any exposed metal parts of an EL circuit-breaker that may become live if the insulation of any part of the EL circuit-breaker becomes defective (see also 3.9.3).
4. ELECTRICAL AND PHYSICAL REQUIREMENTS.
4.1 RATINGS: Each EL circuit-breaker shall be rated in terms of voltage, current, breaking capacity or short-time withstand current, and number of poles.
(a) The rated voltage shall not exceed 500 V and the rated load current shall not exceed 100 A.
(b) The breaking capacity shall be 2,5 kA or 20 times the value of the rated current, whichever is the greater.
(c) The rated earth leakage tripping current of an EL circuit breaker shall, subject to a tolerance of+0/-50%, be 5, 10 or 30 mA, as applicable.
Note: The values for the rated earth leakage tripping current are recommended by the International
Electrotechnical Commission.
4.2 INSULATION RESISTANCE: When determined in accordance with 6.3, the insulation resistance of an EL circuit-breaker shall be at least 10 MΩ.
4.3 UNDERVOLTAGE RELEASE.
4.3.1 When so required, an EL circuit-breaker shall be provided with an undervoltage release.
4.3.2 An EL circuit-breaker having an undervoltage release shall, when tested in accordance with 6.4, open even on a slowly falling voltage ( 1 % per second) at a value of between 70 % and 35 % of the rated voltage of the undervoltage release.
The undervoltage release shall prevent closing of the circuit-breaker at a voltage below 35% and shall not prevent closing at and above 85% of the rated voltage of the undervoltage release.
4.4 SHUNT RELEASE.
4.4.1 When so required. an EL circuit-breaker shall be provided with a voltage-operated shunt release having a specific voltage rating or range of voltage ratings.
4.4.2 An EL circuit-breaker provided with a voltage-operated shunt release shall, when tested in accordance with 6.5, operate on both 70 % and 120% of the rated voltage of the shunt release.
4.5 OVERCURRENT RELEASE.
4.5.1 General:
4.5.1.1 When so required, an EL circuit-breaker shall be fitted with an overcurrent release.
4.5.1.2 The overcurrent release shall be of an adjustable or non-adjustable time-delay type or a non-time-delay type.
4.5.1.3 The current-time characteristic of an EL circuit-breaker shall be that assigned by the manufacturer and marked on the EL circuit-breaker [see 5.1 (k)].
4.5.2 Time-delay type:
4.5.2.1 An EL circuit-breaker having a non-adjustable time-delay release shall carry its rated current continuously without tripping but, when tested in accordance with 6.6, shall release automatically within the periods given in Table 3, appropriate to the rated current of the EL circuit-breaker.
An adjustable time-delay release shall be such that, when it is adjusted to its maximum setting, the EL circuit-breaker will comply with the requirements of 4.5.2.1
4.5.3 Non-time-delay-type. An EL circuit-breaker having a non-time-delay release shall carry its rated current continuously without tripping and, when 135 % of rated current is applied, shall release instantaneously and the arc shall be extinguished within 0,1 second.
4.6 OVERLOAD: When tested in accordance with 6.7 or 6.8, as applicable, an EL circuit-breaker shall show no sign of electrical or mechanical failure and no welding, undue burning, or pitting shall occur at the contacts.
4.7 TEMPERATURE RISE: When determined in accordance with 6.9, the temperature rise of the insulating materials and of each of the parts of an EL circuit-breaker shall not exceed the relevant value given in Table 4.
4.8 MECHANICAL STRENGTH : When tested in accordance with 6.10 , an EL circuit-breaker shall show no signs of cracks or permanent deformation.
4.9 PERFOMANCE OF AN EL CIRCUIT –BREAKER UNDER EARTH FAULT CONDITIONS: When an EL circuit-breaker is tested in accordance with 6.11, the unit shall trip, the butter muslin shall not be ignited, and the fuse shall not rapture. The EL circuit-breaker shall, within 24 hours after the test be capable of operating successfully at the rated earth leakage tripped current.
4.10 BREAKING CAPACITY (FOR AN EL CIRCUIT-BREAKER FITTED WITH AN OVERCURRENT RELEASE)
4.10.1 (a) An EL circuit-breaker shall be capable of once breaking and once making-and –breaking a circuit adjusted for the prospective current with the relevant power factor given in Table 7, appropriate to the breaking capacity of the EL circuit- breaker.
(b) The inherent resetting time of an EL circuit-breaker shall not exceed 15 minutes.
4. 10.2 When an EL circuit-breaker is tested in accordance with 6.12-
(a) it shall show no sign of electrical or mechanical failure;
(b) the butter muslin placed over the operating toggles shall not be ignited;
c) the average value of the power-frequency recovery voltage shall be equal to a value corresponding to 110% of the rated operational voltage (see 6.12.1 (b) )occurring across the terminals of a pole of the EL circuit-breaker immediately before the flow of the test current, and this voltage shall be maintained for a period of at least 0.1 seconds after extinction of the arc;
Note: This may require that the applied voltage be increased but the tolerance on the prospective peak-making current shall not be exceeded without the consent of the manufacturer.
(d) there shall be no connecting metal parts to the neutral of the a.c power supply shall not rupture;
(f) the EL circuit-breaker shall still comply with the requirements of 4.5.2 for 200% of the rated current, or 4.5.3 as applicable ; and
(g) the EL circuit-breaker shall still be capable of withstanding, for one minute without breakdown, attest voltage of magnitude as given in Table 7, appropriate to the rated voltage of the EL circuit-breaker.
4.11 SHORT-TIME WITHSTAND CURRENT (FOR AN EL CIRCUIT-BREAKER NOT FITTED W AN
OVERCURRENT RELEASE): When tested in accordance with 6.13, an EL circuit-breaker that is not fitted with an overcurrent release shall be capable of once making and carrying for a period not exceeding 40 ms the prospective current appropriate to the specified rated short-time withstand current (not less than 2,5 kA)[see 5.1 (j)), the power factor being that applicable for the breaking capacity class of the same prospective current (see Table 6).
Note: The test shall be conducted with a preceding circuit-breaker or fuse in the circuit, when so requested. Such protection shall be supplied.
4.12 PERFORMANCE OF AN EL CIRCUIT-BREAKER UNDER EARTH LEAKAGE CONDITIONS. When an EL
circuit-breaker is tested in accordance with 6.14,6.15 and 6 . 1 6-

(a) the EL circuit-breaker shall on each occasion trip positively;
(b) under no conditions shall the EL circuit-breaker trip when the value of earth leakage current is less than 50 % of the rated value;

(c) no value of the operating time for a suddenly applied earth leakage current shall exceed the applicable value given in Table 5;
(d) all five values of earth leakage current in each test for a gradually applied earth leakage current shall be between 0,5 I Δn and IΔn, when I Δn is the rated earth leakage tripping current; and
(e) no value of the operating time recorded while the EL circuit-breaker is closed on the rated earth leakage current shall exceed the applicable value given in column 2 of Table 5

4.13 TEST AND RESET BUTTONS: Every EL circuit-breaker shall have a test button that is easily accessible when the EL circuit-breaker is mounted in its normal position, and by means of which the correct functioning of the EL circuit-breaker may be tested. The test button shall preferably be of a light colour (red or green shall not be used). The test facility shall be so connected in the circuit as to ensure that the sensing device, the amplifier, and the circuit-breaker mechanism are all tested for failure or deterioration. The test facility shall be so designed that a current equivalent to 125-175 % of the rated earth leakage tripping current flows through the sensing device when the test button is operated with the EL circuit-breaker energized at its rated voltage. Where necessary, a reset button shall be provided but this shall not inhibit the functioning of the EL circuit-breaker. The test and the reset
buttons shall be identified in accordance with 5.1 (d).
When tested in accordance with 6.17, the test button shall show no signs of mechanical failure and the EL circuit breaker shall still trip when the test button is operated.

4.14 DESENSITIZATION CAUSED BY LOOP RESISTANCEOF A NEUTRAL TO EARTH FAULT: When tested
in accordance with 6.18, and EL circuit-breaker shall mp before the earth leakage exceeds twice the rated value.
4.15 TRIPPING CAUSED BY CAPACITIVE CURRENTS: When tested in accordance with 6.19, an EL circuit breaker shall not trip more than five times.
4.16 NON-COMBUSTIBILITY: When tested in accordance with 6.20, materials that are required to be non-combustible shall be incapable of giving off flammable vapours. 

Reference of the measure

Regulations 3 to 4.16 

Measure also domestic

Yes 

Products affected by the measure.

Description

Earth leakage protection units (circuit-breakers) 

Countries/Regions affected by the measure.

Description

All countries