This is the fourth in the FAQ series in which members’ questions are answered by the East/South Cape Regional Executive Committee and shared for the benefit of the broader electrical contracting industry in South Africa.
Before the East/South Cape regional meeting in February, a member objected to the “type of questions” in the agenda and said the answers could be found in the Code of Practice for the Wiring of Premises (SANS 10142-1). However, after discussion, it was agreed there is no such thing as a stupid question and that the practice of discussing labour, training, contractual or technical questions for the benefit of all members would continue.
The only stupid question is the one that isn’t asked …
Q: Can I replace a 36 W ballast with a 58 W ballast?
A: No, because although the light will work with the oversized ballast, the lamps will deteriorate quickly, and the ends of the tube will become blackened. It’s better to use a multi-range ballast.
Generally, with both magnetic and electronic ballasts, increasing the ballast wattage will under-run the lamp (with no major impact on life – but with reduced output). Conversely, reducing the lamp wattage will over-run the lamp (severely reducing lamp life – but increasing output). A number of ECGs are ‘multi-Watt’ but are still lamp specific. For example, most between T5 and T8 are not interchangeable and, within the T5 range, they are generally specific to either ‘high efficiency’ or ‘high output’. Some are also suitable for the long (24, 36 and 55 W) PL-type lamps. To ensure optimal fitting performance and lamp life, it’s crucial to ensure the specific lamp type and exact wattage being used is specified on the relevant ballast.
In a situation, PL 18 W downlights were fitted with linear 18 W ballasts (0.37 A instead of 0.22 A), and the lamps were severely overrun, and lamp life was severely impacted.
Interestingly, the linear 18 W ballast is suitable for T8 18 W tubes, PL 24 W-L, PL 26 W-D and 28 W 2-D lamps – whereas the Compact 18 W ballast is suitable only for PL 18 W-D lamps – highlighting the importance of the correct ballast/lamp combination.
Q: Is it legal for an Installation Electrician to work on the lights above the pumps at a filling station?
A: The light fittings above the pumps generally fall outside of the zone and therefore an IE or MIE can work on the lights, however a Single Phase Tester (SPT) cannot as the point of control in a fuel station is generally three-phase; if it is single-phase, then a SPT can also work on the lights. It is rare to see hazardous classified light fittings above pumps on a forecourt.
The CoC and test report ask if an area is hazardous – you say ‘yes’ and comment that the CoC will be issued by Contractor X. The Act allows an electrical contractor to sub-contract to a competent person in the same way that a builder subcontracts out his/her section of the electrical work to an electrical contractor.
No person other than a registered MIE may do electrical work in a hazardous location. An IE may do work outside of the Zoned areas, but you are responsible to ensure that it is indeed outside of the hazardous location and no part of your work can affect the hazardous location. Proof of evidence is everything in a hazardous location.
Page 2 of the test report asks, “Is any part of the installation a specialised electrical installation?” If ‘yes’ complete additional test reports (see 8.7). It doesn’t ask if the part of the installation you are working on is part of a hazardous location, it asks if any part of the installation is. EIR 9(4) says “Any person who undertakes to do electrical installation work shall ensure that a valid certificate of compliance is issued for that work.” Only a registered MIE may issue a CoC in a specialised electrical installation / hazardous location.
Q: The stage lights in a theatre are fed from a control unit that is plugged into a socket outlet. Is this legal?
A: SANS 10142-1 clause 7.10.1.6 Socket-outlet circuits supplied from a dimmer in any theatre, cinema or similar place of assembly do not need earth leakage protection, provided that
a) the circuits are derived from a safety supply, and
b) the socket-outlets are marked to indicate that they are on dimmer control.
