Electricity + Control April 2016

ELECTRICAL PROTECTION + SAFETY

References [1] SANS10199. 2010. The Design and installation of earth electrodes. [2] IEC 62305-3. 2006. Protection against lightning – Part 3: Physical damage to structures and life hazard. [3] SANS/IEC 62651. 2013. Nuclear power plants - In- strumentation important to safety - Thermocouples: characteristics and test methods.

- Proper site assessments must be carried out including the carry- ing out of various soil resistivity surveys, appraisal of the soil`s corrosiveness and the determination of the various external factors that can cause corrosion of the earthing and lightning protection components. - Quality engineering and properly designed protection systems must be employed taking into account the various corrosive elements that may exist on the site and the correct combination of the various LPS conductors. - Additional protectionmeasures such as the use of anti-corrosive tape on the belowground con- nections should be installed on sites that could be corrosive and where clamped or crimped below ground connections exist. - Bi-metallic joints must be installed when two dis- similar metals are joined. - Copper parts should never be installed above galvanised or aluminium parts unless those parts are provided with protec- tion against corrosion. Extremely fine particles are shed by copper parts which result in severe corrosive damage to galvanised parts even where the copper and galvanized parts are not in direct contact. - LPS should be constructed of corrosion-resistant materials such as copper, aluminium, stainless steel and galvanised steel.

Trevor Manas started his lightning protection career at Pontins in 1991. After spending some years in sales, he was promoted to the position of director in 1996, in charge of ensuring the company`s compliance with the earthing and lightning protection codes of practice. In 1999, Trevor became the managing director of Pontins. In 2013, Pontins formed a partnership with DEHN Africa. Enquiries: Email trevor@pontins.co.za

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ELECTRICAL PROTECTION + SAFETY

Custom built E Houses… cost effective alternatives

substations or E-Houses has opened up numerous possibilities including the ability to completely customise the unit accord- ing to process and plant requirements,” Richards explains. Specifically designed for this underground application in a coal mine, the E-House was designed with sev- eral specific parameters taking precedence. Underground height restrictions meant that the structure itself had to be lower than usual but would still need to accommodate all necessary electrical infrastructure and allow for sufficient headroom for cooling. Richards says it is testimony to Shaw Controls’ mechanical design capability that its engineers were able to design such a low profile steel structure that could house all the equipment and still maintain the requisite internal clearances.

Custom built E-Houses offer a rapid and far more cost effective alternative to the build- ing of brick and mortar substations, and this is especially true in an underground application.This is one of the reasons why Zibulo Colliery contracted Shaw Controls , a division of Zest WEG Manufacturing, to design and manufacture an E-House for its operation in the Mpumalanga coalfields. Containerised electrical control installations in underground applications are not new. Bevan Richards, Chief Operations Officer of Shaw Controls, says the concept was first used during the sinking of many of South Africa’s gold mining vertical shafts when ISO marine containers were equipped with mimic panels and other ancillary equipment. “However, the evolution and devel- opment of pre-manufactured electrical

Another important criteria that had to bemet was the voltage being used on the mine.The majority of mines use 525 Volts, but in the instance of Zibulo Colliery the voltage being used is 1 000Volts.This required special de- sign work on both the Motor Control Centre (MCC) and theVariable Speed Drive (VSD) to ensure safe operation at 1 000Volts. Enquiries: Kirsten Larkan.Tel. +27 (0) 11 723 6000 or email marketing@zestweg.com

Electricity+Control April ‘16

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