CPA Bulletin

42 CPA Bulletin > November 2024 www.cpa.uk.net SPECIAL INTEREST GROUPS: 2 CIG/TCIG Open Meeting at Vertikal Days Assisted by CPA Training and Safety Manager Rob Squires, the openmeeting was jointly organised by two of the CPA’s Special Interest Groups - namely the Crane Interest Group (CIG) which is chaired by Peter Gibbs, CEO of Ainscough Crane Hire and the Tower Crane Interest Group (TCIG) chaired by Dave Holder, European Operations Director of Wolffkran. The open meeting afforded an opportunity to discuss key topics and issues affecting the crane sector, such as abnormal loads and embargoes, electrical supply issues and updated Network Rail guidance regarding the use of cranes beside railways. Meeting attendees were warmly welcomed by Steve Mulholland who has recently been appointed CPA Chief Executive Oficer. Steve has a great deal of experience in the sector, having previously been the CPA Chair and a CPA Council Member for over 10 years. Steve, who formerly ran his family business Mulholland Plant Services, underlined his commitment to the CPA Special Interest Groups in his introduction. TCIG Chair Dave Holder introduced Craig Hook who is a Specialist Consultant to the CPA with over 33 years’ of experience in construction, and 21 years’ experience in cranes and lifting, working for Sir Robert McAlpine. Craig delivered the first presentation of the day which related to tower crane electrical supply issues and a subsequent update to Technical Information Note (TIN 036). Craig gave some background information as to why the guidance needed to be updated, whereby a Tower Crane Technician was working on a tower crane that had an electrical fault, but the Residual Current Device (RCD) had not tripped and the technician was injured. The RCD was the wrong type which had the wrong sensitivity to the fault current. Craig explained that the use of variable-frequency drive-controlled motors on most tower cranes and construction hoists reduces starting currents and, consequently, the required capacity of the power supply – however they have special requirements of the type of RCD to be used. The presentation underlined that most tower cranes and many hoists now use inverters to convert the incoming power supply from Alternating Current (AC) to Direct Current (DC) so that the speed of motors is controlled accurately using frequency converters. This allows energy saving, speed regulation and motor speed accuracy along with low-speed high torque and stepless changes. However, because the DC output from frequency converter is at such a high frequency, not all types of RCD will detect a fault. This is a factor in equipment within the tower crane circuits as well as in generators, resistor banks, regenerative braking, power storage and any other areas which also work in DC. Many tower crane OEMs are specifying type ‘B’ RCDs as these detect a fault that that has a high, smooth DC voltage content. Craig advised attendees to provide good earth bonding (electrical) and lightning protection as per the tower crane’s manufacturer requirements. Craig’s second presentation of the day focused on guidance on the tendering, management and operations of tower cranes, and in particular the introduction of a new document, namely TCIG 2404 which is designed for use by tower crane suppliers and rental customers. TCIG and CIG have sister documents supporting the tendering, management and operation of cranes, and to ensure that contracts start off from a clear understanding of needs and responsibilities, the new document makes clear what offers include and allows a standard assessment process. The overall aim is to standardise the questions asked by clients and to allow suppliers to prepare properly and demonstrate good practice. The third presentation of the meeting was focused on updated guidance to Network Rail rules with regards to the use of cranes beside railways. Craig explained that Network Rail document CIV0063 Cranes and Plant Beside Railways had been updated and Over 150 people attended an openmeeting hosted by the Construction Plant-hire Association (CPA) at Vertikal Days at Newark Showground.