25 of 124  Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  Section 08: Electrical Works  MCC board  PLC board  Secondary board  Package  equipment board  Form 3b  Form1  Form 2  Form2 (wall or  frame type)  Form3b (standing  type)  Assembly design is to be of a modular type allowing the assembly to be broken down into sections for ease of  transportation and installation. The preferred module size adopted is 600x600 mm. Height of assemblies must  not exceed 2100 mm measured from finished floor level to the highest point of the assembly. Isolator handles,  control switches, push buttons, indicator lamps and instrumentation shall not be less than 300 mm and not more  than 1,900 mm above finished floor level. Width for terminal compartment will be minimum 400 mm in MCC  boards and 800 mm in PLC boards. All cable inlet and outlet for board will be made through IP 65 gland.  Solid barriers shall be provided to segregate each load compartment from other compartments and the busbar  chamber, to prevent objects falling into lower live compartments, and to restrict fault travel to other  compartments. The finish colour for assemblies shall be the manufacturers standard unless specified in the particular  specification.  Assemblies shall be regular shaped and rectangular, and where possible designed and constructed for floor  mounting over cable trenches.  Minor assemblies may be designed and constructed for wall installation. All cables must enter or exit  assemblies through a glanding plate provided with the appropriate sizes and types of cable glands (bushings)  from the bottom side of the assembly. Reference is to be made to service conditions above for the rating of components and equipment to be installed  in assemblies. Further equipment ratings shown on components and equipment must show the values applicable  for the ambient conditions.  8.7.3 General electrical requirements  Assemblies shall be rated for operation on a 400 V AC, 3 phase, 5-wire (TN-S), 50 Hz supply. Control voltages  shall be 230 V AC and 24 V DC. The size of the 24 V DC. supply unit is to be based upon actual consumers  connected plus future expansions of the plant.  All components shall function properly within a supply tolerance of -10 % to +10 % on the 400/230 V and -2,5  % to + 2,5 % on the 50 Hz frequency.  Signals to and from passive instrumentation shall be for analogue 4-20 mA, active or analyser instrumentation  communication system should be for Ethernet (TCP/IP) / analogue 4-20 mA , and for digital signals 24 V  DC.All component installed in assemblies shall be CE-labelled, and must be capable of withstanding the  dynamic and thermal stresses, without detriment, resulting from the prospective fault current.  The system of tripping devices for the circuit breakers shall be designed and set to ensure full selectivity. E.g.  short-circuit in any circuit shall be cut off by the breaker that is closest to the short.  The branch circuits shall be protected by means of circuit breakers. Fuses may not be used.  8_Vol3_d4 3_Section 8 electrical works_en_GIR rev6.doc 