Meter Cup Board (MCB) for Single Phase Energy Meters

Transcription

1 DAKSHIN HARYANA BIJLI VITRAN NIGAM LIMITED SPECIFICATION NO.S-61/DD-161 Meter Cup Board (MCB) for Single Phase Energy Meters Issue of month:april,2006

2 TECHNICAL SPECIFICATION IN RESPECT OF METER CUPBOARD (MCB) FOR SINGLE PHASE ENERGY METERS 1. SCOPE This specification covers the design, manufacture, inspection, testing and supply of MS sheet. Meter Cup Board (MCBs) for housing single phase energy meters for electric connections of General category i.e. Domestic & Commercial connections. 2. CONSTRUCTIONAL AND TECHNICAL PARTICULARS : 2.1 The MCBs shall conform to drawing attached as per Annexure-I to IV. It shall be dust and vermin proof for housing single phase energy meters of any make. The internal dimensions of MCB shall be 300mm x 250 mm x 160 mm ( i.e. height x width x depth). 2.2 The MCB shall be made from 20 SWG MS sheet by the following method: Deep Drawn Method: The base and cover of the MCB shall be individually in one piece without any welding except for fixing of the accessories like hinges, clamps, handle etc. which shall be spot welded. The cover of MCB shall be fixed on two tamper proof inside hinges not visible from outside. The hinge pin diameter should be minimum 3mm, Hinges shall be made from min. 1.6mm MS sheet. The door of MCB shall open from right to left by minimum 90. The collar of the door (cover) in closed position shall rest on the collar of the body (base) of MCB. The collar of the door shall overlap the collar of the body of MCB by minimum 8mm. The collar of the body shall be provided with good quality rubber gasket lining of min. 3mm thickness. Thickness of rubber lining shall be such that it provides proper sealing between the cover & base of MCB to avoid penetration of dust and ingress of water. Rubber lining should be fixed with suitable adhesive so that the same does not get removed by itself on opening of the door. Two No. sealing screwswith rubber washer shall be provided to seal & hold the door and body of MCB. Head of sealing screws should have hole of 3mm. The fixing arrangement of the sealing screws shall consist of min. 1.6mm thick strip (L-shaped) welded from inner side of the body & another strip having

3 U-shaped end with 3 mm holes welded from inner side of door of the MCB. The length of the extended portion of the strips shall be such that the sealing screws in tightened position are at a distance of about 5 mm from end of the collar of the cover. 2.3 All the steel sections used in fabrication shall be carefully leveled and straightened before any works is done on them. No rough edges shall be permitted anywhere through out the work. The material of MCB shall be capable to withstand mechanical, electrical and thermal stresses as well as the effects of humidity, which are likely to be encountered during its service. All the spot welding work shall be done carefully so as to avoid over heated spots, cavities, porosity burns and dents etc. The surface should be properly cleaned before welding and slag removed after welding. 2.4 A viewing window opening of the size 100x90 mm as indicated in the drawing shall be provided about 40mm below top edge of MCB to facilitate taking of meter readings. Viewing window shall be provided with toughened glass of 5mm thickness. Glass shall have scratch proof DHBVNL logo on the right side top corner of the glass. This glass shall be fixed from inside of the cover of MCB, with single piece drawn metal frame (Glass Holder) made of 20 SWG MS sheet fixed with min. four screws. Glass holder shall have rectangular cuttings as per details shown in Annexure-III. The size of toughened glass shall be 120mm x110 mm so as to provide minimum overlap of 10mm. This glass has to be fitted with a wrap around single piece rubber ring without joint having minimum depth of 8mm made from good quality rubber so as to with stand weather effect. 2.5 A handle of minimum 60mm length and 10mm width and 20 SWG sheet thickness should be provided for opening and closing of the cover at the place as shown in the drawing. 2.6 The mounting arrangement of the meter shall be as shown in the Annexure-II. It should be raised from the base of MCB body by 35mm (minimum). The mounting arrangement shall have 3mm thick adjustable slotted SRBGF sheet(synthetic Resin Bonded Glass Fiber Sheet) flat fixed with screws on the mounting arrangement.adjustable slotted flat shall be provided with two MS

4 screws (M4 x 25mm length) with nuts.and one screw ( M4 x 12mm length)shall be provided at upper point with SRBGF Strip for meter hanger. 2.7 Sealing arrangement as shown in drawing with a sealing screw of 5.0 mm diameter shall be provided for sealing of MCB.Head and Body of sealing screw shall have a hole suitable for sealing wire. 2.8 The MCB shall have Self Locking (Push fit type)arrangement. The locking should be such that,once the box is closed it cannot be opened without breaking the box or glass. 2.9 Four Nos. fixing holes of 6.5 mm diameter at the back of surface of MCB shall be provided to fix the MCB at flat wall or surface. For fixing of MCB 4 No. 5mm diameter 40mm long pan head self taping screws and washers shall be provided by the supplier with every MCB 4 Nos. plastic fixing plugs of 50mm length suitable for self-tapping screws shall also be provided Nos. holes with superior quality plastic cable glands of internal diameter of 15mm each for incoming and outgoing cables shall be provided at the bottom of the MCB.Plastic Glands shall be properly fixed on the box such that the same does not get removed from the box.glands shall be made such that internal diameter of glands provided for cables should be closed with the film of not less than 1mm thickness.cable will go through the glands by piercing the film of the glands MCB shall be adequately protected against rust, dust water and corrosion both from inside and outside. The MCB shall have smoke grey shade on outside and white on inside. The MCB shall be powder coated. Powder Coating: The surface of the MCB shall be properly pre-treated and cleaned in 7 tank process (degreasing,water rinsing,de-rusting,water

5 rinsing,phosphating,water rinsing,passivation) and shall be applied with a powder coating of suitable thickness on outer side and inside the box Earthing bolt of diameter 6 mm with nut and washer shall be provided in the threads of L-shape clamp welded to main body on left side All the screws and washers shall be properly zinc plated The tolerance permissible on the overall dimensions and weight of the MCB shall be (+/-) 2%. 3. DEGREE OF PROTECTION: The MCB shall comply with the requirement of IP-52.The MCB shall be fully type tested as per IP-52.All the type tests shall be carried out from the Govt approved laboratory which are accredited by the National Board of testing and calibration laboratories (NABL) of Govt of India.The type test reports shall be furnished along with the bid,failing which the tender shall not be entertained and liable to be rejected.the type test report shall not be older than 3 years on the date of opening of Tender part-i. 4. DRAWING/SAMPLES One complete set of detailed dimensioned drawings of each offered item shall be submitted along with tender.enclosed drawings are only for general arrangement purpose. One sample of MCB as per specifications shall be submitted along with tender and any tender not accompanied with the sample shall be rejected out rightly.the samples being furnished shall be new. 5. MARKING: DHBVNL insignia as shown in Annexure-IV shall be embossed on the MCB. The word DHBVNL shall be embossed on the Meter Cup Board. A notice with wording that There should be no cable joints inside the cabinet should be printed in Red on the pocket of the meter cup Board. A notice

6 in Hindi with wording that should also be got printed on the pocket of the meter cup Board. 6. INSPECTION: The manufacturer shall give minimum 15 days advance notice about readiness of material at his works. The material shall be inspected for conformity with DHBVNL specification before the same is accepted. DHBVNL may also carry out stage inspection of the MCBs before powder coating. For this the manufacturer shall intimate the manufacturing schedule in advance. 7. PACKING : The MCB shall be suitably packed in 3 ply corrugated boxes in order to avoid damage in transit, handling, storage and further transportation from store to field. 8. SAMPLE : The tendered shall submit one sample Meter Cup Board along with tender. The tender of the firm shall only be opened if sample of MCB has been submitted as per NIT. In case order is placed on a firm the MCBs shall be supplied as per sample. No change in design shall be allowed in supplies. Superintending Engineer/P&D, DHBVNL,Hisar.

7 ANNEXURE-IV D H B V N L DHBVNL INSIGNIA TO BE EMBOSSED ON THE DOOR OF MCB