CONSTRUCTION 

 

Housing 

 

  1. These are indoor type-unless otherwise specified; totally enclosed; vermin-proof.(Dust proof construction available when specified) rigid construction. All sides protruding type. (Flush type available when specified). Front of board-operated.

  2. These will be free standing and floor mounting type.

  3. Gaskets will be non-deteriorating type (Neoprene Rubber and/or rubberised cork sheets) between all covers, doors and the frame work/body.

  4. Vents and louvers will be provided with close mesh screens (plated) for vermin proofing.

  5. Doors will be hinged type, vertically standing and with quick release fasteners.

  6. Gland plates will be robust and un drilled. (These will be drilled and fitted with cable glands if specified).

  7. Steel Work

    8.

Thickness of sheets used = 14 SWG or 2 mm.

Thickness of base channel or structural = 3 mm min

 

Components

 

  1. Bus bars will be of adequate cross section in copper. They will be air insulated with proper clearance between lines and between phases and earth. Main bus bars will be properly screened to prevent accidental contact, when the panel is opened for inspection.

  2. Switch-fuse units/isolators.

    3. These will be of heavy duty (as per IS-4047) quick-make, quick-break type.

  3. Fuses.

    4. All L.T. Fuses will have an ISI Mark. They will be mounted on fuse bases. They will be easily approachable.

  4. Contactors will be of the air brake, magnetic type. They will be vertically standing.

  5. Push buttons will be generally shrouded type (Mushrooms type available when specified). There will be one NO and one NC contact on each push button. 'STOP' push button will have a 'stay-put' feature. Color code will be as per IS-6875-Part-II.

  6. Indicating lamps will have 100 volts bulbs in series with ballast resistors.

  7. Control Transformers when used, will be double wound, dry type and will have good regulation (5 % or less to cope with in rush current of contractor coils.

  8. Space Heaters:

    9.

Anti condensation space heaters metal enclosed, low surface temperature, suitable for 240 V,1 phase supply along with a switch and fuse will be provided in each panel.

Item 2,3 and 4 will be suitably derated for continuous capacitor duty.

The makes of all the above items will be L& T or Siemens (Other makes will be provided when specified).

Wiring

 

  1. All internal control wiring will be carried out with single core, PVC insulated copper conductor-flexible with standard wires.

    2. Minimum size of control wiring will be in 1.5 Sq. mm2.(2.5 sq. mm will be provided when specified).Identification ferrules will be provided for all wires at each connection point as per IS-5578-Dependent, local and marking.

  2. Power Wiring may be done in copper sections (Rectangular/circular). Covered with PVC tape/sleeve. (It may also be done in PVC insulated copper cables with cable lugs at each end when specified). The conductor cross section will be suitably derated for capacitor duty. No ferrules/identification tags will be attached to the power wiring.

    3.

Earthing

 

Sheet metal panels-on which live parts are mounted. Including doors and capacitors when enclosed in a panel, will be firmly connected into two separate earthing points brought out at two convenient locations on the outside of the panel.

The earthing may be achieved through one of the followings:-

Capacitors Assemblies and Door through distinct copper links (bare).

Other sheet metal parts-through continuity in welding: tapped and unpainted holes with bolting connections: optionally through copper wires.

Minimum copper conductor size will be 6 Sq. mm. There will be two such conductors per specified member.

Hardware

 

All the M.S. Hardware will be electro-galvanised and passivated. Brass hardware will not be plated to distinguish it from plated M.S.Hardware.

Painting

 

All metal parts will be thoroughly cleaned degreased and given the following coats:

One coat of cold phosphetising

Two coats of primer

Two coats of enamel paint in specified shade (Dove Gray)

(Epoxy Based or other types of painting will be provided when specified.)

Name-plates

 

Each panel will have it's main name plate as per drawing. Each push button station will have a label indicating capacitor bank no, which it controls.

The earthing points will have earthing stickers.

Inside the panel, each contactor station will have a capacitor bank no. Label indicating the bank it controls.

The Labels will be in aluminium plate suitably etched and painted. (Any other type of label or any extra labels will be provided when specified).

 

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