switches, socket outlets and other instruments shall be concealed in walls.

The installation instructions for surface and concealed conduits given in this section are also applicable to the installation of steel conduits and accessories.

32.5.4 Galvanized Iron Pipes
The galvanized iron (G.I) pipes shall be installed at a minimum depth of 900 mm measured from the top of pipes to finished ground level. The pipe shall be laid and checked for soundness before completion of civil works. The G.I. pipes at the entrance of the buildings shall be installed at locations as shown on the drawings.

At all joints the pipes shall be firmly screwed and cotton yarn with water-proof compound shall be used to make the joint water-proof.

At each termination, the pipe end shall have threads and socket screwed on thread for installing soft metal bush. The soft metal bush shall be of approved quality and shall be male type.

The installation of pipes shall be complete in all respects including its fixing at terminations before the work is started. All sharp edges and burrs shall be removed by using reamer or any approved device.

The pipe shall be checked before installation of cable for any obstruction. If found, it shall be cleared without damaging the installation. All pipe ends shall be plugged to prevent entry of water, rodents etc.

32.5.5 PVC Pipe & Accessories
Rigid PVC pipes shall be installed under roads, paved areas, at crossing with other services and at cable entering building as shown on the drawings. The depth of the pipe shall very according to the conditions at site, and approval of Engineer shall be obtained prior to installation. In general the pipes shall be installed underground at the following depths measured from the top of the pipe:
- Under roads/pavement : 900 mm below finished surface
- When crossing outer : 250/500 mm vertical/horizontal
services clearances with concrete cover.

The trench of required dimensions shall be excavated and the bottom of trench cleaned and leveled. A 75 mm bed of fine sand shall be provided over which the PVC pipes installed after proper alignment. Where two or more pipes are installed in the same trench the clearance between pipes shall not less than 50 mm. After laying of pipe the trench shall be backfilled with clean screened earth in layers of 75 mm, each layer properly tamped and compacted.

Where underground cables enter connection terminal boxes the PVC pipe shall be installed on surface by means of galvanized steel clamps at a maximum internal of 450 mm.

After installation, the ends of the pipe shall be plugged with material impervious to water and chemicals. All joints shall be sealed adequately to prevent entry of foreign elements.

The installation of pipes shall be completed in all respects including its fixing at terminations, before cabling work is stated. All sharp edges and burrs shall be removed by using reamer or any approved device. The pipe shall be through cleaned of dirt and dust from inside, the pipes shall be installed in proper coordination with other works.

32.6 Measurement and Payment 32.6.1 Measurement
Items covered under this section of technical specification will be measured in units specified in BOQ for the work satisfactorily completed as shown on the Drawing or as directed by the Engineer.

32.6.2 Payment
Payment will be made in accordance with the unit prices in the BOQ of various items in accordance with the specifications and shall constitute full compensation for furnishing all materials, equipment and labour and for performing all operations necessary to complete the work.