how to make LIGHTNING ARESTER ESTIMATE

LIGHTNING ARESTER ESTIMATE

Providing & fixing 25.4 mm. (1") dia 457 mm. (1.5 ft) long solid copper rod with sharp top end for arresting lightning securedly bonded with 6.6 mm. thick 150 mm. x 150 mm. Copper base plate to be recessed in wall complete with nuts, bolts, CC work etc.

Earthing the electrical  installation with 40 mm. (1.5") dia G.I. pipe (Earth electrode)  having 6.35 mm. dia hole across the pipe at 305 mm. interval securedly bonded by soldering with 2 nos.of No2 SWG  HDBC earth leads with its  protection  by 20 mm. (3/4") dia G.I. pipe up-to plinth level run at a depth of 609.6 mm. (2 ft.) below G.L.up-to main board to be earthed including necessary connecting copper sockets, bolts, nuts,  etc. complete for maintaining earth resistance within 1 ohm.

a) Depth of bottom of main electrode at  37338 mm. (122.5 ft) from GL & length of electrode 36576 mm. (120 ft).

Construction of Earthing inspection pit inside measurement 600 mm x 600 mm with 250 mm thick brick in cement morter (1:4) with 100mm thick RCC top slab (1:2:4) with 1% re-inforcement 450 mm dia water sealed CI man-hole cover with locking arrangement including necessary earth works, site filling and one brick flat soling 75 mm thick (1:3:6) base concrete for making inlet channel & 12mm thick (1:2) cement plaster with neat finishing etc.all complete up to a depth of .75 meter.

Providing & drawing No-2 HDBC wire through 12.7 mm. (½") dia G.I. pipe including fitting, fixing the G.I. pipe in wall or column complete as required.