Copper Bonded Steel Electrode shall be made of high tensile low carbon steel circular rods, molecularly bonded with copper on outer surface to meet the requirements of Underwriters Laboratories (UL) 467-2007 or latest. Such copper bonded steel cored rod is preferred due to its overall combination of strength, corrosion resistance, low resistance path to earth and cost effectiveness.
The earth electrode shall be UL listed and of minimum 17.0mm diameter and minimum 3.0mtrs. long.
The minimum copper bonding thickness shall be of 250 microns.
Marking: UL marking, Manufacturer’s name or trade name, length, diameter, catalogue number must be punched on every earth electrode.
Earth electrode can be visually inspected, checked for dimensions and thickness of copper coating using micron gauge. The suppliler shall arrange for such inspection at the time of supply, if so desired..
RDSO/PE/SPEC/PS/0109-2008 having diameter not less than 17 mm complying with requirements of BS 4360 Grade 43A or EN10025:2-004 S275JR, molecularly bonded by 99.99% pure high conductivity copper on outer surface with copper coating thickness 250 micron or more, Length 3000 mm (minimum). Length of the electrode may be increased in multiple of 1 meter to reduce earth resistance if required. To increase the length, pieces of similar rod shall be either exothermally welded to basic 3 meter electrode or connected using socket of suitable size. These sockets shall also be molecularly bonded by 99.99% pure high conductivity copper on inner & outer surface with copper coating thickness 250 micron or more. Copper bus bar of size 250 mm x 50 mm x 6 mm having electrical conductivity of 101% IACS, minimum 99.9% copper content shall be exothermically welded to rod with 4 holes of 12 mm dia. (2 on each side) for connecting earthing conductor. Current carrying capacity: The design of the electrode should be such as to have more than 15kA current carrying capacity for 1 second.
Concentric pipe earth electrode:
Primary conductor: MS pipe with 25 - 50 mm diameter, class B, ISI mark as per IS-1239, Length 2000 or 3000 mm
Secondary conductor: MS pipe with 40-100 mm diameter, class B, ISI mark as per IS-1239, Length 2000 or 3000 mm