Structural earthing that stays low-impedance for the life of the building
Foundation rebar bonding, copper bonded and chemical electrodes, exothermic welding, earth bars and enhancement compound — designed from measured soil resistivity to IS 3043:2018 and IEC 62561.
Why the foundation is the most reliable electrode on site
A raft or pile-cap reinforcement cage puts hundreds of square metres of steel in permanent contact with moist soil — an electrode no cluster of 3 m pits can match.
Structural earthing bonds that reinforcement into a certified earth electrode using rebar clamps or exothermic welds, cross-bonded at multiple levels of the cage and brought out to accessible test links above plinth level. IS 3043:2018 and IEC 62305-3 both recognise foundation earthing, and IEC 62561-7 covers the enhancement compounds used alongside it.
The advantages are practical: stable resistance through the dry season, no land consumed by pit clusters on tight urban plots, no risk of an electrode being cut during later landscaping, and a large equipotential reference that limits step and touch potential across the slab.
The constraint is timing. Structural earthing must be built with the structure. DFMHUB works alongside the civil contractor at foundation stage, with photographic and test records taken before every pour — and supplements it with driven, deep-bore or chemical electrodes where the design demands lower values.
Codes and test methods we work to
IS/IEC 62305 (Parts 1-4)
Risk assessment, physical damage protection, and protection of electrical & electronic systems.
IS 3043:2018
Indian code of practice for earthing — electrode sizing, resistance limits and soil resistivity method.
IEC 62561 (Parts 1-7)
Type-testing of LPS components: connections, conductors, electrodes, enhancing compounds and test links.
NBC 2016, Part 8
National Building Code requirements for lightning protection of buildings in India.
IEC 61643 / IS 16571
Selection and coordination of surge protective devices for low-voltage systems.
NFPA 780 & NF C 17-102
International practice for LPS installation and early streamer emission terminals, where specified.
12 ARK Make structural earthing components
Electrodes, bonding hardware, welding systems, chambers and accessories — supplied with test certificates and batch traceability.
ARK Copper Bonded Earth Rods
14/17.2/20 MM, 250 M CUARK Pure Copper Earth Electrodes
SOLID CU, 25-50 MM DIAARK Chemical / Maintenance-Free Electrodes
48/76 MM, 1-3 MARK GI & Copper Earthing Strips
25X3 TO 75X12 MMARK Earth Enhancement Compound
BENTONITE / CONDUCTIVE CEMENTARK Structural Rebar Bonding Clamps
CAST CU ALLOY, 8-32 MM REBARARK Earth Pit Chambers
POLYMER / RCC, A15-D400ARK Earth Bars & Disconnecting Links
CU BAR WITH SS LINKSARK Exothermic Welding System
MOULDS, POWDER, IGNITIONARK Rod Couplers, Driving Heads & Tips
SILICON BRONZE / HARDENED STEELARK Earthing Accessories & Clamps
ROD-TO-TAPE, U-BOLT, A/B TYPEARK Earth Marking Plates & Labels
ENGRAVED SS / BRASSStructural earthing by city
Soil conditions differ sharply between metros — so do our electrode designs.
Structural earthing — frequently asked questions
What is structural earthing?
Structural earthing uses the building's own foundation reinforcement — pile caps, raft slabs, plinth beams and column cages — as an earth electrode, bonded with clamps or exothermic welds and brought out to test links. It is explicitly permitted by IS 3043 and IEC 62305-3 and normally gives a lower, more stable impedance than isolated earth pits.
What earth resistance value is acceptable?
IS 3043 sets values by application: below 1 Ω for large substations and critical facilities, below 5 Ω for most LPS and equipment earths in commercial buildings, and below 2 Ω for data centres and pharma plants. The value must hold in the dry season, not only after monsoon.
Why is soil resistivity testing done before design?
Electrode length, count and type are all driven by resistivity. A Wenner four-pin survey at increasing pin spacings reveals how resistivity changes with depth, showing whether driven rods, deep-bore electrodes or a horizontal grid mat will actually reach conductive strata.
Copper bonded rods or GI pipe electrodes?
GI pipe electrodes corrode and lose contact within a few years in most Indian soils. Copper bonded rods with a 250-micron molecularly bonded coating to IEC 62561-2 hold a 20+ year design life, and solid copper electrodes are used in saline coastal or chemically aggressive ground.
Why exothermic welding instead of bolted clamps?
An exothermic weld is a molecular copper-to-copper joint with the same current capacity as the conductor. It cannot loosen, corrode at the interface, or increase in resistance over time — all common failure modes of buried bolted connections.
Should lightning protection earth and electrical earth be separate?
No. IS/IEC 62305 and IS 3043 both require a single common bonding network. Separate, unbonded earths create dangerous potential differences during a strike. Different functional earths are bonded at the main equipotential bar, directly or through SPDs where isolation is needed.
Can earth resistance be reduced without more electrodes?
Often yes — by using earth enhancement compound such as bentonite or conductive cement around existing electrodes, extending rods deeper with couplers to reach moist strata, or converting to a chemical electrode. Adding rods in parallel only helps if they are spaced at least their own driven length apart.
Send your drawings. Get a compliant system design back.
Share roof plans, structure height and soil data — our team returns a risk assessment summary, air termination or earthing layout, bill of materials and a fixed-price proposal.
- Risk assessment to IS/IEC 62305-2
- IEC 62561 type-tested ARK Make components
- Installation, testing and documented handover