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GEM - Ground Enhancement Material

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Ground Enhancement Material (GEM) from ERICO is a superior conductive material that solves your toughest grounding problems. Third-party testing has been completed to verify that GEM conforms to IEC 62561-7. This standard introduces a benchmark for corrosion and electrical performance that has been absent from the industry to date.

GEM is a low-resistance, non-corrosive, carbon concrete that improves grounding effectiveness, especially in areas of poor conductivity. The resistivity of GEM is less than 2 ohm-cm; which is less than 1% the resistivity for bentonite clay.

GEM contains portland cement, which hardens when set, making it permanent, maintenance-free and it will never leach or wash away. GEM improves grounding effectiveness regardless of soil conditions. It is the ideal material to use in areas of poor conductivity, such as rocky ground, mountain tops and sandy soil.


  • Resistivity less than 2 ohm-cm
  • Conforms to IEC 62561-7 Standard
  • Once in its “set” form, maintains constant resistance for the “life” of the ground system
  • Performs in all soil conditions even during dry spells
  • Permanent - does not dissolve, decompose or leach out with time
  • Meets (USA) Environmental Protection Authority requirements for landfill
  • Can be installed using Trench or Ground Rod Backfill methods


GEM is ideal for areas with poor conductivity such as rocky ground, mountain tops, sandy soil and areas of moisture variation.

More Information

GEM Calculator
Download the latest version of the GEM Software Calculator. Available in four languages (English, French, German and Spanish), the calculator estimates the amount of GEM required for an installation and converts Metric and Imperial measurement units.

How to Specify

  • Ground enhancement material in its set form shall have a resistivity of not more than 2 ohm-cm
  • Ground enhancement material must be permanent and maintenance-free (no recharging with salts or chemicals which may be corrosive) and maintain its earth resistance with time
  • It must set up firmly and not dissolve or decompose or otherwise pollute the soil or the local water table
  • The ground enhancement material shall be suitable for installation in a slurry form
  • The ground enhancement material shall not depend on the continuous presence of water to maintain its conductivity
  • Must conform to IEC 62561-7 Standard

Ground Enhancement Material (GEM) Installation Methods

Trench Installation

Estimated linear feet of ground conductor covering with each bag of GEM
Trench WidthTotal Thickness of GEM

2.5cm (1")5.1cm (2")7.6cm (3")10. 2cm (4")
10cm (4")4.3m (14.0’)2.1m (7.0’)1.4m (4.7’)1.1m (3.5’)
15cm (6")2.8m (9.3’)1.4m (4.7’)0.9m (3.1’)0.7m (2.3’)
20cm (8")2.1m (7.0’)1.1m (3.5’)0.7m (2.3’)0.5m (1.8’)
25cm (10")1.7m 5.6’)0.9m (2.8’)0.6m (1.9’)0.4m (1.4’)
30 cm (12")1.4m (4.7’)0.7m (2.3’)0.5m (1.6’)0.4m (1.2’)

A 11.1 kg bag of GEM will cover 2.1m (7 linear feet) of conductor length for a 10.2cm - (4-inch) wide, 5.1cm (2-inch) thick covering 2.5cm (1 inch) below and 2.1cm (1 inch) above the conductor), based on 1017 kg /m3 (63.5 lb/cu ft).

Full installation instructions will be supplied with product when shipped.

Ground Rod Backfill Installation

Estimated bags of GEM for backfilling around ground rods to a density of 1442 kg/m3(90 lb/cu ft)
Diameter of holeDepth of hole (feet) *

1.8m (6’)2.1m (7’)2.4m (8’)2.7m (9’)5.2m (17’)5.8m (19’)6.1m (20’)
7.5cm (3")2222444
10.0cm (4")2333677
12.5cm (5")344591010
15.0cm (6")5567131415
17.5cm (7")6789171920
20.0cm (8")891112222526
22.5cm (9")10121315283132
25.0cm (10")12141618343840

* 2.44m (8 foot) minimum rod length required to be in contact with the soil (or GEM). As per NEC®250-83c.


Full installation instructions will be supplied with product when shipped.

NEC is a registered trademark of, and National Electrical Code (NEC) standard is a copyright of the National Fire Protection Association, Inc.


Due to a policy of continued product development, specifications are subject to change without notice.
CADDY, CADWELD, CRITEC, ERICO, ERIFLEX, ERITECH, and LENTON are registered trademarks of ERICO International Corporation.