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ERICO GEM 25A
GEM 25A

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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ERICO’s GEM 25A Ground Enhancing Material is a superior conductive material that improves grounding effectiveness, especially in areas of poor conductivity such as rocky ground, areas of moisture variation, and sandy soils.

Features:
• Effective-typical resistivity 12-18 Ohm cms (20 times lower than bentonite clay)
• 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
• Easily installed in dry form or slurry
• Meets (USA) Environmental Protection Authority requirements for landfill
• Can be installed using Trench or Ground Rod Backfill methods

Applications:

• 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 ERICO's GEM Software Calculator. The calculator estimates the amount of GEM required for an installation and converts Metric and Imperial measurement units.

GEM Information
GEM info PDF Erico Testimonial Test Site Comparison Enhanced Grounding Paper

How to Specify:
• Ground enhancement material in its set form shall have a resistivity of not more than 20 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

Ground Enhancing Material (GEM) Installation Methods

Trench Installation

Estimated linear feet of ground conductor covering with each bag of GEM

Trench Width

Total 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’)

30cm (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).

Method

1. Dig a trench at least 10.2 cm (4 inches) wide x 76.2 cm (30 inches) deep or below the frost line, whichever is deeper. Spread out enough GEM to uniformly cover bottom of trench - about 2.5cm (1 inch) deep.
2. Place copper tape / earth grid conductor on top of GEM.
3. Spread another 3 cm (1 inch) deep layer of GEM around and on top of the conductor so as to completely cover conductor.
4. Carefully cover the GEM with soil to a depth of about 10 cm (4 inches), making sure not to expose the conductor. Tamp down the soil, then fill in the trench.

Please note that this is a guide to installation only. Full instructions will be supplied at time of product purchase.

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 hole

Depth 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")

2

2

2

2

4

4

4

10.0cm (4")

2

3

3

3

6

7

7

12.5cm (5")

3

4

4

5

9

10

10

15.0cm (6")

5

5

6

7

13

14

15

17.5cm (7")

6

7

8

9

17

19

20

20.0cm (8")

8

9

11

12

22

25

26

22.5cm (9")

10

12

13

15

28

31

32

25.0cm (10")

12

14

16

18

34

38

40


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

Method

1. Auger a 7.6cm (3 inch) or large diameter hole to a depth of 15.0cm (6 inches) less than the length of the ground rod.
2. Place ground rod into augured hole and drive it using the steel head and hammer approx 30 cms (one foot) into bottom of the hole. The top of the ground rod will be approximately 15.2cm (6 inches) below the level of the grade. At this time, make any connections to ground rod using CADWELD® connections.
3. Pour the appropriate amount of GEM (see below) around the ground rod. To ensure the GEM material completely fills the hole, tamp around the ground rod with a pole.
4. Fill remainder of augured hole with soil removed during auguring. For various augured-hole diameters and depths, see the table above.

Note: Excess standing water must be removed the hole.

Note: When premixing GEM in a slurry form, use a standard cement mixer or hard-mix in a mixing box, wheelbarrow, etc.
Use 5.5 to 7.5 litres (1.5 to 2 gallons) of clean water per bag of GEM.

Please note that this is a guide to installation only. Full instructions will be supplied at time of product purchase.

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