ERICO GEM User Manual

INSTRUCTION SHEET

GROUND ENHANCEMENT MATERIAL (GEM)

GEM Resistivity ≤ 2 Ohm-cm; 2-Electrode Method.

Complies to IEC 62561-7.

TRENCH INSTALLATION

1. Premix GEM into a slurry form. Use 1.5 to 2 gallons (5.7 to 7.6 liters)
of clean potable water per pail of GEM.

2. To mix GEM into a slurry form, use a standard cement mixer or
mix in the GEM pail, a mixing box, wheelbarrow, etc. Use 1.5 to 2
gallons (5.7 to 7.6 liters) of clean-potable water per pail of GEM.
Do not mix GEM with salt water.

3. Spread out enough GEM to uniformly cover bottom of
trench – about 1 inch (2.5 cm) deep. (See table)

4. Place conductor on top of GEM. (See Note 1)

5. Spread more GEM on top of conductor to completely cover
conductor – about 1 inch (2.5 cm) deep. Allow GEM to harden.
Wait 30 minutes to 1 hour before filling the trench with soil backfill.

GEM

6. Carefully cover the GEM with soil to a depth of about 4 inches
(10 cm), making sure not to expose the conductor.

7. Tamp down the soil, then fill in the trench.

Note 1: Wait for the GEM to harden, about 15 to 20 minutes, before

placing the conductor on top of the GEM. You must apply
4 inches (10 cm) of insulating material to the conductors and
ground rods exiting the GEM, starting 2 inches (5 cm) inside

GEM

the GEM.

Note 2: Excess standing water must be removed from trench.

Estimated linear feet of ground conductor covering with each pail of GEM.

Total Thickness of GEM (inches / cm)

Trench Width

(inches / cm)

1” 2.5 cm 2” 5.0 cm 3” 7.5 cm 4” 10.0 cm

4” 10.0 cm 14.0’ 4.27 m 7. 0 ’ 2.13 m 4.7’ 1.43 m 3.5’ 1.06 m
6” 15.2 cm 9.3’ 2.83 m 4.7’ 1.43 m 3.1’ 0.94 m 2.3’ 0.70 m
8” 20.3 cm 7.0 ’ 2.13 m 3.5’ 1.06 m 2.3’ 0.70 m 1.8’ 0.55 m

10” 25.4 cm 5.6’ 1.70 m 2.8’ 0.85 m 1.9’ 0.57 m 1. 4’ 0.42 m
12” 30.5 cm 4.7’ 1.43 m 2.3’ 0.70 m 1.6’ 0.48 m 1.2’ 0.37 m

A 25-pound pail of GEM will cover 7 linear feet (2.1 m) of conductor length for a 4-inch-wide (10 cm), 2-inch-thick
(5 cm) covering (1 inch (2.5 cm) below and 1 inch (2.5 cm) above conductor), based on a density of 63.5 lb/cu.ft.

4”

10 cm

Trench

Ground Conductor

30”

1”

75 cm

2.5 cm

GEM

Soil

Soil Backfill

1”

4”

10 cm

2.5 cm

WARNING

1. ERICO products shall be installed and used only as indicated
in ERICO product instruction sheets and training materials.
Instruction sheets are available at www.erico.com and from
your ERICO customer service representative.

2. ERICO products must never be used for a purpose other than
the purpose for which they were designed or in a manner that
exceeds specified load ratings.

3. All instructions must be completely followed to ensure proper
and safe installation and performance.

4. Improper installation, misuse, misapplication or other failure to
completely follow ERICO’s instructions and warnings may cause
product malfunction, property damage, serious bodily injury
and death.

SAFETY INSTRUCTIONS: All governing codes and regulations
and those required by the job site must be observed. Always use
appropriate safety equipment such as eye protection, hard hat,
and gloves as appropriate to the application.

Ground Enhancement Material (GEM) contains hydraulic cements
and should be handled with the same precautions as used with
portland cement.

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

Copyright ©2005, 2010, 2012 ERICO International Corporation. All rights reserved.
CADDY, CADWELD, CRITEC, ERICO, ERIFLEX, ERITECH, and LENTON are registered trademarks of ERICO International Corporation.

PLEASE OBSERVE THESE SAFETY PRECAUTIONS
KEEP OUT OF REACH OF CHILDREN

CAUTION

Contact with GEM is irritating to respiratory system and skin.
Avoid contact, ingestion or breathing the product.

1. Risk of serious damage to eyes. Wear eye protection.
If GEM gets into the eye, rinse immediately and repeatedly
with water and seek prompt medical attention.

2. Do not breathe dust. Wear respiratory protection when

exposed to GEM dust.

3. Protect skin with boots, gloves, clothing and eye/face protection.

4. Avoid prolonged contact of GEM with skin. Wash skin promptly

after any contact with GEM.

5. If GEM is ingested, drink large quantities of water immediately

and then induce vomiting. Get medical attention immediately.

6. Do not smoke when using GEM.

7. Do not expose GEM to open flame.

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INSTRUCTION SHEET

GROUND ROD BACKFILL INSTALLATION

diameter

augered hole

6”

15 cm

6” shorter than

Ground Rod

15 cm

Ground Rod

12”

30 cm

6”

15 cm

Soil Backfill

GEM packed

around

Ground Rod

1. Auger a 3-inch (7.5 cm) or larger diameter hole to
a depth of 6 inches (15 cm) shorter than the length
of the ground rod.

2. Place ground rod into augered
one foot (if

possible) into bottom of the hole.

hole and drive

The top of the ground rod will be approximately
6 inches (15 cm) below grade. At this time, make
any connections to ground rod using CADWELD

®

connections. (See Note 1)

Premix GEM into a slurry form. Use 1.5 to 2 gallons

3.
(5.7 to 7.6 liters) of clean-potable water per pail of GEM.
The installation of GEM in a dry state is acceptable for
vertical ground rod applications.

4. Pour the appropriate amount of GEM (see table)
around the ground rod. To ensure the GEM material
completely fills the hole, tamp around the ground
rod with a pole. Wait 30 minutes to 1 hour before
filling the hole with soil backfill.

5. Fill remainder of augered hole with soil removed
during augering. For various augered-hole
diameters and depths, see the table below.

Note 1: 4

inches

(10 cm) of insulating material should be

applied to the conductors and ground rods exiting

inches

the GEM, starting 2

(5 cm) inside the GEM.

Note 2: Excess standing water must be removed from

the hole.

Estimated pail of GEM for backfilling around ground rods to a density of 63.5 lb/cu ft

Depth of hole (feet)*

Dia. of hole

(inches / cm)

3 7.5 2 2 2 2 4 4 4

4 10.0 2 3 3 3 6 7 7

5 12.7 3 4 4 5 9 10 10

6 15.2 5 5 6 7 13 14 15

7 17.8 6 7 8 9 17 19 20

8 20.3 8 9 11 12 22 25 26

9 22.9 10 12 13 15 28 31 32

10 25.4 12 14 16 18 34 38 40

* 8-foot (2.4 m) minimum rod length required to be in contact with the soil (or GEM), per NEC® 250-83-C.

Note: To mix GEM into a slurry form, use a standard cement mixer or mix in the GEM pail, a mixing box,

wheelbarrow, etc. Use 1.5 to 2 gallons (5.7 to 7.6 liters) of clean-potable water per pail of GEM.
Do not mix GEM with salt water.

6’ 1.8 m 7’ 2.1 m 8’ 2.4 m 9’ 2.8 m 17’ 5.2 m 19’ 5.8 m 20’ 6.1 m

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TECHNICAL SUPPORT

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