Weathermatic SLFSI-T10 Design Manual page 9

Ground Rods/Plates must be installed 6" below grade or below frost line, located within an irrigated
zone to maintain soil moisture and maximum ground performance. All connections must be made in a
minimum 6" min. valve box. Rods are installed perpendicular to the ground while plates are installed
horizontal to the ground. See manufacturers recommendation for correct installation.
Ground Rods shall be UL listed "copper clad", 5/8" minimum diameter, 8' of length, and must meet the
requirements of NEC article 250-52(c).
Ground Plates shall be a copper alloy specifically intended for grounding, with a minimum thickness of
0.060". Each plate shall expose a minimum of 5 square feet of surface area to contact the soil, and meet
the requirements of NEC article 250-52(d).
Grounding Conductor shall be a solid, bare copper wire or strap used to connect the green ground wire
to the ground rod or plate, sized appropriately to achieve specified resistance.
NOTE: The bare copper wire should run perpendicular to the two-wire path
Exothermic or Cadmium Weld products such as CADWELD One Shot ®, shall be used to connect the #8
AWG bare copper ground conductor to the ground rod or plate.
Ground Enhancement Materials such as Powerset®, PowerFill®, and GEM® shall be used as required to
achieve specified resistance to earth ground.
Local soil and site conditions will dictate what extent of grounding measures will be required. Generally
there are 3 soil types that each require different methods and equipment to achieve the 12 Ohm
minimum resistance to ground:
•
Clay soils: A single ground rod is typically sufficient, located in an irrigated zone, with CADWELD
connections and no soil amendments. Some sites require a 6" diameter hole to be augured and
backfilled with Ground Enhancement Materials.
•
Loam Soils: Typically a 3-ground rod grid is required, located in an irrigated zone, with CADWELD
connections, 6" augured holes and Ground Enhancement Material as required.
•
Sandy soils: Require the most extensive ground circuits which require combinations of ground rods,
plates, CADWELD connections and ground enhancement materials, located in an irrigated zone.
Any combination of the above recommendations should be considered to achieve 12 Ohms or less.
Long-term maintenance of any ground system requires that it be located within an irrigated or wetted
zone.
NOTE - DO NOT USE single screw ground clamps as these clamps will loosen
over time.
Weathermatic recommends the use Exothermic or Cadmium Weld connections for all
ground rod and plate connections. See
is done.
9 | P a g e
https://youtu.be/T5DoB26TFtI
Single screw
ground clamp
for video of how this
Cadweld One Shot