Weathermatic SLGDT Lightning Arrestor
Weathermatic SLGDT gas discharge tube lightning arrestors must be
used on all 2-wire grids. The SLGDT lightning arrestor attaches directly
to the 2-wire system and helps dissipate static electricity generated by a
nearby lightning strike. While Weathermatic components have lightning
arresting features, the SLGDT provides an extra measure of protection.
- Protects the 2-wire system from excessive static charges created by a lightning strike.
- Sealed and impervious to moisture, salts, fertilizers and mild chemicals. Can be buried directly in the soil.
- Shock resistant
- Freeze/heat resistant (-20° to 60° C)
- No electrical contact with the soil
- Each Lightning Arrestor protects a 300 foot radius
- Requires no power from the 2-wire system
- Can only be connected to SmartWire™ 2-wire systems
Procedures for Installation
- Connect the RED and BLACK lead wires to the 2-wire system RED and BLACK wires.
- Attach the GREEN ground wire to Earth Ground.
- Use only DBY or DBR 3M Type waterproof connectors encapsulating a twisted wire connection inside a metal block (SLCONN included).
- For maximum protection, place an SLGDT every 600 feet along the 2-wire system.
- One SLGDT should be within 25 ft of the host SmartLine® controller.
- A single stub line must not exceed 50 feet without an SLGDT lightning arrestor.
- An SLGDT lightning arrestor must also be placed at the end of the 2-wire run that is the maximum distance from the SmartLine® controller, or if looped, at the point of maximum distance from the SmartLine® controller.
- The GREEN ground wire must be attached to a #8 solid bare copper wire using the included SLCONN wire connector. Connect the bare ground wire to a grounding circuit with 12 Ohms or less resistance to earth ground, measured with a ground resistance meter or Megger.
- A grounding circuit is comprised of 4 major components:
- Ground Rod(s) and/or Plate(s).
- Ground Conductor.
- Exothermic or Cadmium Weld connections.
- Soil and/or Ground Enhancement Materials.
- Ground Rods/Plates must be installed in a 6” min. valve box, 6” below grade or below frost line, located within an irrigated zone to maintain soil moisture and maximum ground performance.
- 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.
- 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.l®
- Ground Enhancer Materials such as Powerset®, PowerFill®, and GEM® shall be used as required 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, 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.
- Refer to www.erico.com for a complete line or grounding equipment and materials.
- Refer to www.asic.org/design_guides.htm for American Society of Irrigation Consultants (ASIC) Guideline 100-2002 for Earth Grounding Electronic Equipment in Irrigation Systems.