Model UL Long-Life Underground Reference Electrode by EDI

30-Year Design Life with Long-Life Gelled Element.


The Model UL is designed for long-term permanent use to obtain accurate potential measurements on buried structures. It is the best choice for those applications where easy installation is possible, such as an open hole or trench. For those situations where there is limited access, the EDI Model US is recommended. A Cu / CuSO4 element should be used in low chloride soils (<500 ppm), while a Ag / AgCl element is recommended for high chloride soil (>500 ppm) in order to obtain the longest possible life. Further information is available from Farwest.

Typical Applications

  • Underground storage tanks, buried pipelines, structures below concrete flooring.


  • 30-year design life with EDI’s LongLife™ gelled element.
  • Proprietary backfill mix to retain moisture and minimize migration of contaminants from the surrounding soil.
  • 50 ft. of #14 AWG HMW/PE lead wire is standard.

Housing Specifications

  • Size: 8" dia. x 16" long
  • Shipping weight: 25 lbs.

Element Specifications

  • Design life: 30 yrs
  • Shelf life: 1 year minimum
  • Stability: ± 5 mV
  • Current drain: 3 uA for 1 min, 0.01 uA continuous

Element Types

  • AGG: saturated gelled Ag / AgCl
  • CUG: saturated gelled Cu / CuSO4


  • SW: 50' of #14 AWG HMW/PE
  • LWnnn: nnn ft. #14 AWG HMW/PE
  • LWnnn: nnn ft. of custom wire


Model Designation

  • Specify as EDI Model UL-xxx-yy, where xxx = element type and yy = termination type.