A Technical Note: Temporary Ground Beds by the Roll^* Available to Purchase

Household aluminum foil, spread out on moistened ground, or preferably in water or a damp ditch can be used satisfactorily as a temporary ground bed for making calculations of the current required to protect an underground installation. A 25-foot strip of aluminum will hold output constant for several hours, but for tests of 8 hours at 15 amperes or more, two 25-foot strips are recommended. Resistances as low as one-half ohm have been obtained and current output can be regulated by folding the foil back on itself.