This paper discusses the effects of coupon size, geometry, distance between the potential sensing area and the coupon, material selection for the coupon, installation of the probes with coupons, and potential measurement interpretation on pipelines and coupons. Test results measured on a probe with a flat coupon and narrow sensing strips and a comparison of coupon potentials after potential decay and corrosion
potentials is also presented. Keywords: coupons, cathodic protection probes, protection criteria, soil voltage drop, “on” potentials, “off’ potential, potential decay.