Corrosion coupons are used to monitor protective effects of the cathodic protection system. Cathodic protection adequacy can be obtained by using coupons of the same metal as that of the protective structure.
Assistant coupons shall be connected to protected structure from one side and another separated test lead shall be used for potential reading to provide absolute IR free measurement. This also requires installation of coupons where they can receive that same exposure to cathodic protection current as does the structure. Installation of a permanent reference electrode in adjacent of coupon will maintain real polarization potential of the defined test surface to be monitor between reference electrode and coupon test lead which the result will be used on further assessment of the effectiveness of Cathodic Protection system.