Model UC1 does not have an AC coupon.
Style A is installed at the base of a test station riser as shown in drawing UC-9. A zinc reference electrode can be installed in the housing as an option.
The Model UC Underground Cathodic Protection Coupon is fitted to the base of a test station riser. It is designed to allow essentially IR-Drop free measurements with CP current on. The amount of IR-Drop error included in a current-on measurement is negligible and can therefore be ignored in routine measurements. Refer to NACE paper 05039, available on our web site, for quantitative performance data. Many factors contribute to the magnitude of IR-Drop error at any particular site; therefore it is recommended that each installation be calibrated separately.
Style A - Test Station Foot Use Style A when the coupon is affixed to the base of a test station. This style may be ordered with or without the optional zinc reference.
All coupons are internally connected to a 4-conductor 18 ga. cable. The red and black wires are connected to the DC coupon, the blue wire is connected to the optional zinc reference electrode, the orange wire is not connected on Model UC1.
Specify as EDI Model UC1z-xxx-LWnnn where
z = A for Style A test station foot
z = B for Style B self contained
xxx = BDG for no internal reference electrode (only on Style A)
xxx = ZIN for an internal packaged zinc reference electrode nnn = lead wire length in feet.
Note: If no lead wire length is specified, 10 feet (3 meters) will be supplied (LW010).
Wiring - Connect a structure wire and one of the DC coupon wires to a terminal pair that can be shunted through a switch or shorting bar. For convenience, a magnetic switch such as EDI Model UI-MS may be used. Connect the other DC coupon wire, the second structure wire, the AC coupon wire and the reference wire each to their own terminals.
Calibrating - Measure the potential when the switch is closed and the instantdisconnect potential as the switch is opened. The difference between the two is the offset potential which should be recorded. This offset potential will usually be less than 10 millivolts.
Measurements - Measurements can be made with the switch or shorting bar closed. In most cases, the offset potential will be sufficiently small that it can be neglected.
The Model UC Underground Cathodic Protection Coupon is designed to minimize IR-Drop error in measurements made with CP current on. With this unit the amount of IR-Drop error included in a current-on measurement is negligible and, therefore, can be ignored in routine measurements. Since many factors contribute to the magnitude of IR-Drop error at any particular site, it is recommended that each installation site be calibrated separately.