These instructions apply to Isolation Switch model SW-50 that is to be installed on an in-service Dairyland model PCR or SSD decoupler that is not installed in a Dairyland pedestal.
WARNING:
When Isolation Switches are used in ac voltage mitigation applications, if multiple or all decouplers are disconnected, the pipeline voltage may rise to an unsafe level (i.e., above the
15Vac that NACE standards consider safe). Therefore, safety precautions should be implemented by the user when decouplers are isolated from the pipeline, particularly at pipeline contact points. Dairyland will provide suggested procedures for installing and operating the Isolation Switch, but the user must be responsible for and approve the procedures to be used by its workers when initially installing the Isolation Switch in a field retrofit installation and when operating the Isolation Switch to disconnect or reconnect a decoupler because Dairyland cannot be familiar with each users safety guidelines.
WARNING:
Isolation Switches are not to be installed in a defined hazardous location, but rather in an “ordinary” location.
CAUTION:
When a PCR or SSD is being used to provide ac grounding for an item of electrical equipment, an Isolation Switch should not be installed because per electric codes such equipment must always be solidly AC grounded.
This isolation switch is for use with a Dairyland PCR or SSD model decoupler that is not installed in a Dairyland pedestal. This Isolation
Switch is not to be used with a PCR model that has an 80A steady state AC current rating unless the ac current flowing through the decoupler is first verified to be less than 50A. This switch is only to be installed in above ground locations where it will not be submerged.
Isolation Switch: SW-50
For worker safety during installation, it was recommended in
Dairyland’s Isolation Switch ordering information that the user obtain certain equipment; namely a pair of electrically insulated gloves, a shorting cable with approximate 3 ft length with insulated clamps on each end, a multi-meter to measure ac voltage, and a clamp-on ac ammeter to measure ac current. (Of these items,
Dairyland offers a suitable 3 ft long 1/0AWG shorting cable with insulated clamps, Model# “BCL-1/0”.) The following installation procedure assumes that these items are available. The use of the shorting jumper is illustrated for certain steps, but its use may not be necessary if the installer has measured and knows that the pipelineto-earth voltage is at an acceptable touch voltage level for each step of the installation procedure, including when the conductor from the pipeline may be momentarily or accidentally disconnected from the grounding conductor. However, it is suggested that the shorting jumper always be used as a safety precaution in the unlikely event of an electrical disturbance while the Isolation Switch is being installed.
If the voltage one is working with is not known to be at a safe touch potential, then insulating gloves should be used.
Model: BCL-1/0
Dairyland Electrical Industries • P.O. Box 187 Stoughton, WI 53589 • 608-877-9900 • www.dairyland.com • marketing@dairyland.com
Rev. 4/14

Recommended installation tools include: (a) 3/8 drive ratchet wrench with a ¾”, 9/16”, and ½”, sockets (with an extender for the 1/2” socket), and (b) a ¾”, 9/16”, and ½”inch box end or gear wrench. These tools accommodate connecting the Isolation Switch to either a PCR or
SSD decoupler.
potential when it is removed from the decoupler terminal if it is not grounded. The photo shows the jumper clamps connected to a PCR but the procedure is the same for an SSD as shown in the photo on the right but without clamps attached.
Switch Installation Procedure
(Applies to either a PCR or SSD decoupler)
1. Mount the Isolation Switch to an appropriate support (user furnished) using the C-channel bracket furnished with the Switch or remove this bracket and use the holes in the enclosure flange.
Mounting bolts are to be user provided.
2. A new insulated lead will be required to make a connection between the copper bus terminal on the right side of the Isolation Switch and the decoupler negative terminal. This lead must have connectors on each end compatible with the terminal pads this lead will to be connected to (i.e. appropriate connector hole size which will be different for a PCR versus an SSD). Upon request, Dairyland can furnish leads with connectors on each end for connecting this switch to an SSD or
PCR if the lead length required is provided and Dairyland is advised of the decoupler type this Switch will be connected to. A #2AWG lead would be provided for connecting to an SSD and a 2/0 AWG for connecting to a PCR. This lead must be available before proceeding.
5. Taking care not to dislodge the cable clamps, remove the nut, bolt, and washers securing the lead attached to the negative decoupler terminal.
3. It is important to know the voltage and current associated with the leads to be handled during the installation process. It is recommended that the installer first measure the ac current flowing through the decoupler with a clamp-on ammeter and measure the ac voltage from the negative decoupler terminal to a metal probe (e.g., a long shank screwdriver) pushed into the earth where the worker will be standing to install the switch as this will represent the worker touch potential.
If NACE guidelines were followed, the voltage measured should, but may not, be less than the 15Vac that NACE considers safe, which is the reason for recommending this measurement.
4. Regardless of the voltage measured in Step 3, connect the black jumper clamp to the positive terminal of the decoupler and connect the red clamp to the connector body (not the decoupler terminal pad) on one of the conductors attached to the negative decoupler terminal (In most cases there will be only one conductor.) The reason is that the voltage on this conductor may increase to an unsafe touch
6. To determine if the remaining steps can be conducted without the use of insulated gloves, while holding the insulated lead, connect a multi-meter, set to measure ac volts, between the connector of the lead just removed and a metal probe (e.g. screwdriver) pushed into the earth. Then while holding the insulated part of the lead, momentarily remove the clamp from the connector on this lead to measure the voltage to earth (i.e., the touch potential). If this potential is not considered a safe touch potential by your company work practices, then reconnect the jumper clamp so this lead remains grounded throughout the entire installation process and as an added safety precaution consider using insulated gloves for the remaining steps.
If the measured touch potential is considered safe by your company when ungrounded, it is still recommended that the jumper clamp be reconnected for all remaining steps as a safety precaution. With the shorting jumper reattached to the lead just removed, set it aside and proceed to the next step.
Dairyland Electrical Industries • P.O. Box 187 Stoughton, WI 53589 • 608-877-9900 • www.dairyland.com • marketing@dairyland.com

Dairyland Electrical Industries • P.O. Box 187 Stoughton, WI 53589 • 608-877-9900 • www.dairyland.com • marketing@dairyland.com
9. Last, completely insulate the left bus of the Isolation Switch and the connector on the lead connected to this bus. The reason is that if this decoupler is one of many used to mitigate ac voltage on a pipeline, when all decouplers are isolated from the pipeline, the voltage on this lead could rise to an unsafe touch potential when the Isolation Switch is disconnected. The insulating material for the terminal is to be user furnished. Also consider insulating the other Isolation Switch terminal and decoupler terminals. Below are completed installations for Switch connection to a PCR and SSD except without the negative decoupler terminals insulated.
7. Reconnect the lead from the negative decoupler terminal to the bus terminal on the left side of the Isolation Switch using the bolt, washers, and nut sets already provided with the Switch. Use a 3/8” dia bolt with two flat washers (one under the bolt head), split lock washer, and nut if the lead was connected to a PCR and use a 5/16” dia bolt with two flat washers (one under the bolt head), split lock washer, and nut if the lead was connected to an SSD. Tighten the nuts securely.
Completed Isolation Switch Installation
10. Last, before closing and locking the Isolation Switch enclosure: a. If the decoupler is to be left disconnected from the cathodically protected structure, confirm that the toggle switch is OPEN in the
UP position and that movable the link is OPEN.
b. If the decoupler is to be left connected to the cathodically protected structure, confirm that the toggle switch is OPEN in the UP position and the link closed with both link bolts torqued 10–12 ftlbs (13.5–16 Nm). Do not over torque.
8. Connect one end of the new lead described in Step 2 to the negative decoupler terminal using the hardware that was previously in this decoupler terminal. Left photo below. Connect the other end of this lead to the terminal on the right side of the Isolation Switch using the 5/16” or 3/8” bolt, washers, and nuts as described in step 7 and tighten the nut securely. Right photo below.
Isolation Switch Operation
1. Procedure for Disconnecting a Decoupler
Caution:
When all decouplers on a pipeline that has an AC mitigation system have been disconnected, the pipeline voltage, which also exists on the bare metal switch parts, may be above a safe and acceptable touch potential. Therefore, as a precaution, use electrically insulated gloves or an insulated wrench whenever operating the Isolation Switch. When all decouplers have been reconnected, the pipeline voltage should return to its fully mitigated level.
Caution:
If the Isolation Switch was installed to a PCR model that has an
80A steady state AC current rating, do not use the Switch unless the AC current flowing through the decoupler is first verified to be less than the switch rating of 50A.
Dairyland Electrical Industries • P.O. Box 187 Stoughton, WI 53589 • 608-877-9900 • www.dairyland.com • marketing@dairyland.com

Whenever the decoupler is connected to the pipeline (or other cathodically protected structure) the toggle switch should be UP in its
OPEN position and the link UP in its CLOSED position with both link bolts torqued 10–12 ft-lbs (13.5-16 Nm). Do not over-tighten.
c) Last, move the toggle switch UP to its OPEN position. The decoupler is now disconnected (isolated) from the system to which it was connected. Any arcing will be contained within the enclosed toggle switch.
a) To disconnect the decoupler, first move the toggle switch DOWN to its CLOSED position. This provides an alternate connection between the decoupler and the cathodically protected structure.
The toggle switch is now in parallel with the moveable link.
2. Procedure for Reconnecting a Decoupler a) To reconnect the decoupler, first move the toggle switch DOWN to its CLOSED position as illustrated in Step 1.a. Using a ½” ratchet with an extension, move the link to its closed position. Torque both link bolts 10–12 ft-lbs (13.5-16 Nm). Do not over-tighten.
b) Using a ½” ratchet wrench with an extension, loosen, but do not remove, the 5/16” hex bolts on each end of the movable link. Use the wrench to pivot the link against the link stop as illustrated in the following photo. No arcing will occur because the current has a parallel current path through the closed toggle switch.
b) Last, move the toggle switch UP to its OPEN position. The decoupler is now reconnected to the cathodically protected structure.
Always leave the toggle switch UP in its OPEN position when the decoupler is connected, as only the moveable link is rated for AC fault or lightning current. Close and lock the enclosure after verifying that the toggle switch and link are in the correct positions.
Dairyland Electrical Industries • P.O. Box 187 Stoughton, WI 53589 • 608-877-9900 • www.dairyland.com • marketing@dairyland.com