When decouplers are installed on a pipeline for AC voltage mitigation and over-voltage protection, there may be occasions where disconnection of the decoupler is required. Safe disconnection cannot always be easily accomplished by hand if notable AC induction is present, therefore Dairyland designed the Isolation Switch to serve this need. Where such isolation is necessary, the Isolation Switch allows safe disconnection without causing exposed arcs, in an AC fault-rated design.
Addresses Issues Such As
- Isolation of high frequency signals from locators and coating defect instrumentation
- Decoupler isolation from close interval survey (CIS) operations
- Decoupler testing
Field Installation
Isolation Switches are suitable for field installation to any Dairyland model PCR* or SSD decoupler with a Dairyland pedestal. SWX-100-ENCL models can be factory assembled and delivered ready for installation if all required components are purchased.
SWX-100 Isolation Switches
Pull style switches designed to mount externally to a Dairyland pedestal or in a standalone enclosure.
Safety Considerations
After the Isolation Switch has been installed, disconnection of a decoupler when performing an AC mitigation function will cause the voltage on the pipeline to rise. NACE recommends that exposed pipelines be limited to 15V for personnel safety. Therefore, appropriate user-approved and industry safety precautions should be taken whenever one or more decouplers are disconnected on a pipeline subject to AC influence.
Note that the Isolation Switch is not certified for, and may not be used in, hazardous (classified) locations.
