M.C.Miller Solid State Decoupler

The Solid State Decoupler device is a solid state DC isolation / AC Grounding device designed for specific protection applications generally found in buried pipeline and storage tank systems. The equipment is suitable to be employed in AC Mitigation applications, Over Voltage protection of Insulating Joints, DC isolation and AC Grounding of Cathodically Protected structures.

The Solid State Decoupling devices are fully serviceable. All components are fully accessible and are fully serviceable by suitably skilled technicians. Accessibility enables user programmable blocking/switching voltages.

The Solid State Decoupler functions as a DC voltage level clamping device and can at the same time mitigate AC voltage. This feature allows up to 15A AC induced current to pass and prevents the flow of DC current whilst the DC voltage remains below the pre-determined design blocking threshold. When the DC voltage exceeds the aforementioned threshold the device instantaneously switches on and thereby limits the DC voltage of the device under protection. Immediately the voltage falls as the surge event passes and decays to below the threshold level, the SSD switches off and reverts to its blocking mode.

Our Solid State De-Coupling devices are purpose designed to:

  • De-couple dissimilar metals that must, by regulation or galvanic corrosion, be AC bonded but isolated in the DC mode
  • Isolate electrical DC equipment in Cathodic Protection systems
  • AC coupling to earth where DC blocking/isolation is required
  • Over voltage conditions emanating from Induced AC surges, lightning and switching transients and Rectifier failure
  • Protection of Insulating joints on pipelines
  • Mitigation of AC induced voltages
  • De-Coupling in gradient control (earth / grounding) mats from pipelines and structures

Protection of Insulating joints require overvoltage protection due to the relatively small clearance between the flange faces, bolt to bolt hole and bolt head / nut to flange face. In order to protect the insulating materials used in the insulating flange kit, overvoltage protection devices are applied to ensure the voltage does not exceed pre-determined levels.

Benefits and Features of M.C.Miller's Solid State Decouplers


  • Higher blocking voltages over older technologies such as polarization cells
  • More technically advanced than our competitors
  • Can handle large steady state clamping currents for longer periods of time than Metal Oxide Varistor (MOV)
  • Light weight compact designs


SSD-DCD is used for DC isolation between a pipe and a grounding system. The SSD-DCD clamps the potential to a certain threshold voltage by passing current through to the lower potential between the pipe and the grounding systems. The device then switches itself off if the voltage present reduces back to its desired range.

Features of SSD-DCD

  • Wide DC clamping voltage range
  • High steady state DC current drain of 800A or up to 60A for 15 mins
  • 60Hz AC impedance of 0.04? (Extra)
  • AC steady state current 45A @ 50/60Hz (Extra)
  • Lightning impulse current rating Class 1: 100 kA for 10/350 µs
  • AC fault current rating 3.7kA for 30 cycles
  • Lightning DC spark over voltage - 600V
  • IP68 Submersible design up to two meters in depth

Performance Specifications of M.C.Miller's Solid State Decouplers

Please contact the M. C. Miller sales team for current pricing @ sales@mcmiller.com or 772-794-9448

Or try our new Decoupler Wizard online and submit for information: