Technical Article

Polarity Matters – Labels On Your Decoupler

Your Dairyland decoupler will come with polarity labels near the terminals for positive (+) and negative (-) connections. Pay close attention to these, as they can be important depending on the blocking threshold held by your specific model. If the device is incorrectly installed with polarities reversed, the unit could go into conduction and short out CP current during normal operating conditions.

PCR Polarity

  • If you purchased a decoupler with a symmetrical DC blocking threshold rating such as -2/+2V, you may connect the terminals in either configuration regardless of polarity.
  • If you purchased a decoupler with an asymmetrical configuration such as a -3/+1 configuration, you will need to connect the negative terminal to the cathodically protected structure and the positive terminal to the grounded side, if one side is grounded.
  • If you have cathodic protection on both sides of anisolation joint, connect the negative terminal to the more electro-negative side. Connect the positive terminal to the side of the flange that is less negative.

For Dairyland PCRX, OVP and ISP devices, the metallic enclosure is electrically bonded to the positive terminalSo, if mounting these devices onto metallic supports, be aware that the support will also be bonded to the positive terminal. When using your decoupler for lightning protection, remember to always connect the decoupler to the flange with the shortest possible lead length.

If you have further questions about installation and proper placement, please contact our technical support team.

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