Insulated Joint Protection

Problem:
When an insulated joint is used to electrically isolate sections of pipeline, over-voltage protection of the joint insulation may be necessary. The insulation can fail, due to lightning or AC fault current, with potentially disastrous results. Arcing across the joint will cause insulation failure and possible ignition of flammable gases.

Solution:
A protection device connected across the insulated joint will limit the voltage to safe levels, and provide a conduction path around the joint, while maintaining cathodic protection. Products listed for use in hazardous locations will address the over-voltage problem while assuring safe operation.

To implement an insulated joint protection system, the following issues need to be examined to determine product selection and ratings:
1. The maximum DC voltage present across the insulated joint
2. Whether induced AC voltage is present at the site
3. Examine AC fault current exposure
4. Location of the device, and the resulting conductor length
5. Is this site classified as a hazardous location
6. For mounting options, see data on each product page

See Application Note 1 for a full review of this application.