# California Public Utilities Commission — Pipeline Safety Interpretation

- **operation:** document
- **citation:** PI-93-053
- **title:** California Public Utilities Commission — Pipeline Safety Interpretation
- **source type:** guidance
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** guidance
- **official:** true
- **published on:** 1993-08-19
- **effective on:** Not available
- **summary:** PI-93-053 response to California Public Utilities Commission concerning 192.467.
- **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-93-053.json
- **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-93-053.md
- **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-93-053
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1993/PI93053.pdf
**body:**

<<<PAGE 1>>>

August 19, 1993
Mr. Russell W. Copeland
Chief, Utilities Safety Branch
California Public Utilities Commission
505 Van Ness Avenue
San Francisco, CA 94102-3298
Dear Mr. Copeland:
This responds to your letter of July 16, 1993, concerning the corrosion control
requirements in 49 CFR Part 192. Answers to your questions are stated below.
1. Section 192.467(a) requires each pipeline on which external corrosion control is
required to be electrically isolated from other underground metallic structures,
unless the pipeline and the other structures are electrically interconnected and
cathodically protected as a single unit. Under this requirement, the electrical
interconnection must be designed and installed as apart of the cathodic protection
system to enable the pipeline and other structures to be cathodically protected
together. Subsequent "pipe-to-soil" readings on the other structures indicating
adequate protection would also indicate the electrical interconnection is
functioning as designed.
2. Section 192.467(b) requires one or more insulating devices to be installed where
electrical isolation of a portion of a pipeline is necessary to facilitate the application
of corrosion control. Under this section, insulating devices are required only when
the portion of pipeline being protected is electrically isolated to achieve the
required level of cathodic protection. If the required protection is achieved
without isolation, no insulating devices are required.
3. We agree that if a pipeline is not required to have cathodic protection, §192.467(b)
does not require the pipeline to have insulating devices.
Sincerely,
Cesar De Leon
Director, Regulatory Programs
Office of Pipeline Safety
dal\192.467\93-08-19
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