National Electrical Installation Standards

Standards as High as Your Own

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Monday, February 18, 2019

Question:

When you burry. Conduit underground what type of tape do you put on the conduit. You don t put C 130 do you or can you? But what is the tape you apply to the conduit?

David Bastean

A

Answer:

Hey David thanks for your question. The NEC uses the word Approved, as that term is defined in Article 100 for describing various types of corrosion protection in 300.6. Compounds, coatings, and tapes are examples of types that can be used, the product you suggest is a rubber splicing tape, but manufacturers can give you information on what corrosion products they have. Reviewing the .10 and .12 sections in the Article for the specific raceway used can also give some guidance. What is considered suitable is often determined at the local level, based on soil makeup and soil resistance. In many areas steel rigid metal conduit is directly buried with no additional corrosion protection beyond that of the galvanizing. Field cut threads would also need corrosion protection as stated in 300.6(A).

NECA publishes the National Electrical Installation Standards (NEIS) which are a series of ANSI-approved performance and quality standards for electrical construction. NECA 101, Installing Steel Conduits, has information on corrosion protection in 4.6 including transitions from concrete to soil. NEIS can be purchased at:

neca-neis.org

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