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Friday, November 19, 2021
Question:
Hello,
What is the difference between watertight and waterproof? Seems as though they mean the same thing. What are your thoughts?
Marty Pease
A
Answer:
Hi Marty,
Thanks for asking. For proper application of the NEC, defined words and terms often clarify the meaning of the rules where they appear. There is a distinct difference between the two terms that are used in the NEC. The definitions and informational note in Article 100 are as follows:
Watertight. Constructed so that moisture will not enter the enclosure under specified test conditions.
Weatherproof. Constructed or protected so that exposure to the weather will not interfere with successful operation.
Informational Note: Rainproof, raintight, or watertight equipment can fulfill the requirements for weatherproof where varying weather conditions other than wetness, such as snow, ice, dust, or temperature extremes, are not a factor.