National Electrical Installation Standards

Standards as High as Your Own

Thursday, September 28, 2017


Where in the code can I find an answer to the following: Can I use a plug-in transformer that is identified as "dry location use only" outside in an outlet fitted with a weatherproof "in use cover"?

Joseph Graham



Hey Joseph thanks for your question. The definition of Location, Dry in Article 100 states that it is not normally subject to dampness or wetness. The word weatherproof is also defined in Article 100 as being constructed or protected so weather exposure will not interfere with the successful operation. It does not indicate that it will keep all moisture or dampness out. It is somewhat of a judgment call but it seems that moisture could be present so equipment that is identified for dry locations only would not be allowed. The manufacturer might be able to provide additional guidance. If they do, please send it in and we will share it with our readers.

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