What's Wrong Here?
Oct 26, 2007 11:52 PM, By Joe Tedesco, NEC Columnist
Hint: Fill it with ice.
Nicholas Volpenhein, a project manager with Volpenhein Brothers Electric in Cincinnati, came upon this icy installation, although it was not his company’s doing. “This is what happens when you forget to seal a conduit in a freezer,” he says.
What’s wrong with this picture? NEC 300.7, Raceways Exposed to Different Temperatures (A) Sealing, states: “Where portions of a cable raceway or sleeve are known to be subjected to different temperatures and where condensation is known to be a problem, as in cold storage areas of buildings or where passing from the interior to the exterior of a building, the raceway or sleeve shall be filled with an approved material to prevent the circulation of warm air to a colder section of the raceway or sleeve. An explosionproof seal shall not be required for this purpose."
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