Q: Your literature shows that the ST-U Universal Temperature Sensor housing is rated NEMA 3R. How can that be? It comes with a big nasty hole in the top and only a star bushing to plug it up!

A: Turn it over so the hole faces down, and you’ve got a NEMA 3R housing (unless you’re in a location where the rain falls up). The hole in the Model ST-U package is designed to accept a conduit connector, and as long as the conduit entry is below the point of any wiring connections within, the NEMA standard is met. It’s actually a good idea to have a hole in the bottom side of any outdoor enclosure to allow condensation to drain out, so the preferred conduit connector would not be a gasketed, liquid-tight type. If you’re not using conduit in an outdoor application, a strain relief grip or other cable connector fitting is recommended to keep spiders and wasps from making a home in the sensor housing.

The star bushing is for indoor use. It provides for easy ingress of cable and a moderate degree of strain relief in areas where insect invasion is not likely.