Best Practices for Junction Box Installation
It is not uncommon in industry to find a junction box or switch box enclosure with water seeping in, especially when an entry or exit is made on the side or top. Often water pours out when the analyst opens the enclosure. Proper planning of conduit and cord grip installation will help installers and end users avoid problems of water ingress.
Positioning the Box
When selecting where to mount the box, regardless of whether it is a switch box, cable reduction box, or one of the many CTC enclosures, choosing a spot where there are no active sprays or wash-downs is encouraged.
CTC does not recommend putting holes in the top of any enclosure due to access and moisture concerns (shown below). Because of this, when possible, the conduit should only be brought into an enclosure through the bottom of the box, even if it means running the cable around the entire side of the enclosure.
Proper running of the conduit is not the only consideration, as even conduit can fill with moisture over time and still force fluid into the enclosure. To avoid this, drill a small hole in the conduit at the lowest point directly below the enclosure.
Other Considerations
Sometimes the internal architecture of the box forces cable entries into different configurations, or forces the placement of some of the cable entries or exits onto a less desirable location such as the side of the box. In these instances, proper installation of the cables is a must. Thoroughly tighten all cord grips where used and ensure some kind of low-point drain for all conduits.
