No announcement yet.

Class 1 Div 2 Junction Boxes

  • Filter
  • Time
  • Show
Clear All
new posts

    Class 1 Div 2 Junction Boxes

    I am working on a Class I Div 2 application with instrumentation/sensor wiring. All devices are 24VDC or 4-20ma It is my understanding that:[LIST][*]Any devices with contacts that can arc (pushbuttons, solenoids) will be explosionproof and have a explosionproof seal at the device end of the conduit.[*]Any junction boxes without active devices (terminals only) can be NEMA 4 or 4X.[/LIST]

    A couple of wrinkles:[LIST][*]For a XP device going to a junction box, is a second seal required at the junction box end of the conduit? It doesn't appear to be but would seem to be useful to prevent migration.[*]Is a NEMA 4/4X enclosure still acceptable if a NAMUR interface module (rated CL I Div 2) is installed?[/LIST]

    Question 1. No. There is no benefit sealing a non-explosionproof enclosure. See Section 501.15(B)(1). The key word is required.

    Question 2. If the device is suitable for Division 2, see Section 501.105.
    Robert B. Alexander, P.E.
    Answers based on 2017 NEC unless otherwise noted.