Ex d Cable Gland Selection — Complete Guide

Selecting the correct cable gland for an Ex d enclosure requires understanding the entry type, enclosure volume, gas group, and cable type. This guide covers every decision in the selection process.

Step 1 — Identify the Entry Type

Is the cable entry threaded (visible thread within the hole) or clearance (smooth bore)? This is the first decision:

• Clearance entry → barrier gland always required (regardless of volume or gas group)
• Threaded entry → proceed to Step 2

Step 2 — Check the Enclosure Volume

For threaded entries into Ex d enclosures:

• Volume ≤2 litres → non-barrier gland acceptable for SWA
• Volume >2 litres → barrier gland required for SWA

Step 3 — Verify Gas Group

The gland must be rated for the gas group of the area:

• IIA area → IIA, IIB, or IIC rated gland acceptable
• IIB area → IIB or IIC rated gland (not IIA)
• IIC area → IIC rated gland only — no exceptions

Step 4 — Accessories

For Ex d, the rules on accessories are the opposite of Ex e:

• No IP washer on threaded Ex d entry — it would interfere with the thread flamepath
• No external locknut on threaded Ex d entry
• Internal earth connection required — armour to earth tag inside the enclosure

Stopping Plugs for Unused Entries

Every unused cable entry in an Ex d enclosure must be sealed with a certified stopping plug — also referred to as a blanking plug or transit plug. The stopping plug must:

• Be rated for Ex d (ATEX/IECEx certified)
• Have minimum 5 full thread turns engagement
• Be rated for the correct gas group (IIC if in IIC area)