The installation-quality multiplier

You can buy a million euros of Ex-certified equipment. If the installation is sloppy — wrong cable gland, missing stopping plug, broken equipotential bonding — the certification is void in practice and the area is not safe.

IEC 60079-14 is the installation discipline that turns certified equipment into a certified installation.

The 5 deliverables of a compliant Ex installation

1. Area Classification Document (per IEC 60079-10-1/2) — already exists from upstream
2. Equipment list with Ex marking compliance — each device matches its zone
3. Installation drawings — including cable routing, segregation, bonding
4. Ex Register — operational document for inspection regime
5. IS Loop documentation — for every IS circuit, the calculation showing entity parameter compliance (Ui ≥ Uo, etc.)

These deliverables are auditable and required by ATEX 99/92/EC (workplace directive). Missing any of them = legal non-compliance.

Cable gland selection — the most common error

The cable gland on every entry point of every Ex enclosure must be certified for that protection method and that enclosure. Common mistakes :

Mistake 1 : Generic compression gland used on Ex d enclosure. Ex d requires a barrier gland (compound-filled) if the cable is “indirect entry” — i.e., the cable doesn’t go directly outdoors and could carry hot gases internally.

Mistake 2 : Stopping plug missing on unused entry. Every unused entry must be plugged with a certified stopping plug matching the enclosure protection method.

Mistake 3 : Wrong size gland. Glands are sized to cable OD. A loose gland is not sealed properly. A too-tight gland damages the cable jacket. Both = compromised certification.

Mistake 4 : Gland not torqued to specification. Compression glands need specific torque values to seal correctly. Eyeballing is not sufficient.

IS loop documentation in practice

Every IS loop has a documentation file with :

Loop : PT-101 / Pressure indication on T-101
─────────────────────────────────────────────

Field device (Zone 1)
  Manufacturer / Model : Endress+Hauser Cerabar M PMC51
  Certificate : KEMA 14 ATEX 0123 X
  Entity parameters :  Ui = 30V    Ii = 100mA   Pi = 0.75W
                       Ci = 15 nF   Li = 200 µH

Cable (in IS tray, blue jacket)
  Type / Length : H05V2-K 2×1.5 mm² / 200 m
  Capacitance contribution Cc : 200 m × 100 pF/m = 20 nF
  Inductance contribution Lc : 200 m × 1 µH/m = 200 µH

Barrier / Isolator (in safe area cabinet C-101)
  Manufacturer / Model : Pepperl+Fuchs KFD2-STC4-Ex1
  Certificate : KEMA 13 ATEX 0456 X
  Entity parameters :  Uo = 26V    Io = 80mA    Po = 0.52W
                       Co = 240 nF  Lo = 4 mH

VERIFICATION
  Ui ≥ Uo :   30V ≥ 26V  ✓
  Ii ≥ Io :   100mA ≥ 80mA  ✓
  Pi ≥ Po :   0.75W ≥ 0.52W  ✓
  Ci + Cc ≤ Co :   15+20 = 35 nF ≤ 240 nF  ✓
  Li + Lc ≤ Lo :   0.2+0.2 = 0.4 mH ≤ 4 mH  ✓

Conclusion : Loop is intrinsically safe per IEC 60079-25.

Designed by:  [name]   Date: [date]
Reviewed by:  [name]   Date: [date]

Every facility maintains hundreds to thousands of these IS loop documents in a controlled file system (often the MES or a dedicated Ex management software).

Equipotential bonding — invisible but critical

In hazardous areas, all metallic parts (process piping, structural steel, motor frames, control panels, cable trays) must be bonded together through a continuous low-resistance path. Reasons :

• Prevents static charge buildup (static spark = ignition source)
• Prevents stray currents from external faults running through the Ex area
• Provides reliable earthing for fault-current protection devices

Typical requirement : < 1 ohm resistance between any two bonded points. Verified by ohmmeter measurements during commissioning and periodic inspections.

Missing bonding strap on a single process flange in a Zone 1 area = legal non-conformity. Easy to miss visually, easy to catch with proper inspection regime.