Fasteners are part of an explosion-protected enclosure, not generic workshop consumables. Their strength, geometry and engagement help the assembly retain the construction assessed by the certificate.
Decide whether a fastener is acceptable
| Check | Acceptable evidence | Stop work when |
|---|---|---|
| Identity | Drawing, parts list or manufacturer instruction | Selection is based only on visual similarity |
| Thread | Correct form, pitch and sound mating thread | Stripping, cross-threading or uncertain engagement exists |
| Strength/material | Marking and traceable specification | Grade or corrosion compatibility is unknown |
| Assembly | Approved tightening sequence/method | Lubricant or torque basis is improvised |
Do not drill, enlarge or substitute a different head style to make a replacement fit. Damage around a tapped hole or enclosure joint requires an approved repair disposition, not a larger bolt chosen on site.
Inspection after assembly
Clean mating surfaces using the motor instructions. Keep paint, sealant and debris away from flamepath interfaces. Confirm every required fastener is present, seated and accessible, and that covers close without forcing or misalignment.
Photograph the completed assembly and retain replacement traceability with the motor’s certificate and maintenance history. For uncertain cases, involve a competent Ex repair organization or the manufacturer before return to service.
Related reading: how to verify an Ex certificate and explosion-proof motor marking.