RMU Factory Acceptance Test (FAT) Checklist

RMU Factory Acceptance Test (FAT) Checklist

An RMU FAT is the last chance to catch mismatches before shipping. A good Factory Acceptance Test (FAT) verifies not only dielectric performance, but also functional operations, interlocks, and (if applicable) automation IO mapping.

This checklist can be used as a practical FAT template for utilities and EPC projects.

1) Nameplate and Documentation Verification

• rated voltage and insulation level
• rated current (busbar and functional units)
• short-time withstand and peak ratings
• configuration and single-line diagram match
• serial numbers and manufacturing data are recorded

2) Visual and Mechanical Inspection

• enclosure finish, corrosion protection, gaskets, locks
• cable compartment layout and clearances
• labels and safety markings
• earthing bar and bonding points

3) Dielectric and Electrical Routine Tests

Tests depend on standard and design, but typically include:

• dielectric withstand tests
• insulation resistance checks
• resistance measurements where applicable

4) Functional Operations and Interlocks

• switching operations for each functional unit
• earthing switch operation and indication
• mechanical interlocks and key interlocks
• door/access interlock behavior

5) Automation IO and Controls (If Applicable)

• motor operation and manual override
• position feedback signals
• fault indicator signals and reset logic
• RTU/SCADA mapping checks against IO list

6) Packing, Spares, and Delivery Items

• spare parts list and included spares
• special tools and operating handles
• installation manuals and wiring diagrams
• packing and transport protection

Internal Links

RMU category: Ring Main Units.

Related MV equipment: Switchgear.

Conclusion

A structured RMU FAT checklist reduces commissioning surprises and ensures the delivered RMU matches the tender. Focus on ratings verification, interlocks, functional operations, and IO mapping where automation is included. If the FAT evidence is complete and traceable, site work becomes much smoother.

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