Performing equipment evaluations, particularly equipment that has been moved from one facility to another facility, is critical to the early success of a project. The desired result is to pass the field evaluations and the electrical inspection by the Authority Having Jurisdiction (AHJ), ensuring the equipment is in compliance with the latest applicable electrical industry standards.
The purpose of these electrical inspections and tests is to assure that custom or non-certified equipment meets the requirements of the appropriate codes, safety orders, and industry standards. These examinations are typically required by the local building inspection when equipment has not been certified by a Nationally Recognized Testing Laboratory (NRTL) or other recognized testing agency.
Relocated equipment that has been previously evaluated presents certain challenges typically not encountered during an evaluation of newly installed new or used equipment. One of the unique challenges is determining if the existing short circuit current rating on the nameplate of the industrial control panel is equal to, or greater than, the available short circuit current at the point of connection at the new facility.
What electrical standards apply?
The appropriate product electrical safety standard is the primary standard used for evaluating electrical equipment. The applicable portions of several other standards are combined into the reference product standard where no single product standard exists.
What is inspected and tested?
- Nameplate information
- Component identification
- Damaged components
- Inspection of components for evidence of (NRTL) listing or recognition
- Guarding of live parts
- Grounding
- Overcurrent protection
- Wiring methods and ratings
- Safety interlocks and emergency off or emergency stop controls
- Environmental suitability
- Testing may include but not be limited to components heat rise, dielectric withstand, leakage current, interlock, and E-Stop functional testing
The following are commonly encountered discrepancies:
- Missing Short Circuit Current Rating on Equipment Nameplate
The short circuit current rating value (where required) shall be marked on the equipment nameplate.
- Missing Documentation
Documentation showing the available short circuit current calculation and the date it was performed shall be made available to those authorized to inspect the installation.
- Verification of Motor Protection
All motors installed in the system are required to be properly protected from overloads, short circuits, and faults to ground. The proper selection and installation of motor overcurrent and overload protective devices are paramount to ensure the safety of personnel and to protect the equipment from damaging faults.
- Ampacity of Supply Conductors
The minimum size of the industrial control panel supply conductors shall have an ampacity not less than 125% of the full-load current rating of all heating loads, plus 125 percent of the full-load current rating of the highest-rated motor, plus the sum of the full-load current ratings of all other connected motors and apparatus based on their duty cycle that may be in operation at the same time.
- Missing or Outdated Electrical Drawings
Electrical drawings of re-located equipment may not be readily available, are not updated with modifications that may have transpired with the equipment, or are not legible given the age of the equipment. Correct electrical drawings are required for all equipment. If they are not available or are inaccurate, an updated electrical drawing must be created before the equipment can be evaluated and labeled.
- Inaccurate or Insufficient Wiring
Wiring within re-located equipment is often modified from the original design. This can include the wiring in panels or within the interconnecting cables between the subpanels and components of the equipment. The wiring must be verified to be suitably sized, bundled, and have the appropriate insulation type for the application. Wiring that is not correctly rated, routed, and approved for the application can be damaged by conditions such as overcurrent, physical damage, and exposure to the environment.
- Manufacturer Interface
May be challenging and time-consuming should the manufacturer be overseas or not in business any longer, and technical information, including machine electrical drawings or a bill of material, are not readily available or obtained.
- Damaged Components
- Wiring exposed at strain relief bushings that is no longer secured at the jacket.
- Internal wiring not adequately trained and bundled in approved wireways.
- External wiring is not installed in an approved raceway.
- Enclosure door interlocks damaged and not operating correctly.
- Conduits, fittings, and various electrical components such as motor contactors, motor overload relays, and overcurrent protective devices damaged or not adequately secured to the enclosure wall.
- Suitability of Installation
When machinery is relocated, the location selected for the equipment to be installed also must be evaluated. Dusty environments or atmospheres where flammable gases or vapors are concentrated enough to produce an explosive or ignitable mixture must be taken into consideration to determine the suitability of the installation.
Other Discrepancies Found During an Equipment Evaluation
- Supplementary rated overcurrent protection devices used instead of branch rated overcurrent protective devices.
- Missing capacitor residual voltage discharge warning sign.
- Missing or improperly rated primary and secondary overcurrent protection for control power transformers.
- Motor overload relay or overcurrent protective devices missing or improperly sized.
- Missing or improperly rated overcurrent protection on variable frequency drives.
- Missing or incorrectly labeled control panel nameplates.
- Marking on equipment disconnects.
- Incorrectly colored wiring insulation.
- Missing hazardous voltage and arc flash warnings signs.
- Un-used exposed opening in equipment control panels.
Once the re-located equipment has been evaluated and verified to be in compliance with applicable electrical standards, the accredited organization performing the field evaluation will affix its label on the equipment, and a final report is issued to the AHJ and the client detailing the field assessment. Final approval is under the authority having jurisdiction.
Conclusion
Approval of electrical equipment and relocated electrical equipment in the workplace is required, so it is free from recognized hazards that are likely to cause death or serious physical harm to employees. Field evaluations are conducted to determine compliance with applicable latest revisions of the electrical codes or standards for unlisted electrical equipment, including one-of-a-kind, limited production, used, relocated, or modified products that are not listed or labeled under a full listing and certification program.