10.9.1.2.1 DESIGN AND CONSTRUCTION AS AN INTEGRAL PART OF EQUIPMENT

If the AHJ determines that wiring is an integral part of an apparatus (e.g., instrumentation interconnections), then the wiring methods used should be evaluated by the AHJ as providing safe operating conditions. This evaluation may be based on a combination of standards and engineering documentation where appropriate. Such an evaluation should consist of an analysis of all stresses imposed on any electrical conductive elements, including, but not limited to electrical, magnetic, heating, and physical damage potential. The wiring methods selected must mitigate to the greatest practical extent any undesired effects of a failure sequence.

If cable trays are used as mechanical support for experimental circuits, they should be solely dedicated to this use and appropriately labeled. Any such use must be analyzed for detrimental heating effects of the proposed configuration.

10.9.1.2.2 POWER SUPPLY INTERFACE BETWEEN UTILITY SYSTEMS AND R&D EQUIPMENT

Utility supply voltages should be brought as near to the utilization equipment as possible using NECcompliant wiring methods.

Any temporary wiring methods used (e.g., extension cords) should be approved by the AHJ for a specified limited time.

Flexible cords and cables should be routed in a manner to minimize tripping hazards.

The conventional use of cable trays is defined in NEC Article 318. If power cables are placed in a cable tray used for control and signal cables, separation shall be provided according to the NEC Article 318. Certain experimental configurations or physical constraints may require the unconventional application of cable trays. Only the AHJ may approve these unconventional applications. If deemed necessary, enhanced fire protection or other safety measures shall be used to ensure safety to personnel and equipment.

For coaxial, heliax and specialty cables used for experimental R&D equipment, where NEC trayrated cable types are not available which meet the technical requirements of the installation, the nontray-rated cables shall be permitted with the approval of the AHJ. If deemed necessary, enhanced fire protection or other safety measures shall be used to ensure safety to personnel and equipment.

When metallic cable tray is being used, it shall be bonded to the equipment grounding system, but should not be relied upon to provide the equipment ground. The experimental equipment must be appropriately grounded by some other method.

10.9.1.3 OPERATION AND MAINTENANCE

The operation and maintenance of R&D systems which use wiring methods that are not anticipated by the NEC require special considerations from all personnel. The AHJ evaluation for safe operating conditions must include a review of unique features in the engineering documentation.

10.9.2 UNCONVENTIONAL PRACTICES

R&D performed by DOE contractors often incorporates the design of specialized equipment resulting in the need for specialized grounding and the use of materials and components in an unconventional manner. Even with these experimental needs and special design considerations, the maximum safety of personnel and equipment still needs to be ensured. The practice of using materials or components for purposes other than originally designed needs special consideration in their use, identification, personnel protection, and equipment protection.

10.9.2.1 GROUNDING

10.9.2.1.1 HAZARDS

The lack of proper grounding can cause electrical shock and/or burns to personnel. The NEC and NESC define legally-required grounding. To mitigate potential hazards, grounding shall be provided in accordance with the NEC and NESC.