Power Supply Interface Between Utility Systems and R&D Equipment

DOE-HDBK-1092-98

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 NEC-

compliant 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 tray-

rated cable types are not available which meet the technical requirements of the installation, the non-

tray-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.

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