Operation and Maintenance - hdbk109220040178

DOE-HDBK-1092-2004

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.

10.9.2.1.2 DESIGN AND CONSTRUCTION

NEC, Article 250, "Grounding" notes that grounds also provide:

1. Voltage limitation in case of lightning, line surges, or unintentional contact with higher

voltage lines

2. Stability of voltage to ground under normal operation

3. Facilitated overcurrent device operation in case of ground faults

4. A path to conductive objects that will limit the voltage to ground.

In R&D work there is one additional function for grounds: a common reference plane or system

ground return for electronic devices, circuits, and systems. (See Section 9.3) It is recognized

that such grounds are essential in some cases to control:

1. Noise associated with the primary power system:

a. Incoming on the line

b. Outgoing from local equipment

2. Ground wire noise

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