Design and Construction - hdbk109220040192

DOE-HDBK-1092-2004

10.10.3.2

DESIGN AND CONSTRUCTION

When working with special conductors and connectors for R&D applications, the following

guidelines shall be implemented for design and construction:

1. Select cables that are listed by an NRTL for a given type of installation (such as in conduits,

trays, underground, or in an enclosure) whenever possible. Since cables used for R&D are

sometimes unique (such as some coaxial cables), they may not be available as NRTL listed.

In that case, obtain AHJ approval.

2. Where liquid- or gas-cooled conductors are used, sensing devices (temperature or coolant-

flow) shall be provided for alarm purposes or equipment shutdown if the cooling system

malfunctions. Provide adequate labeling, insulation, or other protection for metallic cooling-

water piping used as electrical conductors.

3. Provide engineering calculations to support overrating of conductors for any application.

Avoid conductor loops (wide spacing) between high-current supply and return conductors to

prevent voltage and current induction in adjacent circuits or structural members.

4. Ground coaxial cable shielding when possible. If test conditions require an ungrounded

shield, provide barriers and warning signs to notify personnel that the shield is ungrounded

and should be assumed to be energized. Provide suitable routing and additional protection

for coaxial cables used in pulsed-power applications where the braid of the coaxial cable

rises to high voltage levels.

10.10.3.3

OPERATION AND MAINTENANCE

Cable connectors and connections should be checked after installation, periodically, and should

be tightened as necessary. Special attention should be given to aluminum cable connections.

Ensure that charges are not built up on equipment that has been disconnected, such as vacuum

feed through systems.

10.10.4 INDUCTION AND DIELECTRIC HEATING EQUIPMENT

This section describes electrical hazards associated with induction heating, RF equipment, and

microwave equipment used in research. The hazards are mainly associated with high-

power/high-frequency RF generators, waveguides and conductors, and the working coils

producing high temperatures.

10.10.4.1

HAZARDS

1. RF power as high as 50 kW and frequency in the tens of kHz range to hundreds of MHz is

supplied from the RF and microwave generators. Being close to or making contact with an

unprotected coil, conductors or waveguide opening may result in severe body burns.

2. Dangerous voltages are present inside the power generators.

3. Dangerous levels of RF energy may be present in the laboratory.

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