Design and Construction

DOE-HDBK-1092-98

5. Auxiliary and control power circuits can remain energized after the main power circuit is

interrupted.

6. When power supplies serve more than one experiment, errors made when switching between

experiments may create hazards to personnel.

7. R&D electrical apparatus may contain large amounts of stored energy, requiring fault

analysis.

8. Liquid coolant leaking from R&D electrical equipment may pose an electrical hazard to

personnel.

10.8.1.2

DESIGN AND CONSTRUCTION

In design and construction of R&D equipment, it is important to remember the following cautions:

1. Install only components essential to the power supply within the power-supply enclosure.

2. Provide appropriate separation between high-voltage components and low-voltage supply

and/or control circuits.

3. Provide to personnel a visible indicator that the power supply is energized.

4. Minimize the number of control stations and provide an emergency shutdown switch where

needed.

5. Where possible, avoid multiple-input power sources.

6. Apply a label containing emergency shutdown instructions to equipment that is remotely

controlled or unattended while energized.

10.8.1.3

OPERATION AND MAINTENANCE

Before working in a power-supply enclosure or an associated equipment enclosure, see Sections 2

and 7. Personnel should take the following precautions:

1. Implement lockout/tagout.

2. Check for auxiliary power circuits that could still be energized.

3. Inspect automatic shorting devices to verify proper operation.

4. Short the power supply from terminal to terminal and terminal to ground with grounding

hooks.

10.8.2 CONDITIONS OF LOW VOLTAGE AND HIGH CURRENT

10.8.2.1

HAZARDS

It is usual for R&D facilities to have equipment that operates at less than 50 V. Although this

equipment is generally regarded as nonhazardous, it is considered hazardous when high currents are

involved. Examples of such equipment are a power supply rated 3 kA at 25 V, a magnet power supply

with rated output of 200 A at 40 V, and a bus bar carrying 1 kA at 5 V.

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