Safety Hooks

DOE-HDBK-1092-2004

3. Use automatic shorting devices that operate when the equipment is de-energized or when

the enclosure is opened, which discharges the capacitor to safe voltage (50 V or less) in

less time than is needed for personnel to gain access to the voltage terminals. It must never

be longer than 5 minutes.

4. For Class C equipment with stored energy greater than 10 J, provide an automatic,

mechanical discharging device that functions when normal access ports are opened.

5. Ensure that discharge devices are contained locally within protective barriers to ensure

wiring integrity. They should be in plain view of the person entering the protective barrier so

that the individual can verify proper functioning of the devices.

6. Provide protection against the hazard of the discharge itself.

10.10.1.2.2

SAFETY GROUNDING

1. Fully visible, manual grounding devices should be provided to render capacitors safe while

work is being performed.

2. Grounding points must be clearly marked.

3. Prevent transferring charges to other capacitors.

10.10.1.2.3

GROUND HOOKS

1. Conductor terminations should be soldered or terminated in an approved crimped lug. All

conductor terminations must be strain-relieved within 15 cm.

2. Ground hooks must be grounded and impedance should be less than 0.1 ohms to ground.

3. The cable conductor must be clearly visible through its insulation.

4. A cable conductor size of at least #2 AWG should be used, and the conductor shall be

capable of carrying the available fault current of the system.

5. Ground hooks shall be used in sufficient number to adequately ground all designated points.

6. Permanently installed ground hooks must be permanently grounded and stored in a manner

to ensure that they are used.

10.10.1.2.4 DISCHARGE EQUIPMENT WITH STORED ENERGY IN EXCESS OF 10 JOULES

1. A discharge point with an impedance capable of limiting the current to 500A or less should

be provided.

2. The discharge point must be identified with a unique marker (example: yellow circular

marker with a red slash), and should be labeled "HI Z PT" in large legible letters.

3. A properly installed grounding hook should first be connected to the current-limiting

discharge point and then to a low-impedance discharge point (< 0.1 ohm) that is identified

by a unique marker (example: yellow circular marker).

10-25