Grounding Stick
A grounding stick is used to ground a high-voltage circuit before touching it or leaving it unattended and exposed. The grounding stick must be left on the high-voltage terminal until the circuit is about to be re-energized. High Voltage DC sources require two different sticks. The first stick typically used is called a discharge stick. The discharge stick removes the stored energy through a resistor connected to ground.
Before touching a high-voltage circuit or before leaving it unattended and exposed, it must be de-energized and grounded with a grounding stick. The grounding stick must be left on the high-voltage terminal until the circuit is about to be re-energized.
Grounding sticks must be available near entrances to high-voltage areas. Automatic grounding arrangements or systems that employ audible warning tones to remind personnel to ground the high-voltage equipment are strongly encouraged for two-person operation, and are mandatory for one-person or unattended operation.
For systems with bare conductors at moderate voltages, the use of a grounding stick is strongly recommended, particularly if the setup contains energy-storage devices.
Modes of Operation
Two-person: Two-person operation is the normal mode of operation where high or moderated voltages are present. Allowed exceptions are:
- a) When all potentially dangerous voltages are confined inside a grounded or insulated box, or where the voltages are constrained in a shielded cable, or where there is no access to bare conductors
- b) When one-person or unattended operation setups have been designed and approved according to the rules set out in this document and with appropriate approval.
- c) It is presumed that both individuals participating in two-person operation will follow basic high-voltage safety procedures and will monitor each other’s actions to ensure safe behavior.
One-person: One-person operation of systems using high and moderate voltages with bare or exposed conductors, may be approved, after appropriate review and authorization, in order to provide for the efficient use of staff for long-term applications where it is judged that safety would not be compromised.
Unattended: It is recognized that in order to run efficient calibration services and maintain appropriate delivery schedules, unattended operation of systems using high and moderate voltages may be necessary. In such cases, unattended operation is permitted with appropriate review and authorization, for systems having no bare or exposed conductors, and where required warning signs, lights, and barriers are present.
Unattended operation of setups with bare or exposed conductors at high and moderate voltages may be necessary under special circumstances, such as for unusually long data acquisition periods. This is meant to be a rare occurrence. Should this mode of operation be frequently employed, then the apparatus should be modified to enclose all potentially dangerous voltages.
ASTM Standard F 711 specifies the stringent requirements for grounding sticks, and OSHA standards require that they be inspected and electrically tested every two years.
