The purpose of this Safety Topic is to communicate the importance of testing and verifying voltage prior to working on energized lines, cables or components. When working on de- energized equipment, it is critical to never assume electrical power is off, always use an electrical test instrument to prove the line is de-energized and apply grounds. Cables and equipment shall be considered energized and worked with adequate protective devices until it has been tested de- energized with an approved device for indication of voltage and grounded with approved ground devices. The NECA red book and the SCE APM state the following:
NECA Red Book Section 7.05 Working on Cable or Apparatus (f):
The cable or apparatus shall be considered energized and worked with adequate protective devices (rubber gloves shall not be considered to be suitable devices on voltages in excess of 7,500 volts) until it has been:
- Tested with an approved device and proven to be de-energized.
- Grounded from all possible sources of power (Including transformers and secondary backfeed)
- Proved de-energized at the work location
- Where cables are not permanently identified by tags or otherwise, diagrams and information establishing positive identification and position of the cables shall be supplied to the workers
SCE Accident Prevention Manual: 303 Energizing Equipment
- No new piece of cable or switching device shall be energized until it has been positively identified by tags or other approved marking procedures.
- No piece of equipment shall be energized until all terminals, cables, and positions have been safe ended, end belled, or otherwise protected in a way that would prevent a short circuit, ground, or personal contact.
- Employees shall not enter a structure or enclosure where new, rebuilt, or modified high- voltage cable or equipment has been energized for the first time until the cable or equipment has been energized for a minimum of five minutes.
When testing, it is important to use clear communication with each member of your crew whether it is the person working next to you, the foreman, an employee inside a vault, or from pole to ground. Also, have a second person verify readings and prove taping. All neutrals need to be identified and marked and DO NOT rely on existing marks
TEST – VERIFY VOLTAGE – MARK