One way to prevent bad safety habits from creeping up on you is to think about just how dangerous electricity really is. Have you thought of these facts, lately?
- Safety grounds can be unsafe. First of all, make sure the safety ground is bonded to the same grounding system as the incoming power (e.g., bond it to the Equipment Grounding Conductor). Not doing this sets up dangerous differences of potential. Second, make sure the connections are good; one high-resistance connection is all it takes to produce a fatality.
- Circuit breakers do not provide personnel protection. Think about the common 20A circuit breaker. 10A flowing through your body will probably kill you, but it will never trip that breaker.
- The branch circuit breaker might not be the only energy source. There may be another, undocumented electrical energy source such as an unintended backfeed. Always confirm de-energization with a meter using the “positive confirmation” technique (measure a known voltage, measure the “dead” circuit, measure the known voltage again). Don’t forget about non-electrical energy sources, such as hydraulics, pneumatics, and springs.
- Insulated conductors can provide a lethal touch shock. Don’t touch energized conductors with your bare hands (only with properly rated gloves). One reason we do insulation resistance testing and other insulation integrity testing is conductor insulation can be damaged (e.g., a pinhole) or undergo severe deterioration such that it no longer effectively insulates.
Source: Mark Lamendola | Mindconnection