In industry, 30 volts is generally considered to be a conservative threshold value for dan- gerous voltage. The cautious person should regard any voltage above 30 volts as threatening, not relying on normal body resistance for protection against shock. That being said, it is still an excellent idea to keep one’s hands clean and dry, and remove all metal jewelry when working around electricity. Even around lower voltages, metal jewelry can present a hazard by conducting enough current to burn the skin if brought into contact between two points in a circuit. Metal rings, especially, have been the cause of more than a few burnt fingers by bridging between points in a low-voltage, high-current circuit.
References and Further Reading:
Also see:
- Electrical Motor Controls and Protection Handbook
- Instrument Transformer Safety
- Variable Frequency Drives