T0A - Safety
Technician Class
Power circuits and hazards: hazardous voltages, fuses and circuit breakers, grounding, electrical code compliance; Lightning protection; Battery safety
12 questions | Updated: Feb 19, 2026
Which of the following is a safety hazard of a 12-volt storage battery that lacks internal protection circuitry?
What health hazard is posed by electrical current flowing through the body?
In the United States, what circuit does black wire insulation indicate in a three-wire 120 V AC cable?
What is the purpose of a fuse in an electrical circuit?
Why should a 5-ampere fuse never be replaced with a 20-ampere fuse?
What is a good way to guard against electrical shock at your station?
Where should a lightning arrester be installed in a coaxial feed line?
Where should a fuse or circuit breaker be installed in a 120V AC power circuit?
What should be done to all external ground rods or earth connections?
What hazard exists when rapidly charging or discharging an unprotected battery?
What hazard exists in a power supply immediately after turning it off?
Which of the following precautions should be taken when measuring high voltages with a voltmeter?