General G0B: Electrical and tower safety
These are the 13 official questions in group G0B of the 2023–2027 General question pool, with the correct answer marked and a plain-English explanation of why it's right. The real exam asks one question from this group.
- G0B01Question 1
Which wire or wires in a four-conductor 240 VAC circuit should be attached to fuses or circuit breakers?
- AOnly the hot wires Correct
- BOnly the neutral wire
- COnly the ground wire
- DAll wires
Why: Only the hot wires get fuses or breakers.
- G0B02Question 2
According to the National Electrical Code, what is the minimum wire size that may be used safely for wiring with a 20-ampere circuit breaker?
- AAWG number 20
- BAWG number 16
- CAWG number 12 Correct
- DAWG number 8
Why: The NEC calls for at least #12 wire on a 20 A circuit.
- G0B03Question 3
Which size of fuse or circuit breaker would be appropriate to use with a circuit that uses AWG number 14 wiring?
- A30 amperes
- B25 amperes
- C20 amperes
- D15 amperes Correct
Why: #14 wire goes with a 15 A breaker.
- G0B04Question 4
Where should the station’s lightning protection ground system be located?
- AAs close to the station equipment as possible
- BOutside the building Correct
- CNext to the closest power pole
- DParallel to the water supply line
Why: The lightning protection ground belongs outside the building.
- G0B05Question 5
Which of the following conditions will cause a ground fault circuit interrupter (GFCI) to disconnect AC power?
- ACurrent flowing from one or more of the hot wires to the neutral wire
- BCurrent flowing from one or more of the hot wires directly to ground Correct
- COvervoltage on the hot wires
- DAll these choices are correct
Why: A GFCI trips when current flows from a hot wire directly to ground.
- G0B06Question 6
Which of the following is covered by the National Electrical Code?
- AAcceptable bandwidth limits
- BAcceptable modulation limits
- CElectrical safety of the station Correct
- DRF exposure limits of the human body
Why: The National Electrical Code covers your station's electrical safety.
- G0B07Question 7
Which of these choices should be observed when climbing a tower using a safety harness?
- AAlways hold on to the tower with one hand
- BConfirm that the harness is rated for the weight of the climber and that it is within its allowable service life Correct
- CEnsure that all heavy tools are securely fastened to the harness
- DAll these choices are correct
Why: Confirm the harness is rated for your weight and within its service life.
- G0B08Question 8
What should be done before climbing a tower that supports electrically powered devices?
- ANotify the electric company that a person will be working on the tower
- BMake sure all circuits that supply power to the tower are locked out and tagged Correct
- CUnground the base of the tower
- DAll these choices are correct
Why: Lock out and tag all circuits that power devices on the tower.
- G0B09Question 9
Which of the following is true of an emergency generator installation?
- AThe generator should be operated in a well-ventilated area Correct
- BThe generator must be insulated from ground
- CFuel should be stored near the generator for rapid refueling in case of an emergency
- DAll these choices are correct
Why: Run a generator in a well-ventilated area to avoid carbon monoxide.
- G0B10Question 10
Which of the following is a danger from lead-tin solder?
- ALead can contaminate food if hands are not washed carefully after handling the solder Correct
- BHigh voltages can cause lead-tin solder to disintegrate suddenly
- CTin in the solder can “cold flow,” causing shorts in the circuit
- DRF energy can convert the lead into a poisonous gas
Why: Lead from solder can get into food if you don't wash your hands.
- G0B11Question 11
Which of the following is required for lightning protection ground rods?
- AThey must be bonded to all buried water and gas lines
- BBends in ground wires must be made as close as possible to a right angle
- CLightning grounds must be connected to all ungrounded wiring
- DThey must be bonded together with all other grounds Correct
Why: Lightning ground rods must be bonded together with all other grounds.
- G0B12Question 12
What is the purpose of a power supply interlock?
- ATo prevent unauthorized changes to the circuit that would void the manufacturer’s warranty
- BTo shut down the unit if it becomes too hot
- CTo ensure that dangerous voltages are removed if the cabinet is opened Correct
- DTo shut off the power supply if too much voltage is produced
Why: An interlock removes dangerous voltage when the cabinet is opened.
- G0B13Question 13
Where should lightning arrestors be located?
- AWhere the feed lines enter the building Correct
- BOn the antenna, opposite the feed point
- CIn series with each ground lead
- DAt the closest power pole ground electrode
Why: Lightning arrestors go where the feed lines enter the building.