Journeyman Electrician Practice Test 18

Question 1: A good grounding system can also protect the system from lighting effects.

• True
• False

Question 2: The resistance between a driven pipe or ground rod, and the earth should not exceed ............... ohms.

• 25
• 30
• 20

NEC Reference: NEC 250.84

Question 3: If a house having less than two branch circuits with an ampere rating of 25 ampere. what is the minimum wire size that can be used?

• No 8
• No 6
• No 10

Question 4: As per NEC, minimum ........................ size wire is required for overhead spas up to 50 ft.

• No 8
• No 10
• No 6

NEC Reference: NEC 225.6(a)

Question 5: If the service entrance current transformer has a turns ratio of 200:5. If the primary of  transformer has a current of a 100 amp what is its secondary current in amperes?

• 5 amps
• 10 amps
• 2.5 amps

Question 6: The standby power plant should be capable of delivering the full power within ............... sec of the general power failure.

• 60 sec
• 120 sec
• 90 sec
• 75 sec

Question 7: The emergency power plant one started by a loss of power must continue to run at least 60 minutes after the power is re-established in hospital.

• True
• False

Question 8: The power factor of a under excited synchronous motor is always.................

• unity
• leading
• unity

Question 9: Which of the following motor is most suitable for timing and signalling devices?

• reluctance motor
• D.C Series motor
• linear motor

Question 10: Regulating transformers in power system are used in power system to control ............................

• power factor
• load flow
• voltage