Journeyman Practice Test Questions and Answers

Journeyman Practice Test Questions and Answers Conductors with _____ marked on the insulation are NOT approved for use in a wet location. -Answer-THHN conductors with THHN insulation are approved for use in dry and damp locations only and conductors with THWN, THHW, and THW insulation are recognized for use in dry and wet locations. Given: A one-family dwelling unit with a demand load of 200 amperes is supplied with a 120/240 volt, single-phase, electrical system from the local utility company. What is the MINIMUM size aluminum THW conductors required for use as service-entrance conductors for this residence? -Answer-4/0 AWG one-family dwelling 120/240 volt, single-phase, service-entrance conductors to be sized at an ampacity of not less than 83% of the service rating. Therefore, 200 amperes x 83% = 166 amperes; size 4/0 AWG THW aluminum conductors with an allowable ampacity of 180 amperes should be selected for this dwelling. Where a 150 kVA, single-phase transformer having a secondary voltage of 120/240 is installed at a multi-family dwelling, the full-load current rating, in amperes, of the secondary is _____. -Answer-625 amperes To find the full-load current rating of the single-phase transformer apply the single- phase current formula as shown:I = (150 kVA x 1000) / 240 volts = 15,000/240 = 625 amperes Which one of the following listed circuit breakers is NOT a standard ampere rating? - Answer-75 amperes the standard ampere ratings for fuses and circuit breakers. A circuit breaker with an ampere rating of 75 amperes is not a standard ampere rating. The MINIMUM length of free conductor to be left at each junction box for the purpose of splicing conductors, or making connections to illuminares or devices shall be _____ . - Answer-6 inches