Residential Wireman Electrician Practice Test Correct 100%

Conductors with _____ marked on the insulation are NOT approved for use in a wet location. - Answers 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? - Answers 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 _____. - Answers 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? - Answers 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 _____ . - Answers 6 inches free conductor is to be left at each junction box for splices or the connection of luminaires or devices. The intent of this rule is to ensure enough conductor slack for the terminal connections or splices to be made easily. In general, overhead service-drop conductors shall NOT be smaller than _____. - Answers 8 AWG copper overhead service-drop conductors to be not smaller than 8 AWG copper or 6 AWG aluminum or copper-clad aluminum. Do not get service-drop conductors, the overhead conductors between the utility electric supply system and the service point, confused with the service-entrance conductors, the conductors from the service point from the utility company to the service disconnecting means. When a galvanized eye-bolt is to be used as the point of attachment for an electrical service, the NEC requires the eye-bolt to be installed NOT less than _____ above finished grade. - Answers 10 ft. provide adequate vertical clearance of the conductors and prevent physical damage to the conductors and prevent persons from making accidental contact with the conductors which may create a shock hazard or electrocution. In no case shall the point of attachment of the service-drop conductors to be less than 10 ft. above finished grade. Why is electrical continuity required for metallic conduit? - Answers To establish an effective ground-fault path and facilitate the operation of the over-current protective device. Electrical continuity is required for metallic conduit to establish an effective ground-fault path and facilitate the operation of the overcurrent protective device. In dwelling units, receptacle outlets installed for countertop surfaces, must be located above, but NOT more than _____ above the countertop or work surface. - Answers 20 inches receptacle outlets installed for countertop or work surfaces in dwelling units may be located on or above, but not more than 20 in. above the countertop or work surface. The intent of this rule is to eliminate the use of unsightly extension cords (which reduces the amount of usable countertop space) on the countertop or work surface to supply cord-and-plug connected appliances. Also, receptacles located more than 20 inches above countertops or work surfaces may interfere with the cabinetry to be installed. When conductors are installed in a conduit or tubing nipple of _____ or less in length, the ampacity adjustment factors for more than three (3) current-carrying conductors in the raceway, are not required to be applied. - Answers 24 inches adjustment factors for more than three (3) current-carrying conductors in raceways shall not apply where the raceway is not more than 24 inches in length. Where more than 3 current-carrying conductors are installed in short lengths of conduit or tubing, the heating effect caused from the additional conductors is insignificant therefore, the allowable ampacity of the conductors is not greatly reduced. In compliance with the NEC, the total marked rating of a 120-volt, cord-and-plug-connected room air conditioner shall not exceed _____ of the rating of a branch circuit when lighting units, general-use receptacles, or other appliances are supplied from the branch circuit. - Answers 50% the special provisions for room air conditioners which are (1) rated not over 250-volts ac, single-phase and (2) which are cord-and-attachment plug connected. In order to prevent overloading the branch circuit, as per Section 40.62(C), the total rating of the A/C unit shall not exceed 50% of the rating of a branch circuit where lighting units, general-use receptacles or appliances are also supplied. What shall not be located over the steps of a stairway? - Answers overcurrent devices "overcurrent devices shall not be located over steps of a stairway." This requirement address a serious safety issue. No one should be required to stand on different treads on a stairway to replace, repair, maintain, install, troubleshoot, or reset overcurrent devices in a panelboard or switchboard located in a stairway. Where a permanently installed outdoor swimming pool is located on residential or commercial properties, at least one (1) single-phase, 125-volt, 15- or 20-ampere receptacle shall be located not less than _____ from and not more than _____ from the inside wall of the swimming pool. - Answers 6 feet - 20 feet apply to the installation of wiring methods and equipment in or adjacent to permanently installed swimming pools. each permanently installed swimming pool is to be provided with at least one (1) single-phase, 15- or 20-ampere, 125-volt, receptacle placed not closer than six (6) feet from the pool and not more than twenty (20) feet from the pool. This requirement allows ordinary appliances such as a radio, to be safely plugged in and used near the pool, but avoids the need for extension cords in the pool vicinity. Be advised the receptacles must be provided with Metal water pipes installed in or attached to a building or structure shall be bonded to _____. a. the service equipment enclosure b. the grounded conductor at the service c. the grounding electrode conductor d. any of the above - Answers Any of the above