Materials and Tools (Identification Questions)

The correct answer is "600 V PVC insulated PVC sheathed cable, flat type". V stands for vinyl (PVC) and F for flat, so VVF is a flat cable with PVC insulation and a PVC sheath. "600 V PVC insulated wire" is IV (insulated wire with no sheath), the round-type cable is VVR, and "PVC insulated drop wire" is the name of DV.

The correct answer is "Solid conductors 2.0 mm in diameter, with 3 cores". The size of a solid wire is shown by its diameter (mm), and "3C" means three cores. The option reading "2.0" as a cross-sectional area of stranded wire is wrong (area in mm², such as 5.5, is used for stranded wire). The option saying "3 m long" is wrong because "C" does not mean length. The option with 3.0 mm and 2 cores mixes up the order of the numbers.

The correct answer is "A cable has a sheath that covers the outside of the insulation". A conductor wrapped in insulation is an insulated wire; when a sheath (outer jacket) is added over that, it is a cable. The option about stranded vs. solid conductors is wrong: both come in solid and stranded types. The option about outdoors only vs. indoors only is wrong: insulated wires such as IV are used indoors, and cables can be used outdoors. The option about copper vs. aluminium is wrong: the conductor material is not what separates them.

The correct answer is "DV". DV is "PVC insulated drop wire" (引込用ビニル絶縁電線), made for overhead service drops. IV and HIV are insulated wires used indoors, for example inside conduit. VVR is a round cable, not an insulated wire.

The correct answer is "PVC insulated wire for outdoor use (OW)". Articles 158 and 159 of the Interpretation require "insulated wire (excluding PVC insulated wire for outdoor use)", so OW cannot be used. The 1.6 mm solid IV and the grade 2 PVC insulated wire (HIV) are insulated wires and solid wires of 3.2 mm or less, so they are allowed. The 5.5 mm² wire is stranded, so it is allowed.

The correct answer is "It gives off little halogen gas when burned". EM stands for eco-material. Its insulation and sheath are flame-retardant polyethylene, so it gives off little halogen-containing gas when it burns. The option saying both insulation and sheath are PVC describes VVF. The option about outdoor overhead lines describes OW; EM-EEF is a sheathed cable. The option about a soft wire for moving equipment describes cabtyre cable.

The correct answer is "VVF". It has a sheath, so it is a cable, and its cross-section is flat, so it is VVF. IV is just one conductor with insulation and no sheath. VVR is a cable with a round cross-section. DV is an insulated drop wire, not three wires lying in one flat sheath.

The correct answer is "1.2 mm". Article 159(2)(ii) requires metal conduit embedded in concrete to be at least 1.2 mm thick. 0.5 mm is for conduit 4 m or shorter without joints in dry, exposed places. 1.0 mm is for other places. 0.8 mm is one of the conditions for using Type 1 flexible metal conduit, not a value for metal conduit.

The correct answer is "600 V cross-linked polyethylene insulated PVC sheathed cable". C stands for cross-linked polyethylene insulation and V for a PVC sheath. Cables insulated with cross-linked polyethylene are covered by JIS C 3605 (600 V polyethylene insulated cables). The polyethylene insulated, flame-retardant polyethylene sheathed cable is wrong because its insulation is not cross-linked polyethylene and its sheath is not PVC. The round-type PVC sheathed cable is VVR, and PVC cabtyre cable is VCT.

The correct answer is "PVC cabtyre cable (VCT)". Cabtyre cable uses soft stranded conductors covered by a tough sheath, so it suits equipment that is moved during use (Article 8 of the Interpretation covers cabtyre cables). IV, OW and DV are insulated wires without a sheath and are not suited to wiring that moves.

The correct answer is "Threadless box connector". A threadless box connector joins the conduit to the box, and a locknut tightens it from inside the box. A TS coupling joins rigid PVC conduits together. A threadless coupling joins two threadless conduits. A normal bend is a curved piece of conduit for right-angle joints.

The correct answer is "Tighten it until the head twists off". The exam centre's defect criteria list "set screw not twisted off" on a threadless bushing or threadless box connector as a defect. Tightening lightly by hand, or relying on the locknut only, does not hold the conduit firmly. As for the option using glue: glue is used for rigid PVC conduit (TS couplings), not for metal conduit.

The correct answer is "To protect wire insulation at the conduit opening". An insulating bushing is fitted on the open end of a conduit so that the wire insulation is not damaged on the edge when wires are pulled in or out. Joining conduits in a straight line is the job of a coupling, fixing conduit to a structure is a saddle, and passing a pull line is a fish tape (呼び線挿入器).

The correct answer is "Entrance cap". An entrance cap is used on the end of a vertical conduit; its opening faces down, so rain does not easily get in. The terminal cap is used on horizontal conduit ends; on a vertical pipe water could enter. A universal fitting is used where exposed conduit turns a right angle, and a normal bend is a curved length of conduit.

The correct answer is "Universal fitting". A universal fitting is used where exposed conduit turns a right angle. A coupling joins conduits in a straight line, a saddle fixes the conduit to a structure, and a locknut is a nut that clamps a connector to the wall of a box.

The correct answer is "CD conduit is not self-extinguishing and is embedded in concrete". CD conduit is not self-extinguishing; under Article 158 of the Interpretation it must be embedded directly in concrete or placed in a dedicated non-combustible or self-extinguishing flame-retardant pipe or duct. The option saying CD conduit is only for exposed indoor runs is the reverse: CD conduit cannot be used on its own for exposed runs. The option saying PF conduit must not be embedded in concrete is wrong: PF conduit can be embedded in concrete and also used for exposed or concealed indoor runs. The option saying both are rigid and must be heated describes rigid PVC conduit; pliable conduit can be bent by hand.

The correct answer is "TS coupling". A TS coupling joins rigid PVC conduits with adhesive. A threadless coupling joins threadless steel conduits with set screws, a combination coupling joins different types of conduit (such as flexible metal conduit and steel conduit), and a straight box connector connects flexible metal conduit to a box.

The correct answer is "Combination coupling". A combination coupling joins two different kinds of conduit, such as flexible metal conduit and steel conduit. A TS coupling joins rigid PVC conduits, an entrance cap goes on the top of a vertical conduit, and a rubber grommet is used where a cable passes through a hole in a box.

The correct answer is "Rubber grommet". A rubber grommet (ゴムブッシング) is fitted into the hole to cover its edge so the cable sheath is not damaged. The defect criteria also list improper use of a rubber grommet. A locknut fixes connectors or conduit, a saddle fixes conduit or cable, and a normal bend is for right-angle conduit runs.

The correct answer is "No joints inside the conduit; join wires inside a box". Article 159 of the Interpretation says there must be no joints in the wires inside metal conduit (the same applies to plastic and flexible metal conduit). Joints are made inside an outlet box or similar. The other options (taping well, a short conduit, push-in connectors) all join wires inside the conduit, so they are wrong.

The correct answer is "Reamer". A reamer has a cone-shaped blade; it is turned with a brace (クリックボール) to remove burrs from the inside of the pipe. A hole saw cuts round holes in metal sheet, a pipe bender bends metal conduit, and a fish tape pulls a line through conduit.

The correct answer is "0.8 times". Article 158(3)(ii) sets the insertion depth between conduits, and between conduit and box, at 1.2 times the outer diameter or more, or 0.8 times or more when adhesive is used. 1.2 times is the value without adhesive. 0.5 times and 1.5 times do not appear in the Interpretation.

The correct answer is "Gas torch". Rigid PVC conduit is warmed with a gas torch to soften it before bending. A pipe bender bends metal conduit and cannot heat plastic pipe. A chamfering tool removes the sharp edge of a cut plastic pipe, and a pipe cutter cuts pipe.

The correct answer is "Knockout punch". A knockout punch punches large round holes in metal plate. An auger bit is for drilling holes in wood, not steel. A plastic pipe cutter cuts plastic conduit, and a wire stripper strips insulation from wires.

The correct answer is "Auger bit". An auger bit (羽根ぎり) drills holes in wood and is used with a brace or a drill. A reamer removes burrs inside metal conduit, a knockout punch punches holes in metal plate, and a pipe cutter cuts pipe.

The correct answer is "Hammer drill". A hammer drill (振動ドリル) adds a hammering action to rotation to drill concrete. An auger bit is for wood. A chamfering tool removes the edge of cut plastic conduit and a wire stretcher tightens overhead wire; neither drills holes.

The correct answer is "Fish tape". A fish tape (呼び線挿入器) pushes a coiled line through the conduit; the wires are then tied to it and pulled in. A bolt clipper cuts thick wire or bolts, water pump pliers are used for tightening locknuts, and a brace is a hand tool that turns reamers or auger bits.

The correct answer is "Crimping tool for ring sleeves". Ring sleeves are crimped with the crimping tool made for ring sleeves. The crimping tool for bare terminals looks similar but is for bare crimp terminals, not ring sleeves. Squeezing with pliers or water pump pliers does not give the required crimp. The defect criteria also treat improper use of the crimping tool as a defect.

The correct answer is "Water pump pliers". Water pump pliers have jaws that adjust in steps, so they can grip and tighten a locknut. A wire stripper strips insulation, a pipe cutter cuts pipe, and an electrician's knife is a blade for removing sheath or insulation; none of them can tighten a nut.

The correct answer is "Wire stripper". A wire stripper has blade holes for each wire size and strips the insulation. A bolt clipper cuts thick wire or bolts and cannot remove only the insulation. A reamer removes burrs inside conduit, and a pipe bender bends metal conduit.