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Korean Electrician (전기기능사) Study Guides
Plain-language guides to the wiring and concepts behind the Korean Electrician practical and written exams. Read them before you wire in the simulator, or whenever a concept needs a refresher. All free, no login.
What Are a-Contacts and b-Contacts? Sequence Control Basics The starting point of the Korean Electrician practical exam, explained with diagrams — the three-phase supply and wire colors, the difference between an a-contact (NO) and a b-contact (NC), and how push-buttons and the red/green convention work. What Is an 8-Pin Relay? Pinout and How the Coil Flips the Contacts The 8-pin relay of the Korean Electrician practical exam, explained with diagrams — the coil (2·7) and two contact sets (1-3-4 / 8-6-5), how energizing the coil moves the contacts, and why the timer, flicker relay, and floatless switch all share the same socket. What Is a Self-Holding Circuit? Principle and Wiring Explained Understand the self-holding (latch) circuit at the heart of the Korean Electrician practical exam — with diagrams. The parallel a-contact principle, the start/stop formula, and how it maps onto a magnetic contactor (MC). MCCB and Fuse — the Panel's Two Protectors The start of the main circuit on the Korean Electrician practical exam, explained with diagrams — the MCCB (molded-case breaker) versus the fuse, their input/output terminals, and how the wire color flips at the fuse from the main circuit (brown/black/gray) to the control circuit (yellow). What Is an MC (Magnetic Contactor)? 12-Pin Main and Aux Contacts The MC (magnetic contactor), the key part of the Korean Electrician practical exam, explained with diagrams — the coil (6·12 / A1·A2), the main contacts (1-7·2-8·3-9) that feed three phases to the motor, and the aux contacts (4-10 a · 5-11 b) used for self-hold and interlock. Motor + Terminal Blocks (TB10·TB4) — the Panel Boundary The motor's U·V·W·PE terminals and the terminal blocks (TB10·TB4) of the Korean Electrician practical exam, explained with diagrams — how a 3-phase motor spins, why swapping two phases reverses it, and the terminal-block ordering rule (left→right / top→bottom, L1·L2·L3·PE) that disqualifies you if broken. What Is an EOCR (Overload Relay)? Main-Current Pins and Trip Contact (10·4·5) The EOCR (electronic overload relay) of the Korean Electrician practical exam, explained with diagrams — the main-current pins the motor current passes straight through (1·2·3 → 7·8·9), the trip contact that sends the overload signal out (10 COM · 4 NC · 5 NO), the "overload → auto-stop" wiring, and the manual-reset rule. What Is a Timer (T) Relay? Coil (2·7) and Timed Contact (8·6·5) The timer (on-delay relay) of the Korean Electrician practical exam, explained with diagrams — the same 8-pin socket and coil (2·7) as the relay, the timed contact that flips only after a set delay (8 COM · 6 timed-NO/delayed-ON · 5 timed-NC/delayed-OFF), and how on-delay (TON) operation works. Korean Electrician Control-Panel Layout — 400×420 Board and ±5mm Tolerance The part-placement rules for the Korean Electrician practical control panel (400 × 420 mm plywood), explained with a diagram — ±5 mm tolerance inside the board / ±30 mm outside, left-right symmetry and row/column alignment, terminal blocks at the edges, wiring lanes, and the accumulated-dimensional-error disqualification thresholds. Practical-Exam Wiring Rules — Two Wires per Terminal and Route-Via The Korean Electrician practical exam grades how you wire — max two conductors per terminal and right-angle runs only. This guide covers the route-via (경유 결선) technique for a third connection and the wire-colour convention by circuit type. Korean Electrician Public Problem 14 — Main Circuit (Motor Forward/Reverse) The main-circuit wiring of Public Problem 14 (motor forward/reverse) of the Korean Electrician practical exam, explained with a diagram — the shared POWER→MCCB→EOCR feed, the two motor branches off EOCR into MC1·MC2, the PE ground bus that bypasses the breaker, and the control-supply tap — all 22 conductors by color and terminal. Korean Electrician Public Problem 14 — Control Circuit (Automatic Forward/Reverse) The control-circuit wiring of Public Problem 14 (motor forward/reverse) of the Korean Electrician practical exam, explained with diagrams — the operation sequence, the schematic's top/bottom/middle paths, the SPDT structure of this problem's new part (the limit switch), and the MC interlock whose omission causes a 3-phase short and disqualification. Korean Electrician Public Problem 1 — Full Wiring Walkthrough A diagram-led breakdown of Public Problem 1 of the Korean Electrician (전기기능사) practical exam — device layout, panel interior, the main circuit (MCCB·EOCR·MC), the control circuit (self-hold, selector, flicker, floatless), and the mistakes that fail you. Korean Electrician Conduit Finishing — Pipe, Saddles, and Pulling Wires The conduit work that connects a finished control panel to the field, explained with diagrams for the Korean Electrician practical — the box-first work order, rigid PE pipe vs flexible CD conduit, the two saddle-spacing rules, the 4-core power cable, and pulling wires through the conduit.