Practical-Exam Wiring Rules — Two Wires per Terminal and Route-Via
The practical exam isn't only about whether the circuit works — it grades how you wired it. Start with the two rules beginners break most often: two wires per terminal, and right-angle routing.
At most two wires per terminal (DQ #13)
The cited exam instructions prohibit three or more conductors at one terminal. Actual terminals also have product-specific conductor type, size and capacity limits; two conductors are not automatically permitted on every product.
Horizontal/vertical, right-angle only (DQ #14)
- Run straight along the horizontal lane between parts,
- turn 90° where you need to change direction,
- travel the vertical channel in the left/right margin specified by the drawing, then turn 90° once more onto the terminal.
- ❌ No diagonal shortcuts. ❌ No vertical run plowing between two parts.
When you need a third connection — route-via
If three points share one electrical node but the terminal is already full, route through a suitable terminal on the same electrical node that still has capacity.
- First prove that the destination is on the same electrical node, with no switch, coil or other component between it and the original connection. Then check terminal capacity.
- Current rides the wire already on that terminal onward to the destination.
- As a result no terminal ever carries more than two wires.
Korean trade calls this 경유 결선 (route-via). The daisy-chain analogy helps, but the term used here is route-via.
Wire-colour convention
Colour is chosen by the circuit a conductor serves, not by its endpoints.
| Category | Circuit | Wire colour |
|---|---|---|
| Main circuit | L1 | Brown |
| Main circuit | L2 | Black |
| Main circuit | L3 | Grey |
| Control circuit | control wire | Yellow |
| Protective earth | PE (ground) | Green-yellow |
Common mistakes
- Forcing a third wire onto the same terminal → route it via a sibling instead.
- Picking any nearby terminal to route through → it must be a free terminal on the same electrical node.
- Colouring by endpoint → colour follows the circuit type.
Next
With placement rules and wiring rules in hand, apply them on a real problem — Public Problem 14: main circuit (two-motor control). You'll see exactly where the 2-wire cap and route-via bite at EOCR's outputs.
Try it yourself
Open the practical project list →
Check your understanding
Question: Are correct colors and terminal counts sufficient after rerouting?
Answer: No. Preserve the same electrical node and check termination quality as well.
Practice path and references
The practical project list may require sign-in. Create a project, choose a task and place the relevant components, then compare the contact/wiring paths explained here. The link does not preload a specific completed circuit.
Reference: Q-Net public-problem notice, 2025-08-04 edition, problem 14 pages 11-1 to 11-4 (work/wiring instructions) and 11-9 (component diagrams). Read the original for each task and any amendments. Site examples are distinct from general installation design requirements.