[Class 2 Electrician Skills Examination] Published Question 13 [Automatic Flasher Circuit]

12/10/2025

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Target: Class 2 Electrician Skills Examination Published Question 13
What is the theme of this exam number?
- Correctly understand and wire the circuit in which an automatic flasher is replaced with a "terminal block"
- Make sure to connect the ground (earth) of the outlet with a grounding terminal securely.
- Learn the technique of inserting multiple VVF1.6s at the correct length into the terminal block and securely fixing them with screws (according to HOZAN Publication Problem 13).

Published problem 13 is a representative problem of the so-called "automatic flasher circuit."
However, instead of using a real automatic flasher, wire the terminal block to resemble the inside of the automatic flasher. If the structure of the circuit is unclear, it is easy to get lost in the double-track diagram stage, and construction time is lost all at once (from the HOZAN explanatory video). (Hozan)

Furthermore, since 2020, ``outlets with grounding electrodes'' have been included in the question, and published questions 3 and 13 are both asked about outlets with grounding electrodes (according to the explanation of the construction conditions on the qualification exam information site).
Therefore, the key to passing the exam is to remember how to properly route the ground wire (green or green/yellow) and how to connect it to the terminal block and outlet.

I've written it in a lot of detail because I'm assuming there are people who say, ``Even after looking at the official text, I don't know where to start...'' I would be happy if you could actually practice using your hands while reading the article.

Actually, I am also learning by summarizing things like this lol

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So, here you go.

Table of Contents

Tools needed for this exam

Here, we will organize the tools that you should have as a minimum for Publication Question 13. Once you have the tools, you can use them for other problems, so it will be much easier to learn if you have a complete set on Amazon or Yahoo! Shopping.

VVF stripper (1.6/2.0 combined type)
- Essential for quickly and accurately aligning exterior strips 5cm, 10cm, etc.
electrician knife
- Convenient for making fine adjustments that cannot be reached with a VVF stripper or making fine adjustments to the sheath.
Passed multi-tool (HOZAN)
・Crimp of ring sleeve
- Screwdriver assistance for fixing instruments
- Useful for detailed work such as bending and adjusting the tabs of the mounting frame (used for crimping problems with terminal blocks and adjusting the mounting frame in the HOZAN video).
Crimping pliers (for ring sleeves)
・You may be able to use a multi-tool instead, but using a dedicated tool will stabilize the amount of force applied.
Screwdriver (No. 2 Phillips)
- Compatible with almost all terminal blocks, lamp receptacles, outlets, etc.
Pliers/Radio pliers
- Assists in bending core wires and stranded wires (bending VVF core wires, not stranded wires).
Scale (ruler) or “instrumental dimensioning” techniques
・The Gamidenki channel introduces a method to measure the distance between devices using the devices themselves. (Gamidenki channel)

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Materials to be prepared for this exam

We will organize a typical structure based on the material example of HOZAN's published problem 13 (the length may change slightly from year to year, but the idea is the same).

VVF1.6-2C (white/black)
・For general circuits such as power supplies, lamps, switches, terminal blocks, etc.
・Length example: 350mm x several pieces, 250mm x several pieces, etc.
VVF2.0-2C (white/black)
・For outlets with grounding terminal (2.0mm² is standard for 15A support)
Bare copper wire 1.6mm (or green IV wire)
・Used as a grounding wire (earth)
lamp receptacle
Switch (single cut switch)
Grounded outlet
Terminal block as a substitute for automatic flasher (uses 4 of the 6P terminal blocks)
joint box, outlet box
Ring sleeve (small/medium)
Plug-in connectors (for 3 wires, 2 wires, etc.)

HOZAN's explanation explains how to determine the length for each location, such as 5cm for the exterior of the VVF used for the terminal block and 10mm for the core wire, and 10cm for the exterior and 20mm for the core on the joint box side (for example, strip the length at 20mm and cut back to 12mm for the plug-in connector).
This method of ``fixing rules for each location'' is very effective in speeding up the actual exam and preventing mistakes.

Main flow (including how to use the passing multi-tool)

The overall flow of Publication Question 13 will be roughly organized into four phases.

Confirmation of drawings and construction conditions
- The construction conditions will specify which number and color wires should be placed on the terminal block (for example, black for No. 1, two white wires for No. 2, etc.).
- Also check the ground connection position of the grounded outlet.
Creating a double line diagram
- Black: Non-grounded side of power supply (L)
- White: Ground side (N)
- Green: Ground wire (E)
  While adhering to the basic color coding, write down how switches, lamps, and outlets are connected across the automatic flasher (terminal block).
Dimensioning and cutting out the cable
- The basic rule is to cut the length by adding the distance between the centers of the fixtures + 100mm from the start (example: 250mm between the fixtures + 100mm from the start = 350mm). (Gamidenki channel)
- If you stick to the rule that the terminal block side has an exterior of 5cm and the box side has an exterior of 10cm, you will have less to think about.
Wiring/equipment installation/finish confirmation
- Wiring the terminal block and automatic flasher substitute part
- Wiring lamps, switches, and grounded outlets
- Ring sleeve crimping and plug-in connector connection at joint part
- Defect check after finishing

Among these, the ``passing multi-tool'' is particularly useful in the following two areas.

Crimp ring sleeve
- When crimping the small sleeve/medium sleeve at the predetermined ``○'', ``small'', and ``medium'' marking positions, you can do it in one go by using the markings on the multi-tool (crimping work in the HOZAN video).
Fine adjustment of the mounting frame
・After fixing the lamp or outlet to the mounting frame, bend the claws of the frame so that they stick firmly to the board. You can use the tip of a multi-tool to bend them neatly (introduced in the HOZAN explanation along with the idea of ``marking circles at the three fixtures in the mounting frame''). (Hozan)

As a blog, if you casually place a product introduction link for "HOZAN Pass Multi-Tool" around here, it will be easier for readers to imagine, and it will also be natural for affiliate marketing.

How to draw wiring diagrams and things to be careful about

1. Understanding automatic flashers (terminal blocks) from the inside

In HOZAN's explanation, the contents of the automatic flasher are organized as follows (using a terminal block).

Terminal 1: Power side black wire (L)
Terminal 2: Connect the white wire (N) on the power supply side and the white wire (N) on the load side.
Terminal 3: Load side black wire (lamp side L)

In other words, an automatic flasher is a machine that "switches the power supply L and sends it to the lamp L," and the structure is such that the N simply passes through.
In a double-line diagram, it is easier to understand if you divide the terminal block into these three terminals and write them as "1 → internal switch → 3" and "2 is the confluence of the white lines."

If you don't understand this

Failure to bundle the white wires to terminal 2
I accidentally put the white wire of the lamp in the wrong joint.

This can easily lead to fatal flaws, so we recommend drawing a simple circuit diagram yourself and checking it.

2. Double-line diagram of a grounded outlet

When writing an outlet with a grounding terminal on a double-track diagram, keep in mind the following three points (from the construction condition explanation and terminal display).

Power supply L (black) → non-ground terminal of outlet
Power supply N (white) → Ground terminal of outlet
Ground wire (green) → Ground terminal of outlet (symbol: ⏚)

On the double-track diagram, draw a circle near the outlet,

Black wire: From switch (or terminal block) to outlet
White wire: From power supply N to outlet
Green wire: From ground bus bar to outlet

If you make sure you don't get lost with the arrows, it will be much easier during construction.

3. Cable size and color coding rules

Lamp circuit: 1.6mm² (VVF1.6-2C)
Outlet circuit: 2.0mm² (VVF2.0-2C)

is the basic rule (because 2.0mm² or more is required for a 15A circuit in a typical home). The electrical equipment technical standards determine the selection of conductor cross-sectional area based on the relationship between circuit current and allowable current, but in the two types of skill tests, it is most important to ``follow the wire type specified for each question'' (general design rules based on electrical equipment technical standards and interpretations).

At the double-line diagram stage, if you draw only the lines leading to the outlet in a different color (for example, by encircling them with a red pen), you can prevent mistakes such as ``mistakingly connecting the outlet to 1.6 mm²'' during construction.

How to proceed with practical skills and take a breather

From here on, I will write in as much detail as possible the ``procedures'' and ``points of rest'' when creating published problem 13 by hand.

Step 1: Read the drawings and construction conditions (first resting point)

Take 5 minutes to thoroughly read the floor plan, single line diagram, and construction conditions on the question paper.
- Terminal block number and color specification (e.g. symbol 2 is white line)
- How to ground an outlet with a grounding terminal
- Where to use a ring sleeve, and where to use a plug-in connector (according to the explanation by Electrician Peko, A = ring and B = plug-in according to the construction conditions). (Hozan)

If you don't have a rough idea of the double-track diagram in your mind, you'll feel anxious about the rest of the work. On the other hand, if you read for 5 minutes properly, the second half will be much easier.

Take a deep breath and decide that today is the day to master this circuit before moving on.

Step 2: Draw a double line diagram

Draw from the white line (N)
- Power supply N → Terminal block No. 2 → Lamp white → Outlet N → Joint box
  First, draw the "white line network" as one route.
Draw a black line (L)
- Power supply L → Terminal block No. 1 → Internal switch → Terminal block No. 3 → Lamp black
- Power supply L → switch → outlet L (depending on the circuit configuration in question)
Draw a ground wire (E)
- Earth bus bar → Outlet ground terminal
- If there are any other devices that require grounding, summarize them (if there is an instruction in the question)

Once you have drawn this far, put down your pen and look around the terminal block and outlet. This is the "culmination point" of Publication Question 13.

Step 3: Dimensioning and cable cutting

Dimensions can be determined either by using a scale or by using an instrument as a ruler. The Gamidenki Channel introduces a method that involves ``aligning the center of the lamp with the center of the switch and cutting the length + 100mm of the start.''

Here, as an example,

Terminal block center to box center: 250mm
Launch: 100mm

If so, cut it out at 350mm. (Gamidenki channel)

Terminal block side: Exterior 5cm stripped, core wire 10mm
Box side: HOZAN's ``20mm all at once → separate later'' method is also effective, such as stripping 10cm of the exterior and removing 20mm (ring sleeve) or 12mm (insertion connector) of the core wire.

Once you've finished cutting this far, take a deep breath again.
Mistakes will be reduced if you decide that the wiring length is OK before entering the next wiring phase.

Step 4: Wiring the terminal block (substitute for automatic flasher)

Peel off the sheath on the terminal block side by 5cm and strip the core wire by 10mm (the same length is recommended for both HOZAN and Gamidenki).
Fine-tune the length of the core wire according to the size of the screw on the terminal block so that it just fits into the screw. (Gamidenki channel)
Insert as specified in construction conditions:
- Terminal 1: Black wire (power side L)
- Terminal 2: 2 white wires (power supply side N + lamp N)
- Terminal 3: Black wire (lamp L side)
After inserting the wire, be sure to pull it gently to make sure it does not come loose.
The core wire exposure should be 5mm or less. Exposing more than 5mm may result in a defect, so if it is too long, cut it back.

Step 5: Wire the lamp receptacle and switch

Gamidenki Channel explains how to install the lamp with a black wire on the black terminal and a white wire on the other side. (Gamidenki channel)

Pass the VVF through the square hole in the lamp pedestal
Wrap the black wire around the black terminal and the white wire around the opposite terminal in a right-handed (clockwise) direction, and tighten with a screwdriver.
Similarly, for the switch, connect the black wire to the L terminal (power side) and the black wire for the switch feed to the other terminals.

HOZAN's explanation emphasizes that ``when tightening screws, press while turning with a screwdriver'' and ``make sure that the coating is not caught under the screw, and that the exterior is visible from the pedestal.'' (Hozan)

Step 6: Connecting the grounded outlet

Peel off the exterior of VVF2.0-2C to a specified length and strip the black and white wires.
Connect the black terminal to the non-grounded terminal and the white terminal to the grounded terminal according to the instructions on the outlet.
Connect the bare copper wire or green wire to the ground terminal, and connect it with the ground bus bar in the joint box and a ring sleeve (use a small sleeve, etc. according to the construction conditions).

The grounding is so important that if you forget it, it's an instant failure, so it's a good idea to always check out loud whether the grounding wire is plugged into the outlet and whether it's grouped with other grounding wires at the joint.

Step 7: Joint processing (crimping point of passed multi-tool)

Where to use the plug-in connector
- Used for parts where multiple lines are grouped together, such as when white lines merge
- Strip the core wire by about 12mm and insert it securely as far as it will go (make sure it doesn't come out).
Where to use ring sleeves
- Confluence of black wires, confluence of ground wires, etc.
- Strip the core wire by 20mm, insert it into the ring sleeve, and crimp it using a qualified multi-tool according to the marking position (check the small/medium designation in the construction conditions).

After crimping,

Can you pull the line at the base of the sleeve and pull it out?
Is the sleeve positioned so that it fits inside the insulating tape?

Check. Once you create a small break by saying, ``I've completed this much for today,'' you can concentrate on the final review.

Items to check for defects and oversights (particularly dangerous points in Publication Question 13)

Finally, I will summarize the flaws and oversights that are particularly common in question 13. Please use it as is as a checklist for finishing checks.

Wrong number/color of automatic flasher (terminal block)
- Is the black wire coming to terminal 1?
- Are there two white wires in terminal 2 (power supply N and load N)?
- Is the black wire on the lamp side connected to terminal 3?
  → If even one wire is different, it is confirmed that it is malfunctioning = defective (refer to the HOZAN explanation/Gami Denki explanatory diagram).
Excessive core wire exposure (over 5mm)
- Is the core wire not exposed by more than 5 mm at any terminal block, lamp, switch, or outlet?
- According to Gami Denki's verification, there is no problem if the exposure is 2 to 3 mm, but if it exceeds 5 mm, there is a possibility of a defect.
The exterior is not visible from the pedestal
- For lamp pedestals and outlet pedestals, can the exterior be seen from above the pedestal?
- If the exterior is not visible from the bottom and the core wire coating is completely visible, there is a high possibility that it will be defective (HOZAN lamp receptacle explanation). (Hozan)
Forgetting to ground the outlet with a grounding terminal
- Is the ground wire connected to the ground terminal on the outlet side?
- Is it bundled with other ground wires in the joint box?
Cable size mix-up
- Are you using VVF1.6 for the outlet (if 2.0 is explicitly specified in the problem)?
- Isn't 2.0 too close to the terminal block or lamp side, making it difficult to fit?
Engraving error on ring sleeve
- Even though it is a small sleeve, is it crimped at the "medium" stamped position?
- Is the size of the sleeve appropriate for the number of pieces required (this is also emphasized in the crimping part of Denkiya Peko)? (Hozan)
Forgetting to use the mounting frame/wrong orientation
- Is the mounting frame properly used for the specified number of appliances? (Hozan's explanation introduces a trick: ``In this problem, it can only be used for three appliances, so mark it with a circle.'') (Hozan)
- Is the orientation correct (screw holes facing up)?
Inconsistency in overall continuity image
- Power supply → automatic flasher → L side of lamp
- Power supply N → Lamp N & Outlet N
- Power supply L → switch → outlet L (depending on circuit configuration)
  Trace it again in your head and check to see if the line is broken somewhere and if there are any extra lines.

Conclusion: How to use this article and reference materials

Published problem 13 is packed with themes that are very relevant to practical work, such as "automatic flashers (terminal blocks)" and "outlets with grounding terminals."

When reading this article,

First, try drawing only the double-line diagram.
While reading this article, practice only measuring dimensions and connecting terminal blocks and outlets.
Try going through it while timing yourself.

Try practicing with these 3 steps.

Actual electrical work on a building must be performed by a qualified person according to the Electrician Law. Please note that this article is only intended as a "practice circuit for the exam".