Safety Laws for Electrical Work

Article 1 of the Electricians Act says its purpose is to set the qualifications and duties of people engaged in electrical work, and so help prevent disasters caused by defective electrical work. Regulating the manufacture and sale of appliances is the purpose of the Electrical Appliances and Materials Safety Act (電気用品安全法). Registering contractors and making their business proper is the purpose of the Electrical Contractors Act (電気工事業法). Regulating the construction, maintenance and operation of electrical facilities belongs to the Electricity Business Act (電気事業法).

A second-class electrician may work on general electrical facilities etc. (一般用電気工作物等), which include general electrical facilities and small business-use electrical facilities (小規模事業用電気工作物). A 20 kW solar system is a small business-use facility, so it is within the second-class scope. A 300 kW factory is a private-use electrical facility (自家用電気工作物) under the Act, which needs a first-class electrician (or a certified electrical worker (認定電気工事従事者) for parts used at 600 V or below). Neon work and emergency standby generator work are special electrical work (特殊電気工事) and need a special electrical work qualification (特種電気工事資格者).

Article 1 of the Order treats wiring on the secondary side of a small transformer for a bell or intercom (secondary voltage 36 V or less) as minor work. 24 V is 36 V or less, so no licence is needed. Putting wires into conduit, attaching wiring devices to building materials (except replacing exposed switches or outlets), and burying an earth electrode and connecting the earthing wire are all listed in Article 2 of the Enforcement Regulations as work that only an electrician may do.

Article 2 of the Enforcement Regulations lists fixing a metal box to a building material as work only an electrician may do. Replacing an exposed-type switch or outlet is excluded from the work that needs a licence. Installing an electricity meter used at 600 V or below is minor work (軽微な工事) under Article 1 of the Order. Assisting work done by an electrician is minor work (軽微な作業) under Article 2 of the Regulations.

Simple electrical work is work on private-use electrical facilities under the Electricians Act (such as demand facilities under 500 kW) that are used at 600 V or below, excluding power lines (Article 2-3 of the Enforcement Regulations). Work on high-voltage receiving equipment belongs to a first-class electrician. Emergency standby generator work is special electrical work and needs a special electrical work qualification. Demand facilities of 500 kW or more are outside the private-use facilities covered by the Electricians Act, so the work is not simple electrical work either.

Special electrical work (特殊電気工事) means two kinds of work: neon work and emergency standby generator work (Article 2-2 of the Enforcement Regulations). Even a first-class electrician cannot do them without a special qualification certificate for that kind of work. Replacing a house's distribution board is work on a general electrical facility, which first- and second-class electricians may do. Lighting used at 600 V or below in a private-use facility is simple electrical work, which a first-class electrician or a certified electrical worker may do. An 8 kW solar system is a general electrical facility, which a second-class electrician may do.

Article 5 of the Electricians Act requires an electrician to do the work so that it meets the technical standards, and to carry the licence while working. The periodic training course within every 5 years is a duty of first-class electricians (Article 4-3), not second-class ones. There is no duty to report each job to the governor. The licence does not show your address, so a change of address does not require rewriting it.

Under Article 5 of the Order for Enforcement of the Electricians Act, when an item on the licence (such as the name) changes, you apply for rewriting to the governor of the prefecture that issued the licence, not the governor where you now live. Licences are issued by prefectural governors, so the Minister of Economy, Trade and Industry is not where you apply. The Electrical Engineers Examination Center (電気技術者試験センター) runs the examination; it does not handle licence procedures.

Under Article 4(3) of the Order for Enforcement of the Electricians Act, a person who lost a licence, got it reissued, and then finds the lost one must submit it without delay to the prefectural governor who reissued it. You cannot keep using both, and destroying it yourself is not enough. It goes to the governor who reissued it, not to the Minister.

Under Article 9 of the Electricians Act, the prefectural governor may, to the extent needed to enforce the Act, require electricians, special electrical work qualification holders and certified electrical workers to report on their electrical work. The Minister and the mayor are not the parties named in this article. The power line operator investigates general electrical facilities under the Electricity Business Act (電気事業法); it does not collect reports from electricians.

Under Article 2 of the Ordinance, low voltage is 750 V or less for DC and 600 V or less for AC. Voltages of 300 V or less are low voltage too, but 300 V is not the upper limit. 750 V or less is the low-voltage range for DC. 7,000 V is the upper limit of high voltage: for AC, over 600 V up to 7,000 V is high voltage.

For DC, 750 V or less is low voltage, so DC 700 V is low voltage. AC 400 V is 600 V or less, so it is low voltage, not high voltage. AC 6,600 V is over 600 V and up to 7,000 V, so it is high voltage. DC 10,000 V is over 7,000 V, so it is extra-high voltage.

General electrical facilities are equipment that receives power at 600 V or below and uses it on the same premises, plus small generators. A solar system under 10 kW is general, so a 5 kW solar system and the house wiring are general electrical facilities. A factory that receives high voltage is a private-use electrical facility (自家用電気工作物). A 30 kW solar system is 10 kW or more and under 50 kW, so it is a small business-use electrical facility (小規模事業用電気工作物). Sites that manufacture explosives are excluded from general electrical facilities by Article 48 of the Enforcement Regulations.

No wind power system counts as a general electrical facility (the limit in Article 48(4) of the Enforcement Regulations is 0 kW), and small wind generators under 20 kW are small business-use electrical facilities. So a 3 kW wind system is small business-use. An 8 kW solar system (under 10 kW) and a 5 kW fuel cell (under 10 kW) are general electrical facilities. A 60 kW solar system is 50 kW or more, so it is not a small generator and not a small business-use facility.

Under Article 57 of the Electricity Business Act, the person who maintains and operates the power line directly connected to the general electrical facility (the power line operator, 電線路維持運用者) does the investigation. Under Article 96 of the Enforcement Regulations, periodic checks are at least once every 4 years (at least once every 5 years for facilities whose inspection has been entrusted by the owner to a registered inspection contractor (登録点検業務受託法人)), and a check is also made when installation or alteration work is completed. Owners, electricians and governors have no such duty.

Under Article 57(2) of the Electricity Business Act, the power line operator must notify the owner or occupier without delay of the measures needed to meet the technical standards and of the consequences if those measures are not taken. The article does not provide for stopping the supply, for fines through a report to the Minister, or for ordering the electrician to make repairs.

Private-use electrical facilities under the Electricians Act are demand facilities under 500 kW and similar, and work on them belongs to first-class electricians (certified electrical workers may also work on parts used at 600 V or below). High-voltage receiving equipment in a 400 kW building is such a facility. An ordinary house and a 20 kW solar system (small business-use) are general electrical facilities etc., which second-class electricians may also work on. Demand facilities of 500 kW or more are excluded from the Act's private-use facilities, so the Act's licences do not cover them.

Under Article 3 of the Electrical Contractors Act (電気工事業法), a business with offices in two or more prefectures registers with the Minister of Economy, Trade and Industry. A business with offices in only one prefecture registers with that prefecture's governor. It does not register only with the governor of the head office's prefecture, or with both governors. Mayors are not registration authorities.

Under Article 19 of the Electrical Contractors Act, a chief electrician must be a first-class electrician, or a second-class electrician with at least 3 years of electrical work experience after the licence was issued. One year of experience is not enough. A certified electrical worker does not meet the requirement. A person with no licence cannot be appointed, however long their experience.

Under Article 24 of the Act and Article 11 of its Enforcement Regulations, an office doing only general electrical work must keep an insulation resistance tester, an earth resistance tester, and a multimeter that can measure resistance and AC voltage. A high-voltage detector, a protective relay tester and a dielectric withstand tester are extra instruments for offices that also do private-use electrical work. A clamp meter and a phase rotation tester are not among the instruments the regulation requires.

Under Article 26 of the Electrical Contractors Act, a book is kept at each office, and under Article 13 of the Enforcement Regulations it is kept for 5 years from the date of entry. The entries include the client's name and address, the type and site of the work, the date, the names of the chief electrician and the workers, the wiring diagram, and the inspection results. One book at the head office, 3 years, and leaving out diagrams and results all differ from the rules.

Under Article 25 of the Electrical Contractors Act, the sign is displayed in an easily visible place at each office and at each site of electrical work. Under Article 12 of the Enforcement Regulations, sites where the electrical work is completed in one day are excluded. Head office only, work sites only, and the representative's home all differ from the rules.

In METI's list of covered items, cables with a conductor cross-section of 22 mm² or less, 7 cores or fewer, and a rubber or synthetic-resin sheath are specified electrical appliances. A 2.0 mm diameter conductor has a cross-section of about 3.1 mm², so this VVF cable (600 V PVC-insulated PVC-sheathed flat cable) qualifies. Synthetic-resin flexible conduit, ventilation fans (rated 300 W or less) and LED lighting fixtures are non-specified electrical appliances.

Under Article 28 of the Act, electricians and others must not use electrical appliances in installing or altering electrical facilities unless they bear the mark in Article 10(1). This use restriction exists separately from the sales restriction (Article 27). Self-made fittings without the mark may not be used. Specified appliances also may not be used unless they bear the mark.

Under Article 17 of the Enforcement Regulations, the marking of a specified appliance consists of the symbol (PSE in a diamond), the name of the notified business operator, and the name of the registered inspection body that issued the conformity certificate. A non-specified appliance shows the symbol (PSE in a circle) and the operator's name; the inspection body's name is not required. The operator's name and the PSE symbol are needed for both. The name of the shop is not part of the marking.