There are several restrictions on the import and use of electrical equipment in Japan. Like most other advanced countries, Japan has its own standards. Equipment being installed in building must be certified for use in Japan. JIS is one of the more common standards applied in Japan. It is very similar to UL, but UL approval is not recognised in Japan. You must get Japanese approval.
Having UL or IEEE certification is of no value in Japan. You will need to get your equipment tested by an approved laboratory in Japan. JETRO in your country will be able to assist you with more information on this very complex topic.
What happens if equipment that is not approved is installed in a building? First you will have to find a contractor crazy enough to accept such a task. All reputed Electrical contractors will flatly refuse to touch unapproved equipment. In the event there is a malfunction that causes and accident of any level, your insurance policy may be voided due to the installation of unapproved equipment.
If the malfunction causes a fire or an injury, the Ministry of Labour, the Police and several other departments will close down the Building till their investigation is over. If they find unapproved equipment, the installer would be fined and they would face several weeks of work suspension for the whole company. If a person is injured, a charge of Professional negligence could be levied against the installer and the building owner.
Getting electrical equipment approved for Japan is a long and onerous process. The end user would not be willing to go through the cost and time to have this done. The manufacturer or their local agent in Japan would be the only ones who could get the equipment approved.
Having a Sales Agent in Japan is important. Most end users want to see a full set of spares stocked in Japan and service to the building within 4 hours of the incident.
If your equipment has no track record in Japan, your best approach would be to work with the Electrical Contractor to have your equipment added to the Approved Maker List that is usually issued with the RFP.