What are the regulatory requirements by law for explosion protected
electrical equipment in Taiwan?

According to the Article 7 of “Occupational Safety and Health Act”, all explosion-protected (Ex) electrical equipment (for all Zones) shall comply with applicable safety standards specified by Ministry of Labor and complete the product safety information registration on the official web system (tsmark.osha.gov.tw). The Safety Label (so –called “TS Mark”) shall be marked/affixed on the Ex electrical equipment indicating compliance to regulatory requirement for legal manufacturing, import, lease, supply and installation. ITRI Type Verification Certificates for Ex electrical equipment indicate conformity to the specified safety standards, and are the satisfactory proofs for product safety information registration as described above.

What standards shall Ex electrical equipment comply with in Taiwan?

The Article 110 and 111 in “Safety Standard of Machinery, Equipment and Tools” specify that Ex electrical equipment in construction, performance, testing, marking and hazardous area classification shall comply with the Taiwanese National Standard CNS 3376 series (or IEC 60079 series), CNS 15591 series (IEC 61241 series) or other relevant standards additionally designated by Ministry of Labor. Due to the variations in technical requirement within CNS standard series that might not be suitably applicable, current valid IEC standards, whether the latest base editions or one base editions prior may take precedence if the CNS standard counterparts are not applicable or available.

As for Article 110 and 111 in “Safety Standard of Machinery and Equipment”,
Has Ministry of Labor announced adoption of any relevant (institutional or regional) standards other than CNS or IEC standards?

No. Currently, Ministry of Labor has not announced acceptance of any relevant standards other than CNS or IEC standards for Ex electrical equipment in Taiwan. For example, EN 60079 standards for ATEX or other national/regional standards (whether harmonized to IEC standards or not) are invalid and ineffective in Taiwan.