Safety Standards of Photocouplers

When mounted in electrical equipment as a means of isolation to protect the human body from electric shock, photocouplers may be subject to various regulations in terms of safety standards.

Various regulations and standards for ensuring safety exist.

From the perspectives of design and manufacturing, safety standards can be categorized into "set standards" and "parts standards".

Set standards are the basis for designing and manufacturing equipment such as TVs, VTRs, and power source units. “Set standards” differ according to equipment type, isolation method and its class, driving voltage, etc.

Also, the items (dielectric strength (isolation voltage), creepage distance, clearance, etc.) that must be maintained at the insulation portion are specified as “Parts standards".

Major safety standards

Parts standards
UL1577 (cUL)
Standard for isolation voltage (1 min)
Approval organization: UL (Underwriters Laboratories Inc.) 
EN60747-5-5
Standard for maximum operating isolation voltage and maximum overvoltage
Approval organization: VDE (Verband Deutscher Elektrotechniker)

Approval organization: TUV (Technischer Uberwachungs Verein)
Set standards

(Approval organization: BSI (UK), SEMKO (Sweden), etc.)

EN60950
Standard for telecommunication network equipment (workstation, PC, printer, fax resistor, modem, etc.)

EN60065
Standard of home appliance equipment. (TV, radio, VTR, etc.)

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