Does an Optical Isolator that meets IEC 60747-5-5 as required under cl. G.12 of 62368-1 need to fulfill the creepage distance requirements along outer component surface acc. 5.4.3?
More specifically you asked: For use of optocouplers according to Clause G.12: If we are using an opto device with IEC 60747-5-5 approval present, with V(ini,a) value that is greater than the electric strength requirement as per 220.127.116.11, does the requirement still remain for a minimum external creepage distance to be present along the component body, or is compliance assumed due to complying with Clause G.12, thus allowing in application to use a reduced external creepage distance than Clause 5.4.3 would usually allow?
In response, per 5.5.4, for Optical Isolators used as a Safeguard (acc. to cl. 5.5), the Insulation of the component shall comply with the requirements of 5.4 or with cl. G.12.
When the Optical Isolator is used as Safeguard providing Supplementary or Reinforced Insulation acc. to cl. 18.104.22.168 and it meets G.12, such a component has no minimum internal Clearance or Creepage Distance, and no minimum distance through insulation requirement. However, as you stated, the referenced initial test voltage V(ini a) of the Optical Isolator must be least equal to the appropriate test voltage in 22.214.171.124.
The above requirements apply to the Insulation of such Optical Isolators related to internal spacings. However, the evaluation of the distances along the component outer surface in combination with the final end-product construction still applies. Therefore, specifically for Creepage Distances, appropriate external Creepage Distances acc. to 5.4.3 still apply.