UL773 sets four material performance requirements for photocell bases that PC cannot reliably satisfy in the real-world thermal and humidity

PC bases fail in photocell applications because outdoor photocell installation conditions are sustained at high temperatures at the luminaire top,

Photocell failures in high-temperature countries are not random. They follow predictable failure mechanisms tied to factors such as installation position,

Photocell base material may seem like a small detail, but it has a strong effect on product life.
PC

The base material matters more than it looks like it should.
Outdoor lighting is not gentle. Photocells get hot.

GF bases are stronger than PC bases in the areas that matter most for outdoor photocontrols. They handle heat better.

For a photocontrol manufacturer like Long-Join, UL773 should come first. It is the most direct standard for the photocell, photocontrol,

IP ratings measure dust and water ingress. Salt spray corrosion is a chemical process that IP testing was never designed

IP66D combines dust and water protection ratings but is not a comprehensive indicator of suitability for outdoor street lighting environments.

ENEC certification for photocontrols is not a simplified version of CE with extra paperwork. It is a comprehensive technical assessment