G10 vs FR-4 Epoxy Fiberglass: What Procurement Should Know

G10 and FR-4 are the same epoxy glass laminate family; FR-4 simply adds a brominated, flame-retardant epoxy that meets UL 94 V-0. Mechanically and electrically they are close.

Procurement should specify FR-4 when the part must self-extinguish, which is most switchgear and busbar duty. Specify G10 when flame class is not required and you want the base grade.

Both machine the same, so the change is a material call, not a redesign. We stock and machine either grade to drawing.