A curable epoxy resin composition comprising (a) cycloaliphatic diglycidyl compound as epoxy resin, and (b) an antioxidant (b1) alone or a combination of an antioxidant (b1) and an UV absorber (b2), characterized in that the antioxidant is a compound of the general formula I ##STR00001## wherein R.sub.1.dbd.--H, --OH, --O--C.sub.1-C.sub.18-alkyl, --C.sub.1-C.sub.18-alkyl, --C.sub.5-C.sub.12-cycloalkyl being unsubstituted or being substituted with C.sub.1-C.sub.6-alkyl or C.sub.1-C.sub.6-alkoxy, or --CH.sub.2--C.sub.5-C.sub.12-cycloalkyl being unsubstituted or being substituted with C.sub.1-C.sub.6-alkyl or C.sub.1-C.sub.6-alkoxy;R.sub.2,3,4,5=independent from each other --C.sub.1-C.sub.6-alkyl; and R.sub.6=a bivalent aliphatic, cycloaliphatic or aromatic residue, andwherein the weight ratio between the components (a) and (b) is from 90.0:10.0 to 98.5:1.5,with the proviso that the weight portion of the component (b1) is at least 0.5,having a very good weather resistance after curing by polyaddition with a polycarboxylic acid anhydride or by homopolymerization and which is particularly suitable as electrical insulation material.