Porcelain cutouts of this design (having cemented-in/potted metal sections for the fuse and rear bracket) came about in the early 1980s. They were an el-cheapo design that evolved from sturdier (and more expensive) designs from earlier decades. These are a lineworker's nightmare since these widow-makers have been known to weather crack and otherwise have failures around where the porcelain meets up with the metal and potting material. Many of these cutouts have broken apart unexpectedly upon a lineworker either pulling the fuseholder door or replacing it with the live parts without notice (!) breaking loose! Some of these cracked more than others; many had beneath-the-surface fissures that were hardly visible. Owing to the fact there was at least one fatality due to these ticking time bombs, one company that made them paid big $$$ to cover the costs of utility group replacements with the familiar polymer types.

Of interest, the older open cutouts that employed a clamp-on bracket holder fuseholder assemblies were the absolutely best! Unfortunately cost-cutting among the manufacturers unveiled cheaper-made units such as the example shown. Photo found online.