Urgency writes the query. Somebody standing in a loft with a dead circuit types the shortest possible thing, so a page that answers before it introduces itself is the one that wins the detour.
A regulation change is a traffic event. When a requirement is updated, every electrician in the country searches at once for what it means in practice, and a wholesaler that published an explanation early captures all of it.
Specification questions bring both audiences. Professionals and confident householders enter cable sizes, breaker ratings and what a particular installation requires, and answering it establishes the shop as the knowledgeable one.
Account searches signal value. Somebody looking for trade terms and credit is planning to buy repeatedly, and that visitor is worth many people buying a single item.