Ever hear "it's not what you say, but how you say it?" The principle applies here.
It's common for prints, etc., to somewhere have blanket statements such as 'or equivalent.' Think of those statements as acting like the first half of the NEC- just general statements that can / will be modified by the balance of the agreement.
The long text of the contract might say 'use Brand X.' That statement overrides / modifies the blanket 'or equivalent' that you might see elsewhere. This can get interesting when there are conflicting specs, or when the specified product does not exist. For example, when the job specs QO breakers in GE panels.
That's when you need to stop and get things cleared up, in writing, before you go any further. Don't kid yourself; I've seen plenty of 'respectable' folks deliberately fill their specs with contradictions simply to mess with the contractor. Let me give one example ...
A customer wanted some shelving installed. He provided drawings that showed each unit to have five shelves and a closed top - which was simply another shelf installed at the top. The specification referred repeatedly to 'five shelves,' so the contractor priced the job using five shelves. Once one site, the contractor saw that he needed six shelves to make each unit. Oops. Big money loser for the careless contractor - after all, the drawing clearly showed five shelves AND a closed top, even specified the shelf placement. I write that up to a simple mistake on the contractors' part, save for the fact that the customer gleefully explained to me how he had 'set up' the contractor to make that exact mistake. Pure malice on the customers' part.
