You can do the work. The spec requires an engineer.

Somewhere around page forty of the spec there's a line about design by a licensed professional engineer. You find it Tuesday afternoon. The bid is due Thursday morning and you don't have an engineer to call. You could put a number in and leave that part out and hope nobody reads that far, but you've probably watched somebody try that, and you know how it goes when the owner's rep finally does.

So you let it go and move on to the next one. It doesn't feel like much at the time, because it's one job. It's never one job, though. It's a hospital in the spring, a water plant that fall, a school district the year after, and none of them feel connected to each other while they're happening. Then one day somebody asks why you don't do healthcare work anymore and you realize you can't point to the moment you stopped.

Your crew put the equipment in the way the drawings called for. The inspector signed off, the job closed, everybody shook hands. Then a month or two later your phone rings, the main is tripping on a load that shouldn't come close to it, and the person on the other end wants to know what your guys did.

Most of the time your guys didn't do anything. Breakers and relays arrive from the factory with generic settings already loaded, and somebody has to sit down with the actual system and work out what those settings ought to be for this building, this load, this service. On a lot of jobs nobody was ever hired to do that. That's a rough thing to explain to a client who is already annoyed, especially when the honest answer is that the work was never in anybody's contract. You end up defending an install that was fine.