If you are going to rely on an engineering firm to reach bigger work, the most important question to ask them has nothing to do with price, portfolio, or turnaround time. It is whether they also do electrical contracting. That single fact decides whether the partnership is safe to build on or whether it carries a conflict you will be managing for as long as it lasts.
What to confirm, in order of weight
Does the firm do electrical contracting?
What it is. The structural question. A firm that only does engineering has no way to bid against you. A firm with a contracting arm always does, regardless of how it behaves in practice.
The trade-off. Plenty of firms will give you the reassuring answer, so confirm it structurally rather than verbally. Does the firm hold electrical contracting licenses? Does it self-perform installation work? Does it appear on projects as a contractor, or only as the engineer of record?
Is there a licensed PE who will stamp the work?
What it is. The credential that lets you bid the work in the first place.
The trade-off. This one is table stakes and easy to verify, which is why it gets checked first and weighted too heavily. A stamp tells you nothing about the conflict question or about how the firm behaves on a job.
Do their engineers visit the site?
What it is. Whether the engineering is done from drawings or from the actual conditions in the building.
The trade-off. Site visits cost hours and they catch the things drawings do not show. A firm that works only from documents will be cheaper on the proposal and more expensive on the project.
Do they stand behind the work when something goes wrong?
What it is. What happens at two in the morning when a setting is wrong and a client is waiting.
The trade-off. This is the hardest to verify in advance and the easiest to check with references. Ask specifically about a job that went badly, not about the ones that went well.
Why the first question outranks the rest
The whole value of an engineering partnership comes from depth, and depth requires you to share openly. The firm does its best work with full access to the RFP, the client, the site, and the details of the project. If you are holding things back to protect yourself, you get worse engineering and a weaker relationship.
A responsive, credentialed, accountable firm that also competes with you is still a firm that competes with you. The other three questions matter once the first one is settled, and not before.
Taking the conflict off the table is what lets the partnership become the growth engine it is supposed to be. You go after larger, engineering-required work without wondering whether your partner will turn up as a rival on your own client's next project. That confidence is what lets you commit to one firm, build real continuity, and grow into the work you have been shut out of.