Machine builders rarely outsource panel building because they cannot do it. They outsource it because it is the part of the machine that scales worst. These are the questions that decide whether it goes well.
Almost every machine builder we work with could build their own panels, and most of them did for years. What changes is not capability, it is arithmetic. Panel building is labour that scales in a straight line — twice the machines is twice the wiring hours — while the engineering that makes the machine worth buying does not scale that way at all. The panel shop is usually the first thing to run out of room, and the last thing anyone wants to talk about.
The first question is not about price. It is: what exactly are you handing over? A drawing set with a bill of materials is a build-to-print package and can move to a supplier in weeks. A panel that exists as a schematic, a wiring habit and one experienced person’s memory is not a package — it is a transfer project, and pretending otherwise is how the first batch comes back wrong. Being honest about which of the two you have predicts the first year better than any price list.
Then ask what happens to the drawing. If the supplier maintains their own copy, you now have two masters and a divergence problem that surfaces on the day a device goes obsolete. Our position is that the customer’s EPLAN model stays the master, changes go back into it, and the panel is always built from the current revision. Ask a prospective supplier where the truth lives. The answer describes what maintenance will feel like in year three.
Ask about the test, in detail. "Tested" can mean a continuity check by the person who wired it, or a documented point-to-point test against the schematic by someone who did not, with an insulation and functional test on top and a signed record per serial number. Those cost different amounts and buy very different nights. If your panels go into machines that get exported, the test record is also the only thing that will settle an argument at a customer site two years later.
Ask what a change costs and how fast it lands. Series panel work is not a one-off order; it is a relationship in which the product changes. What is the lead time on a new revision, what happens to material already picked, who carries the panels built to the old drawing that are still in stock. Before nomination that is a five-minute conversation. After the first change it is a negotiation.
And ask about capacity honestly, on both sides. A supplier who says yes to every volume is telling you what you want to hear. We would rather state the batch size and call-off pattern we can hold, and what it would take to go above it, than win a nomination we have to apologise for in month four. Outsourcing a panel build works when the supplier’s limit is visible. It fails when it is a surprise.
— GANI Manufacturing engineering team