The 5 most common mistakes in panel assembly

Most panels that come in for repair don't have a component problem — they have an assembly-quality problem. Over the years we've collected the five mistakes we run into most often on site, and how to avoid them.

No labeling, no panel

An unlabeled panel isn't a problem while it's running — the problem starts at the first fault. Tracing where a wire goes takes hours, and an urgent repair gets delayed. Every wire, every terminal, every breaker should be labeled with its schematic number.

Sizing and heat calculations

The second most common mistake is picking cable cross-section "by eye" and skipping the internal heat calculation for the panel. In summer, in a cabinet heating up to 45°C, a drive ends up running at half its rated capacity. The calculation has to happen before assembly, not after.

A good panel shows itself the moment it's opened: it matches the schematic, everything is legible, and nothing needs to be traced by hand.

Practical tips

• Require every terminal and wire to be labeled with its schematic number.
• Account for the panel's internal heat calculation and ventilation at the design stage.
• Ask for a load-tested protocol at handover — a visual inspection isn't enough.