Every panel builder says their cabinets are tested. The difference between suppliers is not whether they test — it is whether the record they hand you would survive being checked.
A point-to-point test verifies that every conductor lands where the drawing says it lands. It is unglamorous, it takes real hours, and it is the cheapest defect-detection step in the entire project. A wiring error found on the bench costs minutes. The same error found during commissioning costs a crew, a scaffold and a day of somebody’s startup window.
What the record has to let someone do
The test is worth exactly as much as the record it produces. A useful record lets a person who was not there do three things: find any given terminal, see what was measured, and see who is accountable.
| Field | Why it is there |
|---|---|
| Cabinet and drawing reference | Ties the record to a revision, so a later drawing change is visible |
| From terminal and to terminal | The actual claim being made |
| Wire number | Lets someone find the conductor physically |
| Result | Continuity pass/fail — and the measured value where it matters |
| Date | Establishes what was true when, which matters after a rework |
| Tester | A name, not a company |
| Witness | Where the client witnesses, a second signature |
If a record has a tick per cabinet rather than a line per terminal, it is a statement of intent, not a test record.
What gets measured, not just checked
Continuity is the baseline. On most industrial cabinets three more measurements belong in the record because they catch different faults:
| Measurement | Catches |
|---|---|
| Insulation resistance | Damaged insulation, swarf across terminals, moisture ingress |
| Loop resistance on analogue circuits | Marginal terminations that pass continuity and fail under load |
| Earth continuity | Bonding that was assumed rather than made |
| Power-up and soak | Supply faults, fan failures and thermal problems that only appear warm |
The soak is the one most often skipped and the one that catches the most embarrassing failures. A cabinet that has run for a few hours at temperature has already survived the class of fault that otherwise turns up on day two of commissioning.
Rework changes the record
Every point that is reworked has to be retested and the record updated with a new date and signature. This sounds obvious and is routinely not done — the original record stays in the pack and the rework is remembered informally.
The failure this causes is specific: months later a loop misbehaves, someone consults the test record, sees a pass, and looks everywhere except the terminal that was changed. Keep superseded entries visible rather than overwritten, so the history is legible.
How it connects to the FAT
Point-to-point is not the factory acceptance test. It is what has to be finished before the FAT is worth running.
| Stage | Question it answers |
|---|---|
| Point-to-point test | Is the cabinet wired the way the drawing says? |
| Internal pre-FAT | Does the system work well enough to be witnessed? |
| Witnessed FAT | Does it meet the agreed protocol, with the client watching? |
| SAT | Did it survive shipping and installation? |
| Loop check | Does the field device move the number on the operator’s screen? |
Running a witnessed FAT before point-to-point is complete is a common way to waste a client’s travel budget. The visible symptoms — a channel that does not respond, a graphic that shows nothing — are wiring faults wearing a software costume, and everyone spends the morning debugging the wrong layer.
What to ask for in the tender
One line does most of the work: “Point-to-point test records shall be provided per cabinet, one line per terminal, signed and dated, referencing the issued loop drawing revision.” Suppliers who already work that way will not blink. Suppliers who do not will tell you, one way or another, in how they price it.
Related: engineering, FAT and commissioning, control cabinet manufacturing.
Ask for a sample test pack
We will send a redacted example of the records that ship with our cabinets so you can compare them against what you are being offered elsewhere.