RCD test checker

Use this page after an RCD, RCBO or safety switch test has already been taken and one line of the record needs a disciplined check. The practical problem is not usually the multiplication. The problem is whether the row says enough for another competent person to see what was tested, which criterion was used and what still needs follow-up.

The calculator compares one row at a time. That is deliberate. RCD records become weak when a half-current no-trip check, a timed current-injection check and a push-button function check are collapsed into a single note such as "RCD OK". A useful row identifies the device, the test row, the selected or manually entered criterion, the observed outcome and the measured time where a timed row applies. This page turns those values into a consistent worksheet result without claiming that the device, circuit or installation has been fully verified.

The safest way to use the page is to treat the output as a record-checking aid beside the original instrument result, switchboard schedule, asset register or commissioning sheet. It helps expose missing values and marginal timing, but it does not decide the legal test interval, installation compliance, product suitability or final defect action.

Field use cases

Use the checker when the result already exists and the next job is to make the record usable. It suits electricians checking a test sheet before it leaves site, contractors preparing a handover set, estimators pricing a maintenance allowance, supervisors checking apprentice records and facility teams comparing current and previous register rows.

The calculator is not a schedule builder. It does not decide how often a workplace item must be tested, which devices must be installed, whether an installation is compliant, or whether a device should be replaced. It gives a clean reading of one row so the record can be discussed without ambiguity.

Recording one row

Start from the record in front of you, not from the result you hope to see. For a current-injection row, record the device label, rated residual current, selected row, observed trip or no-trip outcome, measured trip time where a trip is recorded, and the source of the comparison basis. For a push-button row, keep it as a function check. Do not convert it into a timed trip record.

Test row interpretation matrix

The selected row changes what a good record needs to contain. A non-operating-current row is a no-trip check for the entered duration. A rated-current row needs a time basis. A five-times row should state the entered maximum used for that row. A push-button row records the inbuilt test facility only and should not be treated as a timed current-injection result.

This separation matters in real records. If a push-button result is filed as though it were a timed current-injection test, a future reviewer may assume a measurement exists when it does not. If a non-operating row is recorded as simply "no trip" without the duration and device label, the entry is hard to compare at the next inspection.

Choosing the entered criterion

The calculator only compares against the criterion entered or selected by the user. That is intentional. It avoids hiding a legal or product requirement inside the tool. Before using a preset or manual value, identify why that value belongs to the row: current standard, workplace procedure, project specification, equipment manual, regulator guidance or a competent-person instruction.

Use a preset only when it matches the row being checked. Use the manual maximum where the record, procedure or manufacturer data calls for a different timed-row basis. For a five-times row, the calculator expects a manual maximum because this page does not supply a universal hidden threshold. For a non-operating-current row, the important entered value is the duration of the no-trip check, not a trip-time maximum.

Record wording matrix

A row can look acceptable arithmetically and still be weak as a record. The useful output is a line another competent person can trace back to the same device, row and basis.

Interpreting margin and utilisation

Margin and utilisation are record-review values, not a final decision about the device or installation. A positive margin says the timed value is below the entered maximum for that row. A negative margin says the measured time is above the entered maximum. A small margin still deserves attention when the basis, test point or device condition is uncertain.

Do not soften a late row because the device "still tripped". Marginal or late timing can point to a wrong criterion, transcription error, test point issue, device condition, connected load effect or method problem that needs follow-up.

Worked record examples

These examples use the same row types as the calculator body. The useful comparison is the calculator status plus the action that should remain with the job record.

If a row is flagged, do not change the row type or criterion until the status looks better. First confirm whether the original record, the test setup or the device itself needs correction.

Retest or investigate

Do not solve a flagged row by changing the inputs until the status looks better. Keep the calculator record aligned with the measurement in front of the user. If the record is wrong, correct the record or retest. If the result repeats, investigate the device, test point, circuit state, connected loads, instrument setup and applicable procedure.

This distinction keeps the worksheet from becoming a substitute for professional judgement. It also helps the exported row say something useful. Repeated no trip on timed row, device and setup to be investigated is clearer than a bare status.

RCBO record boundary

For RCBOs, keep the same residual-current test-row language but make the device reference specific enough to identify the RCBO, circuit and board. The overcurrent side of the RCBO, prospective fault current, loop impedance and cable withstand are separate protection questions handled by other checks.

Using the export in a job pack

The PDF export should be treated as a working record, not the original evidence by itself. Keep the original instrument record, the board or circuit schedule, the device label and any site procedure with it. The calculator output is useful when it gives the supervisor or future maintainer a compact summary of what was entered and why the row was flagged or kept for the job file.

For a clean timed row, identify the board, device, test point and criterion basis. For a flagged row, write the action still open. Do not use the export as final verification; it compares one recorded row with the basis entered by the user.

If the RCD or RCBO row raises a wider protection concern, move to the specific calculation rather than overloading this page. Use fault-loop impedance for loop-current context, short-circuit current for prospective fault-current context, and I2t cable withstand for conductor withstand against entered fault energy.

Source basis and Australian boundary

Australian RCD and RCBO testing records sit inside a wider verification and workplace-safety context. Public Australian guidance commonly distinguishes push-button checks from other testing records, and public guidance for some contexts describes no-trip and trip-time rows such as half-current non-operating checks, rated-current checks and Type 1 or Type 2 timing examples. This calculator uses those public concepts only as worksheet context.

The controlled requirements still belong to the current standards, regulator guidance, workplace procedure, manufacturer instructions and the competent person responsible for the work. AS/NZS 3760, AS/NZS 3000 and AS/NZS 3017 are mentioned as context because they are part of the Australian testing and verification environment. This page does not reproduce controlled tables and does not claim that the preset values are universal for every device or site.

Local authority, DNSP and site requirements can also matter. They may affect the test environment, documentation required before energisation or handover, acceptable evidence for a workplace record, and escalation path for a failed result. Treat those requirements as outside the calculator and attach the relevant basis to the job record where it affects the row.

Manufacturer instructions can override a generic worksheet assumption as well. Device type, electronic RCD behaviour, test button operation, line/load connection requirements, nuisance-trip history and replacement instructions should be checked from the product documentation or a competent person before relying on the row.

Stop points

• The device reference cannot be matched to the board schedule, circuit list, asset register or test sheet.
• The row type is uncertain or the criterion basis is not known.
• The measured value is missing from a timed row that should have a measured time.
• The test point, supply condition, connected load state or instrument setup cannot be confirmed.
• A non-operating row trips, a timed row records no trip, a timed row exceeds the entered basis, or a push-button check fails.
• Manufacturer instructions, workplace procedure or local requirements specify a different basis from the value entered here.
• The calculator output is being used as a compliance certificate, replacement test record or device replacement decision.