RCD चयन कैलकुलेटर

How this is calculated#

The tool says whether a circuit needs additional RCD protection. It picks the rated residual current. It can also test a measured trip time against the limits.

1. Need. The tool reads the installation and the circuit type. It decides whether Clause 2.6.3.3.1 of AS/NZS 3000:2018 asks for additional protection.
2. Rated current. It gives the rated residual current that the clause requires for that circuit.
3. Maximum for the duty. In New Zealand you pick the duty: shock, property, patient or children. The tool gives the highest rated residual current for that duty (Electricity (Safety) Regulations 2010 reg 24).
4. Trip limits. It gives the trip limit at the rated residual current. It also gives the limit at five times that current (reg 24).
5. Disconnection time. It gives the maximum disconnection time (Cl 5.7.2).
6. Measured result. If you enter two trip times, the tool compares them with the limits. It also gives the current below which the device must not trip.

Worked example#

• Socket‑outlets in a home, tested at 250 ms and 50 ms. The tool requires 30 mA protection. The limits are 300 ms at the rated current and 40 ms at five times it. The 50 ms reading exceeds 40 ms, so the test fails.

Limits#

• The tool does not choose a make or model. It does not check discrimination between RCDs.
• It does not test nuisance tripping from earth leakage. A circuit with high leakage needs a site test.
• The type of RCD (A, F or B) comes from the equipment on the circuit. See the learn page on RCD types.
• The tool reads AS/NZS 3000:2018. Check the regulations for later changes.
• Australia caps the circuit and New Zealand caps the socket‑outlet in some cases. Check the hint on the form.

See also: RCD types and where they are required, Testing to Section 8 and Wet area zones.