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Functional testing, and which devices have a test buttonWhich devices have no test button?
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Functional testing is done manually — you operate the thing and watch it work. Switches on and off; test buttons pressed. And the test buttons are not where people assume:
| Device | Test button? | How you check it |
|---|---|---|
| RCD | Yes | Press the test button |
| RCD socket outlet | Yes | Press the test button |
| RCBO | Yes | Press the test button — often small, and marked T |
| AFDD | Yes | Press the test button — and read its indicator to the maker’s instructions |
| SPD | No | The window: green good, red replace |
Do not walk past the RCBO's button. It is doing the work of both a breaker and an RCD, and its test button is often small and tucked away — easy to miss. The SPD is the odd one out: no button at all.
✋Green or red, on an SPD. The status window is the check. Red means it has reached the end of its life (its internal disconnector has operated), so it is replaced. An AFDD is different: test it with its test button and read its indicator to the maker’s instructions.
AFDDs usually are not separate units. For most circuits the arc fault detection is incorporated with a circuit breaker or an RCBO, so you are not buying a standalone device. And it is surge protective device, not surge protection device.
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- Building Regs
- PAT
- Fundamental Inspection & Testing
- Initial Verification
- Periodic Inspection & Testing