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Discuss Testing RCBO x5 times in the Electrical Forum area at ElectriciansForums.net

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Hello everyone,
Is it necessary to test RCBO x5? Some say that you can’t even test at x5 times because it can damage RCBO. Others that you can, but we don’t put the result in testing sheets. I found a recommendation that it is advisable to test x5.
I wouldn’t expect an rcbo to be damaged by a leakage test unless the current was in the Ka region not the mA region.
remember that the current normaly would be a multiple of the rcd trip current I.e. 30mA x 5 = 150mA or in technical terms the grand total of F-All current.
The concern was raised about the multiple switching on/off rather the level of current, which could reduce the lifetime of the device, if the whole range of tests were performed on AC and A settings. Hence the requirement to test only on AC and only the 1x test.

To answer the OP question - the wiring regulations BS7671 only require the 1x test to be performed on the setting for type AC. There's nothing to stop us from doing the 5x test for our own piece of mind though.
There seems to be many spurious reasons given for the change in RCD/RCBO testing, but I think the true reason was to make testing quicker & cheaper.

No, you will not damage a RCBO testing it at 5*In as @James points out that is something like 40,000 times smaller than the rated ultimate breaking capacity.

No, you will not wear it out either under any sane regime. Looking at a typical data sheet (ABB came up first in google) they often are rated for 10,000 electrical cycles (i.e. operating at rated load of tens of amps) or 20,000 mechanical cycles (operating with negligible load).

If your traditional test was two 'In' trips (0 deg/180 deg), two '5*In' trips, and a test-button trip, along with maybe initially isolating for other tests, that is 6 cycles. To wear it out you would need to do that 3,333 times. If you did that test on every working day in a year (around 200) it would take you 16 years.
Sausages (just for tracking a min lol needed a word, I must be hungry)

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