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RCD Test Function
Caution
Although fully protected against over voltage to 440V this tester should only be used on a
230V supply
The KT63DL will test all of the most commonly encountered standard and selective type AC
and type A RCDs.
Test requirements
Each RCD is tested to ensure that:
i.
It is not prone to ‘nuisance’ tripping and does not trip when a fault of half its rated current
is introduced. This is referred to as the x½ test.
ii.
It operates with a maximum disconnection time of 300ms (AC/A type) when a fault at its
rated current is introduced. This is referred to as the x1 test.
iii.
In the case of an RCD rated at 30mA there is an additional requirement that it operates
with a maximum disconnection time of 40ms when a fault of five times its rated current
is introduced. This is referred to as the x5 test.
For the reasons explained below all of the above tests have to be conducted at both 0° and
180° this means that four tests (or for 30mA RCD’s six tests) have to made for each RCD.
NB: The BS7671 2018 states that effectiveness is demed to have been verified where an
RCD meeting the requirements of Reg. 415.1.1 disconnector within 40ms when tested at a
current equal or higher than five times its rated residual operating current.
Automatic test
For the most commonly encountered type AC/A 30mA RCD the test process is even simpler.
Just turn the rotary selector to the ‘30mA AUTO’ setting select the RCD type required and the
KT63DL will conduct all six required tests at the single touch of a button.
Pass or Fail result
In addition to displaying the time taken for the RCD to trip the KT63DL will also indicate
whether it has passed or failed the test requirements of the BS7671.
