Updated Guidance on
RCCB Testing

Product Compliance and Safety


The new range of Hager Type A RCCBs conform to BS EN 61008-1 Amended 2017.  This standard recognises RCCBs not exceeding 30 mA as providing additional protection against electric shock.


Table 1 of BS EN 61008-1 specifies the manufacturer’s option of a maximum break time (commonly referred to as tripping) for a 30 mA RCCB as 40 ms at a test current of 250 mA.  This is aligned to IEC TS 60479 which relates to the effects of electric current on humans and which recognises 250 mA disconnecting within 40 ms.  This was reflected in the 18th edition BS 7671 in the note under 643.8 which states:


Effectiveness is deemed to have been verified where an RCD meeting the requirements of Regulation 415.1.1 disconnects within 40 ms when tested at a current equal to or higher than five times its rated residual operating current.


Unfortunately, the acceptable test parameter of a maximum trip time of 40 ms at  250 mA  has not yet been transferred to industry guidance  which still describes a single test option i.e. disconnect within 40 ms at 5IΔn and is therefore still the recognised practice in the UK.


Test Readings

The product standard BS EN 61008-1 allows the manufacturer to select characteristics of 5xI∆n or 0.25 A / 250 mA. The Hager RCCB is set to 0.25 A / 250 mA which allows conformity to both the product standard and BS 7671.


Test Procedure

Market feedback indicates that there may be a general issue around how to correctly test 30 mA RCCBs set to 0.25 A.


Regulation 643.8 requires the verification to be made by visual inspection and testing.  The test could be carried out using either the ‘Auto’ function of the installation test meter or manually selecting each test in turn.  We recommend the RCCB test is carried out in ‘manual mode’.  The test should be carried out at the device itself with all loads disconnected, as described in IET Guidance Note 3 and IET On-Site-Guide. 


The test equipment should be selected to the type of RCCB corresponding to the type of RCCB within the installation.


Should you wish to carry out a test at 250mA, where the required disconnection time is within 40 ms, a variable RCCB test instrument can be set to 50 mA and tested at X5, which is in effect carrying out the test at 250 mA, as permitted by the note under Regulation 643.8.


Also should your particular test instrument not have a variable facility then it is acceptable to carry out the test at a higher value of 300mA (set machine to 300mA and x1) to achieve a time within 40ms.


The 1x test is no longer a requirement but could of course be carried out.  The accepted requirements for this test are for disconnection within 300 ms as stated within IET Guidance Note 3 and IET On-Site-Guide.


Further Support

We are fully committed to supporting our customers and should you require any further clarification or support please contact our Hager Technical Support line on 01952 675689.

Author: Paul Collins, Technical and Training Manager


More from the 18th Edition

Surge Protection

A transient overvoltage or surge is a short duration increase in voltage measured between two or more conductors. In short this means anything from microseconds (millionths of a second) to a few milliseconds (thousandths of a second) in duration.

Read more


Selection of RCD Types

RCD's exist in various different forms and react differently depending on the presence of DC components or different frequencies.

Read more


Overload Protection

Devices such as switches, RCCBs etc. in distribution boards and consumer units may have historically had their rated current determined after having taken diversity into account but without having considered overload protection of the devices.

Read more


BEAMA Guides

A collection of the latest guides relating to 18th Edition, Hager is proud to be a technical contributor to these guides which provide technical advice on a range of 18th Edition related topics.

Read more