Guid­ance for Test­ing 
CD285U RCCB

Devices pro­duced up to July 2019

 ** Please note: This guid­ance DOES NOT ap­ply to CD285U RCCB with a pro­duc­tion date code after 19219 **

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