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#193924 - 04/28/10 06:42 PM Failure rate of RCDs  
C-H  Offline
Member
Joined: Sep 2002
Posts: 1,497
Stockholm, Sweden
The Danish authorities have undertaken a large study of the realibility of RCDs in which hundreds of installations have been tested. From 2 to 10% of the units were found not to work as intended. Some passed the test button test, but failed to work when tested with proper equipment test. The failure rate was found to increase with age and brand name products were not immune to failure.

A comprehensive report in English is available at:

http://www.sik.dk/content/download/5099/71907/file/HPFI%20rapport%20-%20engelsk.pdf


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#193925 - 04/28/10 07:06 PM Re: Failure rate of RCDs [Re: C-H]  
Wolfgang  Offline
Member
Joined: Sep 2005
Posts: 153
the very West of Germany
The main problem, I see, is not a failure rate of 10% after 10 years, because we can easily check these devices (as electricians), but what about fuses or breakers. There are so many out there, aged 30 or 40 years, but nobody can tell whether they will trip at the correct overcurrent value after such a long time.


#193936 - 04/29/10 10:05 AM Re: Failure rate of RCDs [Re: Wolfgang]  
Texas_Ranger  Offline
Member
Joined: Dec 2001
Posts: 2,399
Vienna, Austria
I haven't seen to many failed RCDs so far, and most failed on the safe side - tripped and couldn't be reset any more. Only one or two refused to trip, on one even the test resistor blew up spectacularly.

Same goes for MCBs, but I did encounter one very old range (Schrack HLS, manufacturing date stamp 1960) that refused to trip as a whole. There were a few dead shorts (faulty light socket) but the MCBs (10A H curve) never tripped before the 20A gL main fuse blew.


#193941 - 04/30/10 02:20 AM Re: Failure rate of RCDs [Re: Texas_Ranger]  
frenchelectrican  Offline
Member
Joined: Feb 2003
Posts: 939
Wi/ Paris France { France for ...
I haven't run into too many RCD failure in France unless you got a Le Cheapie or butched work on the RCD unit.

Yeah we do test the RCD but with older units it pretty tricky to get set up to function properly.

But with nice hevey bolted fault circuit then it is good time to replace the RCD I have deal with that due once you reset it it will never function correct.

Merci,Marc


Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)



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