• IMPORTANT: Please note that nobody on this forum should be seeking from or providing advice to those who are not competent and / or trained and qualified in their field (local laws permitting). There is a discussion thread on this global industry-wide matter HERE. This also has more information about the warning with regards to sharing electrical advice in some countries. By using this forum you do so in agreement to this.
  • If you have electrical work available, then you are in the correct forum.

    Post details of the position you have on offer in this forum. Domestic / homeowners are also welcome to post electrical work they have available on their property. Or you're welcome to seach for a Local Electrician in our directory.

Discuss RCBO trip test query - Testing wrong or is there a fault? in the Electrical Work Up For Grabs |Electrical Jobs area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

Reaction score
0
Hi,

Can anyone please explain why my friend's 30mA trip RCBOs passes the trip test (e.g. x5 is less than 40ms) when the test is done at the consumer unit but fails when the test is done at the sockets.

Is he doing something wrong or is there a fault somewhere (the RCBO or the circuit?

Thanking you in anticipation.
 
I beleave its the way the tester works to simulate the fault , if there is already leakage on the circuit, for example a fridge or computers , thats when the tester gives the false readings .
 
Yes, if there are other loads you might expect the rcd/rcbo to trip before its supposed to due to the cumulative effect, but there are also times when they won't trip at all when tested end of circuit.
 
I would suggest ramp testing the RCD

Had this problem a little while ago fitted a new consumer unit and everything tested ok, went back 6 months later to do some additional work and the RCD would not trip on the 1x test and the 5x result was a bit close to the limit when tested at a socket same tests at the CU gave satisfactory results although I was not too happy so decided to ramp test at the CU and the socket and both results were very similar with an indicated trip current of 35ma. The result after a phone call to the manufacturer was a replacement RCD in the post

I now always ramp test RCD's before any other tests and I have had quite a few that trip above the rated tripping current
 

Reply to RCBO trip test query - Testing wrong or is there a fault? in the Electrical Work Up For Grabs |Electrical Jobs area at ElectriciansForums.net

This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top