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Had a RCD fail the 180 deg test today. Works ok if I just do the 1x test, get 6.4 ms, on 5x get 25 ms but if I do the auto test on me megger it fails the 180deg 1x test. I'm presuming its U/S any thoughts guys thanks in advance.
 
The times one test reading is incredible, I get 20-40 usually depending on the RCD, and at times 5 8-20 usually, don't think Ive ever seen a times one at 6.4 myself, still we learn every day here on EF.
 
sounds dodgy. did you test at the RCD with no loads applied?
 
I tested four today...they were getting on a bit certainly > 10 years one failed on x1 the others all within regs,bin it, way I see it, it may not ever get tested again, or for at least 5/10 years ..sling the bugger
J
 
Sorry for late reply. I tested on the ring sockets tried it a few times, sorry I put the times down wrong they where the others way round. The 5x one was done manually as the auto test failed to go past the 1x test on 180deg. Iv never had this fault before ha rcd's fail but not work on 0deg and fail on 180deg. Going to try my meter in the morning at home just to make sure it's not that.
 
Sorry for late reply. I tested on the ring sockets tried it a few times, sorry I put the times down wrong they where the others way round. The 5x one was done manually as the auto test failed to go past the 1x test on 180deg. Iv never had this fault before ha rcd's fail but not work on 0deg and fail on 180deg. Going to try my meter in the morning at home just to make sure it's not that.

For accurate RCD test results, always test RCD's at the disconnected load terminals of the device at the CU... Your testing the RCD device not the circuit it's protecting...
 
He's quite right of course if you want to follow the testing regime to the letter, personally I see nowt wrong with putting the plug top tester lead in a convenient adjacent socket, as long as it is uploaded, a dam sight quicker
J
 
I was under the impression that you tested the RCD time on each circuit that it was testing, presferably at the furthest point to ensure that the trip times where ok?
 
This is one thing I have had to concede I always held that you should test the circuit, however clearly this is wrong as you should have already tested the circuit for all the usual tests, the test should be carried out between the load side of the RCD on the line and CPC of the associated circuit, as I say in my opinion an adjacent socket with appliances off serves this purpose.
J
 
I tend to test at a socket/light fitting, then if anything 'odd' shows up I test it at the board compare the results and go from there.

As Murdoch pointed out though, a slow RCD can frequently be brought back to spec with a few presses of the manual test button.
 
I had a Legrand 63amp 3 phase RCD fail a couple of weeks ago.

When it was first turned on it went bang, even with all the MCB's turned off, when I tried it again it shut down the whole system including the digital meter. After about 30mins, system cooled down and came back up on line with 230 volts present at each phase. RCD was badly scorched on the sides so ordered a new one and replaced. Cost of new one Euros 283.60 and thats trade price here in France.
 
i had a legrand 63amp 3 phase rcd fail a couple of weeks ago.

When it was first turned on it went bang, even with all the mcb's turned off, when i tried it again it shut down the whole system including the digital meter. After about 30mins, system cooled down and came back up on line with 230 volts present at each phase. Rcd was badly scorched on the sides so ordered a new one and replaced. Cost of new one euros 283.60 and thats trade price here in france.

£200+ ???
J
 
But if the rcd is requiring the manual button pumping a few times then obviously the rcd inside is breaking and needs replacing, there is no guarantee that in 1 yrs time when joe public needs the rcd to trip under fault that it will trip
 
But if the rcd is requiring the manual button pumping a few times then obviously the rcd inside is breaking and needs replacing, there is no guarantee that in 1 yrs time when joe public needs the rcd to trip under fault that it will trip

It's not breaking, the mechanism is sticking. That's why the should be (and a label to that effect is put on the CU) manually tripped annually. No one bothers though, consequently they stick. Working the mechanism a few times usually frees them off.
 

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