RCD - Ramp test

[matt.leung]

just done a ramp test on a 30mA RCD and it was tripping at 23mA.

what is the main reason for this......

 

[Andy™]

it shouldnt trip at 1/2, but can at anything above. so nothing wrong with 23mA. many will trip at 20mA. it doesnt wait for it to be exactly 30mA

 

[rugbymacc]

most will trip around this figure....

as it airs on the side of caution

 

[matt.leung]

cos i was told by a tutor that they should trip around 17mA...

 

[rugbymacc]

you'll get more nuisance tripping at that level

 

[matt.leung]

would i suggest that i should replace the RCD or not, even that the ramp test tripped at 23mA

 

[rugbymacc]

you need check the tripping times as well (millisecond)

 

[m4tty]

I think even if you changed it the new one would still trip between 21ma and 23ma. Its the average hth

 

[Andy™]

ramp test does not have to be carried out anyway. as long as it passed 1x & 5x, your good

 

[matt.leung]

the reason why i did the ramp test is that it seems to be very sensitive as i have been doing quite a lot of work for the neighbour over the last couple of weeks....

 

[betty swollocks]

i would agree, highest reading i've had was 27ma, lowest about 19ma but that was a really old one and was 'nuisance' tripping frequently

 

[matt.leung]

this rcd is about 2 or 3 yr's old... i was not the spark that installed it, so cant tell u exactly when it was installed.. this age is just a guess...

 

[monkey5]

it just needs to trip within 30mA not at 30mA. mine normally trip bout 23-25mA have always found anything less than 20mA is too low and will normally nuisance trip (just my opinon

hth wayne