uksparks
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- Reaction score
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Hi,
I went to see a house today where their plug circuit on a 32A Wylex Type A RCBO keeps intermittently tripping each day.
Its a TNC-S, Wylex board with 6 protected by RCD and three on RCBO's. Board was changed 3 years ago.
The RCBO that's on the plug circuit keeps intermittently tripping. I checked all connections etc and nothing obviously wrong at the board.
What I have done is Ramp tested the RCBO to see what its tripping at and its going out at 15mA which is low, but I understand on the Wylex RCBO's this is not too uncommon. I said it could be an accumulation of leakages causing this. I put my ELCM round the tails which measured 13.7mA and round the main earth that was 21mA.
There a couple of outside sockets protected by RCD spurs, bit of SWA to the shed with another RCD ( in the shed there's a fridge and a freezer). The RCD spurs, ive left tripped for a moment to help eliminate the outside sockets.
I have checked all appliances for earth leakage when operating, I have a small extension with the earth wire exposed that I check with, all appliances were under 0.5mA each so nothing to bad there. Even disconnected and checked the boiler.
I did an RCD test on it, which was fine, nicely within limits, nothing abnormal on both 0 and 180, good Zs etc...
I am not sure why the person who changed the board used a Type A RCBO, actually all three of the RCBO's are Type A. I swapped the shower RCBO and the plug circuit RCBO round as they were both the same size (32A) and the shower ramped out at 18mA which again I think is a little on the low side.
I said to the bloke, without sounding useless, and spending more time looking at all accessories etc and carrying out more tests as only did basic bits today, I said it might be worth changing or try changing the plug circuit RCBO out for a new one Type AC and hope its got a better threshold.
Am I correct in thinking the Type A has something to do with being able to withstand more DC back voltages or something? Seems to ring a bell, ill be honest, I've never used a Type A so little knowledge of them.
I said try unplugging one appliance at a time and leaving it 24 hours before moving on to the next to see if you can pin it down at all. You see, it does it at like 6:30am, which instantly made me think immersion (which they have not got) or a boiler maybe, but the boiler seems to be ok even when on, so maybe would a valve cause it?
So really, why and when would you use a Type A RCD in a domestic environment and any pointers? I am normally quite good at pinning down these problems, but all the obvious appliances seem to be. I am guessing its going to be a Class 1 appliance but not too sure now. I feel the bloke who changed the board (NICEIC AC), made a nice job, but had a problem when he did which is why he went Type A on the RCBOs?
Any points much appreciated.
I went to see a house today where their plug circuit on a 32A Wylex Type A RCBO keeps intermittently tripping each day.
Its a TNC-S, Wylex board with 6 protected by RCD and three on RCBO's. Board was changed 3 years ago.
The RCBO that's on the plug circuit keeps intermittently tripping. I checked all connections etc and nothing obviously wrong at the board.
What I have done is Ramp tested the RCBO to see what its tripping at and its going out at 15mA which is low, but I understand on the Wylex RCBO's this is not too uncommon. I said it could be an accumulation of leakages causing this. I put my ELCM round the tails which measured 13.7mA and round the main earth that was 21mA.
There a couple of outside sockets protected by RCD spurs, bit of SWA to the shed with another RCD ( in the shed there's a fridge and a freezer). The RCD spurs, ive left tripped for a moment to help eliminate the outside sockets.
I have checked all appliances for earth leakage when operating, I have a small extension with the earth wire exposed that I check with, all appliances were under 0.5mA each so nothing to bad there. Even disconnected and checked the boiler.
I did an RCD test on it, which was fine, nicely within limits, nothing abnormal on both 0 and 180, good Zs etc...
I am not sure why the person who changed the board used a Type A RCBO, actually all three of the RCBO's are Type A. I swapped the shower RCBO and the plug circuit RCBO round as they were both the same size (32A) and the shower ramped out at 18mA which again I think is a little on the low side.
I said to the bloke, without sounding useless, and spending more time looking at all accessories etc and carrying out more tests as only did basic bits today, I said it might be worth changing or try changing the plug circuit RCBO out for a new one Type AC and hope its got a better threshold.
Am I correct in thinking the Type A has something to do with being able to withstand more DC back voltages or something? Seems to ring a bell, ill be honest, I've never used a Type A so little knowledge of them.
I said try unplugging one appliance at a time and leaving it 24 hours before moving on to the next to see if you can pin it down at all. You see, it does it at like 6:30am, which instantly made me think immersion (which they have not got) or a boiler maybe, but the boiler seems to be ok even when on, so maybe would a valve cause it?
So really, why and when would you use a Type A RCD in a domestic environment and any pointers? I am normally quite good at pinning down these problems, but all the obvious appliances seem to be. I am guessing its going to be a Class 1 appliance but not too sure now. I feel the bloke who changed the board (NICEIC AC), made a nice job, but had a problem when he did which is why he went Type A on the RCBOs?
Any points much appreciated.