RCCD in meter box randomly tripping
- Thread starter FrogParty
- Start date
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Would like to know the model though. If it is not an S type then I would expect it to trip as any earth leak over 100mA will set it off.
I've never seen an S type RCBO. A PHOTO might be interesting.
Sorry, I got my facts a bit muddled.
The offending RCD was a 100A 100mA time delayed RCCB (not an RCBO) from Control Gear Direct.
To reprise: the CU is made by Control Gear Direct, badged as Curve by Denmans, populated by 30mA RCBOs by same. The entire TT system, including 8m of SWA running under the house, was then protected by a 100A 100mA time delayed RCCB (not an RCBO) located next to the meter.
This external 100mA RCD from Control Gear Direct, has randomly tripped since the meter was first installed. The electricians replaced it with another of the same make with no improvement. Finally, having "tested everything" and blamed the weather, they replaced it with one made by Legrand and the problem immediately went away. Since then we have not tripped out, used the PV inverter and power tools that would have caused trips before and all is well.
This is what we currently have
I now believe that the nuisance trips (there really does not seem to be an earth leakage problem anywhere) could be a matter of cheap components. Control Gear Direct is not Wylex or MK, but some people like their CU because of the head space, so that is possibly fine (I am not a brand person). But checking the cost of the 100mA RCCB the Curve/CGD unit is £40 but the Legrand costs £150. I think that the noise was too much for the cheap kit, does that make sense?
sadly it is a low-price brand and does not have a reputation for quality and reliability, as you may have picked up.
Other good brands are available for less than £150, but a time-delayed (S-type) 100A 100mA RCD does tend to be expensive as it is not sold in great numbers.
e.g. http://www.tlc-direct.co.uk/Products/MK6400.html
I could not find retail price for the MEM one.
Looking at your photo of the LeGrand, I don't see any labelling to indicate that it is time-delayed (S-type). Can you see a part number?
Other good brands are available for less than £150, but a time-delayed (S-type) 100A 100mA RCD does tend to be expensive as it is not sold in great numbers.
e.g. http://www.tlc-direct.co.uk/Products/MK6400.html
I could not find retail price for the MEM one.
Looking at your photo of the LeGrand, I don't see any labelling to indicate that it is time-delayed (S-type). Can you see a part number?
There also doesn't appear to be any over current protection between the meter & the SWA ..... which there should be!
And the SWA doesn't appear to be terminated using a proper gland. Please show us a pic of the cutout/meter/RCD/swa taken from a little further back.
And the SWA doesn't appear to be terminated using a proper gland. Please show us a pic of the cutout/meter/RCD/swa taken from a little further back.
It does have a small square with an "S" in it next to another with a "~", guessing that 6027 11 is the part number. Is Legrand one of the better makes?
OK, here is a picture of what is in the meter box.
Can you confirm if the Grey core is unused or concerted to something els?
The armour of the SWA doesn't appear to be earthed at the supply end
Also was the new RCCB tested or just put in could be that the new unit is actually faulty and not tripping when its meant to
also you say its a TT system, with the earth at the cut out it would appear that there is some sort of DNO earth provided, if your on your own transformer this could be a TNS
The armour of the SWA doesn't appear to be earthed at the supply end
Also was the new RCCB tested or just put in could be that the new unit is actually faulty and not tripping when its meant to
also you say its a TT system, with the earth at the cut out it would appear that there is some sort of DNO earth provided, if your on your own transformer this could be a TNS
Please note the first post
So we assume this is a TT.
From that SWA, the black would be earth and I assume the grey is a sleeve over the steel armour. I guess these both go to the MET where they hold hands with the conductor from the earth rod.
If this were done properly the SWA should be terminated in a gland.
So we assume this is a TT.
From that SWA, the black would be earth and I assume the grey is a sleeve over the steel armour. I guess these both go to the MET where they hold hands with the conductor from the earth rod.
If this were done properly the SWA should be terminated in a gland.
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