C
Craig Rogers
Hello,
Newcomer to the forum, so hello all.
Just to clarify, although I understand most of my way around the regs and workings, still get an approved guy to to any work......just thought I'd get that out of the way!
Anyhow, I have an old property that fed by good old overhead Live/Neutral so have a TT earthing pole.
When the property was renovated, the whole place was re-wired and a new CU was installed. As the meter and fuse is around 4m from the CU, there is also an Type S 100amp RCD incomer protecting the tails to the CU. The CU has been recently replaced as the incomer was tripping and on investigation, it was installed in a strange way, it was a single 30amp RCD CU and the lighting was being protected by the RCD and the socket rings on the non-protected side, hence why the incomer was tripping.
The original CU also had a 40amp mcb providing a feed to another small CU (without RCD) in an outbuilding.
I suspect the fault lies within the outbuilding and of course, the main incomer would trip.
Therefore, the CU has been replaced with a 17th edition one configured in High Integrity with dual RCDs splitting the lights and rings and also an RCBO feeding the outside CU.
However, and yes, I finally get to the question!....... As this RCBO is single pole, am I correct in thinking that if there is a N-E fault then as the RCCB is single pole it might not trip and still cause the incomer RCD to trip instead taking out the whole CU. Or should the RCCB still trip out first?
We had a trip yesterday where again the main incomer RCD tripped. This is causing a big issue as we have a monitored alarm which is losing power. It's battery backed up, but if we are away for a few days will cause the battery to drain and has actually destroyed a battery in the past.
It could just be a faulty Type S 100ma RCD (it does tend to buzz on high throughput) as there is never a common reason for it to trip, or am I right in my thinking that as a Single Pole RCBO doesn't break the Neutral (and remember is on a TT system) which could cause the incomer to trip.
Many thanks for your help in advance.
Newcomer to the forum, so hello all.
Just to clarify, although I understand most of my way around the regs and workings, still get an approved guy to to any work......just thought I'd get that out of the way!
Anyhow, I have an old property that fed by good old overhead Live/Neutral so have a TT earthing pole.
When the property was renovated, the whole place was re-wired and a new CU was installed. As the meter and fuse is around 4m from the CU, there is also an Type S 100amp RCD incomer protecting the tails to the CU. The CU has been recently replaced as the incomer was tripping and on investigation, it was installed in a strange way, it was a single 30amp RCD CU and the lighting was being protected by the RCD and the socket rings on the non-protected side, hence why the incomer was tripping.
The original CU also had a 40amp mcb providing a feed to another small CU (without RCD) in an outbuilding.
I suspect the fault lies within the outbuilding and of course, the main incomer would trip.
Therefore, the CU has been replaced with a 17th edition one configured in High Integrity with dual RCDs splitting the lights and rings and also an RCBO feeding the outside CU.
However, and yes, I finally get to the question!....... As this RCBO is single pole, am I correct in thinking that if there is a N-E fault then as the RCCB is single pole it might not trip and still cause the incomer RCD to trip instead taking out the whole CU. Or should the RCCB still trip out first?
We had a trip yesterday where again the main incomer RCD tripped. This is causing a big issue as we have a monitored alarm which is losing power. It's battery backed up, but if we are away for a few days will cause the battery to drain and has actually destroyed a battery in the past.
It could just be a faulty Type S 100ma RCD (it does tend to buzz on high throughput) as there is never a common reason for it to trip, or am I right in my thinking that as a Single Pole RCBO doesn't break the Neutral (and remember is on a TT system) which could cause the incomer to trip.
Many thanks for your help in advance.
Last edited by a moderator:
