The fastest RCBO in the world

[Energizer]

What is the fastest RCBO you know?
Fastest is meaning it has the lowest trip times.

 

[littlespark]

Do you mean measured time, or design?

I don’t think any are designed less than 40ms… but there are time delayed ones.

Recent eicr was Hager 63A type AC in a dual rcd consumer unit… Tripped at 35 and 39 ms. Just within the 40, but there are other down at 19…. Can’t remember what make, but possibly a brand new fusebox RCBO.

 

[Energizer]

Do you mean measured time, or design?

I mean measured time.
I searched in the datasheet and techical description of the dozens of RCBO - no one word about trip time.

 

[littlespark]

The regulations for final circuits ask for 40ms, or it may just be written as 0.04s

You can get time delayed rcd/RCBO which are longer times, but are fitted upstream, protecting a number of circuits.

Domestic installations are only 40 ms.

 

[Energizer]

There is no RCBO without delayed trip? I mean trip time=0, instantaneous trip ?

 

[DPG]

There is no RCBO without delayed trip? I mean trip time=0, instantaneous trip ?

There are non-delay RCDs yes. But there is no such thing as instant - they all take a finite amount of time to trip, even though it may only be a few milliseconds.

 

[Intoelectrics]

There is no RCBO without delayed trip? I mean trip time=0, instantaneous trip ?

There is no such thing as instantaneous cause and effect in the way you are imagining it. Even if the device operated at the speed of light, (around 300,000 Km per second = 186,282 miles per second) it would still take an extremely small amount of time to operate . Albeit, this would be so fast, possibly immeasurable, so for all intent purposes as close to your instantaneous as you could get.

Even at this high speed the sun's light doesn't reach Earth until around 8.3 minutes after it was initially propagated, and the nearest star to ours, just over 4 years!

But things start to get even more mind boggling when you delve into Albert Einstein's relativity which describes the relationship between space, time, speed and measurements.

 

[littlespark]

There is no such thing as instantaneous cause and effect in the way you are imagining it. Even if the device operated at the speed of light, (around 300,000 Km per second = 186,282 miles per second) it would still take an extremely small amount of time to operate . Albeit, this would be so fast, possibly immeasurable, so for all intent purposes as close to your instantaneous as you could get.

Even at this high speed the sun's light doesn't reach Earth until around 8.3 minutes after it was initially propagated, and the nearest star to ours, just over 4 years!

But things start to get even more mind boggling when you delve into Albert Einstein's relativity which describes the relationship between space, time, speed and measurements.

Alright, Spock…. It’s too early in the morning.


You do get time delayed protection that may cover several circuits, but each of these final circuits have the 40ms limit.
A large enough fault will of course trip a time delayed much faster.

 

[Intoelectrics]

Alright, Spock…. It’s too early in the morning

I'm a member of a few science forums, its a passion of mine. So my apologies, I just find it so fascinating and just wanted to share with bore you all.

 

[Rockingit]

The question has to be...... why the question? What is it that you're wanting to do that requires a really fast disconnect time?

 

[brianmoooore]

On a 50Hz AC circuit, the minimum trip time is dependant on what point in a cycle the fault occurs. If the fault occurs as the AC waveform crosses zero, there is no design of RCD possible that would switch off 'instantly'.

 

[Rockingit]

What is the fastest RCBO you know?
Fastest is meaning it has the lowest trip times.

Right..... so making an assumption that we're talking about a 5x figure (as most faults are in fact likely to be close to ADS levels) then typically in my experience of testing AC types I'm seeing numbers around 8ms - 12ms area for most manufacturers. HOWEVER - in type A RCD devices we are now typically seeing longer disconnect times at 1x than we used to (and we no longer have to test at 5x). So, if you have two RCD's in series it is still a game of chance as to which may trip first and as others have said is also entirely dependant on a heap of other factors and physics at play.

If you're experiencing nuisance tripping, as I suspect is the case, then you need to look at the cause of the fault, not the characteristics of the protecting devices.

 

[Energizer]

There is no such thing as instantaneous cause and effect in the way you are imagining it. Even if the device operated at the speed of light, (around 300,000 Km per second = 186,282 miles per second) it would still take an extremely small amount of time to operate . Albeit, this would be so fast, possibly immeasurable, so for all intent purposes as close to your instantaneous as you could get.

Even at this high speed the sun's light doesn't reach Earth until around 8.3 minutes after it was initially propagated, and the nearest star to ours, just over 4 years!

But things start to get even more mind boggling when you delve into Albert Einstein's relativity which describes the relationship between space, time, speed and measurements.

Extremely small amount of time is the key to my problem.
Logically, to measure any current, leakage current or normal current, we need a time, small amount of time. Now is to manufacturers to build different devices with different sensibility for different applications. I would like to identify the most sensitive RCB.
The electrical wires length in the house comparing to distance to the Sun is nothing, so I assume the speed of current is instantaneous, in my house. The distance between two RCB is too small to have any delay so the waveform is synchronous, I think.

 

[Energizer]

Right..... so making an assumption that we're talking about a 5x figure (as most faults are in fact likely to be close to ADS levels) then typically in my experience of testing AC types I'm seeing numbers around 8ms - 12ms area for most manufacturers. HOWEVER - in type A RCD devices we are now typically seeing longer disconnect times at 1x than we used to (and we no longer have to test at 5x). So, if you have two RCD's in series it is still a game of chance as to which may trip first and as others have said is also entirely dependant on a heap of other factors and physics at play.

If you're experiencing nuisance tripping, as I suspect is the case, then you need to look at the cause of the fault, not the characteristics of the protecting devices.

Yes, you are right. I have two RCD in cascade, first in the main distribution board and second is integrated in the portable power strip.
I had the same thoughts about nuisance tripping. When I touch the phase wire to the earth, this may cause different peaks so this nuisance could trigger both RCD (not confirmed by measure). What about integrate an anti nuisance filter in the power strip?

 

[DPG]

Out of interest, why do you keep experiencing this regular tripping of your RCDs?

 

[brianmoooore]

Out of interest, why do you keep experiencing this regular tripping of your RCDs?

Exactly! You seem to be more intent on shooting the messenger, rather than listening to his warning and acting upon it.

 

[Energizer]

Out of interest, why do you keep experiencing this regular tripping of your RCDs?

I'm searching to have a security device, in this case a power strip with integrated RCD to trigger while the upstream RDC remains ON. Is a question of sensitivity and rapidity. When you buy a fast and sensible RCD that is intended to trigger faster (to protect sensitive devices for example) than other but in real life is useless because I still need to open the main distribution board to reactivate the main RCD. With this portable 10mA RCD or without - is the same thing, the main RCD is triggering. There should be a way to protect small circuits without cutting off all the house.

 

[DPG]

I'm searching to have a security device, in this case a power strip with integrated RCD to trigger while the upstream RDC remains ON. Is a question of sensitivity and rapidity. When you buy a fast and sensible RCD that is intended to trigger faster (to protect sensitive devices for example) than other but in real life is useless because I still need to open the main distribution board to reactivate the main RCD. With this portable 10mA RCD or without - is the same thing, the main RCD is triggering. There should be a way to protect upstream small circuits without cutting off all the house.

But if you are getting repeated tripping of an RCD then you have something wrong somewhere. Are you getting tripping of your RCD?

 

[brianmoooore]

A 10mA RCD trips between 5mA and 10mA. A 30mA RCD trips between 15mA and 30mA. Any differential fault current that exceeds the tripping current of that particular 30mA RCD is equally likely to trip either or both RCDs.
You will only get discrimination if the fault current exceeds the tripping current of the 10mA RCD but is less than that of the 30mA one.
You can, of course, replace the 30mA RCD with a 'S' type delayed version, but then the rest of the circuits supplied by that RCD will not have the required level of protection.

 

[Energizer]

But if you are getting repeated tripping of an RCD then you have something wrong somewhere. Are you getting tripping of your RCD?

No, I don't have repeated tripping. I simulate a fault. Both RCD shuts off when I want only one to shut off, the closest to me and to the fault

 

[Energizer]

A 10mA RCD trips between 5mA and 10mA. A 30mA RCD trips between 15mA and 30mA. Any differential fault current that exceeds the tripping current of that particular 30mA RCD is equally likely to trip either or both RCDs.
You will only get discrimination if the fault current exceeds the tripping current of the 10mA RCD but is less than that of the 30mA one.
You can, of course, replace the 30mA RCD with a 'S' type delayed version, but then the rest of the circuits supplied by that RCD will not have the required level of protection.

When I do the experiment, I touch the phase to the earth wire. There is no resistance (resistance of the wires and the contact point) so the leakage current is maximal. I don't measured the leakage current, but let's say it's 1 A. The fault is located after 30mA and after 10mA RCD. So if the current reaches from 0A to 1A instantaneously, then both RCD will shut off. I'm thinking correctly? What if using a coil in second circuit to slow a little bit the current in the moment of connection and give time to the RCD 10mA to cut off?

 

[Rockingit]

When I do the experiment, I touch the phase to the earth wire. There is no resistance (resistance of the wires and the contact point) so the leakage current is maximal. I don't measured the leakage current, but let's say it's 1 A. The fault is located after 30mA and after 10mA RCD. So if the current reaches from 0A to 1A instantaneously, then both RCD will shut off. I'm thinking correctly? What if using a coil in second circuit to slow a little bit the current in the moment of connection and give time to the RCD 10mA to cut off?

Both RCD's are seeing the same amount of fault current (usually). It doesn't matter if you have a 1A RCD upstream of a 1mA RCD if the fault current is 500A! The only difference, as you've identified, is which trips first.

What you can get are auto-resetting RCD's such as Gewiss' exclusive intelligent RCD, resetting itself safely after a nuisance trip - https://www.voltimum.co.uk/articles/gewiss-exclusive-intelligent-rcd

 

[Energizer]

Both RCD's are seeing the same amount of fault current (usually). It doesn't matter if you have a 1A RCD upstream of a 1mA RCD if the fault current is 500A! The only difference, as you've identified, is which trips first.

What you can get are auto-resetting RCD's such as Gewiss' exclusive intelligent RCD, resetting itself safely after a nuisance trip - https://www.voltimum.co.uk/articles/gewiss-exclusive-intelligent-rcd

Which trips first, that's the question.
Interesting I didn't know about existence of stuff device as ARD, intelligent RCD. Thanks for information

 

[littlespark]

If you are touching phase to earth as an experiment, you are creating a massive fault current. I wouldn’t be surprised if the upstream 30mA is knackered now.

We are now getting away from one rcd covering several circuits to one RCBO per circuit. More expensive of course, but cuts down on nuisance trips.
Only the faulty circuit trips, leaving others on.

 

[DPG]

Which trips first, that's the question.
Interesting I didn't know about existence of stuff device as ARD, intelligent RCD. Thanks for information

It doesn't really matter which trips first. The point is that on a fault like you are describing both devices will start to trip. One may well take slightly longer to complete the operation, but both will trip once the operation has begun.

 

[Intoelectrics]

Extremely small amount of time is the key to my problem.
Logically, to measure any current, leakage current or normal current, we need a time, small amount of time. Now is to manufacturers to build different devices with different sensibility for different applications. I would like to identify the most sensitive RCB.
The electrical wires length in the house comparing to distance to the Sun is nothing, so I assume the speed of current is instantaneous, in my house. The distance between two RCB is too small to have any delay so the waveform is synchronous, I think.

For most intent purposes what we perceive as instantaneous can be described as such, especially such that our senses and reactions are way way slower than the speed in which electricity and light propagates.

But there is no such thing as a cause and effect mechanism which is instantaneous in the way you imagine it.

 

[Energizer]

If you are touching phase to earth as an experiment, you are creating a massive fault current. I wouldn’t be surprised if the upstream 30mA is knackered now.

We are now getting away from one rcd covering several circuits to one RCBO per circuit. More expensive of course, but cuts down on nuisance trips.
Only the faulty circuit trips, leaving others on.

Yes, this in an experiment, test. In real life this happen when a defective device has a fault of insulation - the phase is touching the ground. I'm testing different electrical equipment that could have short circuit or leakage problem. I have seen equipments that works fine 5 minutes then when the resistance is hot it cause short or leakage to the ground and the general RCD switchs off.
Can you give me and example of what you are using to cut off only the faulty circuit? This is exactly what I need. Thanks

 

[DPG]

Yes, this in an experiment, test. In real life this happen when a defective device has a fault of insulation - the phase is touching the ground. I'm testing different electrical equipment that could have short circuit or leakage problem. I have seen equipments that works fine 5 minutes then when the resistance is hot it cause short or leakage to the ground and the general RCD switchs off.
Can you give me and example of what you are using to cut off only the faulty circuit? This is exactly what I need. Thanks

RCBOs are used to give earth leakage protection to individual circuits. They combine over current and earth leakage protection.

If one trips then you only lose that circuit, not the whole system.

 

[Energizer]

It doesn't really matter which trips first. The point is that on a fault like you are describing both devices will start to trip. One may well take slightly longer to complete the operation, but both will trip once the operation has begun.

Here someone reported it managed to cut off only faulty circuit. This is why I'm searching for

 

[DPG]

Here someone reported it managed to cut off only faulty circuit. This is why I'm searching for

RCBOs - see posts above

 

[Energizer]

RCBOs are used to give earth leakage protection to individual circuits. They combine over current and earth leakage protection.

If one trips then you only lose that circuit, not the whole system.

So you mean individual circuit is to have dedicated power outlet in the wall, one RCBO per outlet? Maybe at home this is possible to do. But at work or another home where you can't modify the main distribution board how to be? Any idea?
I have an idea - to build Arduino controled relay - 3 relays, phase, neutral and earth. The current sensor is measuring and comparing the current - if phase and neutral are equal - then OK, but if is detected very small leakage to earth, then the microcontroller shuts off all 3 relays. The Arduino processor and the Relay it is enough fast to perform this operation faster than regular RCBO on the market?

 

[DPG]

So you mean individual circuit is to have dedicated power outlet in the wall, one RCBO per outlet? Maybe at home this is possible to do. But at work or another home where you can't modify the main distribution board how to be? Any idea?
I have an idea - to build Arduino controled relay - 3 relays, phase, neutral and earth. The current sensor is measuring and comparing the current - if phase and neutral are equal - then OK, but if is detected very small leakage to earth, then the microcontroller shuts off all 3 relays. The Arduino processor and the Relay it is enough fast to perform this operation faster than regular RCBO on the market?

You're still missing the point that the other device has already started the tripping process.

 

[littlespark]

Ive just noticed the OP is in France.... so not sure of how their regs demand when and where to have rcd protection.

 

[Energizer]

You're still missing the point that the other device has already started the tripping process.

I understand this. In your opinion, it's impossible to do what I described above?

 

[DPG]

I understand this. In your opinion, it's impossible to do what I described above?

I wouldn't say impossible, but I think it would be very difficult to get reliable and repeatable results.

 

[westward10]

I think there is a company called Usain who make record breaking fast devices.

 

[James]

I think there is a company called Usain who make record breaking fast devices.

Usain Volt?

 

[Energizer]

I think there is a company called Usain who make record breaking fast devices.

You think? Well, if you find the contacts of this company, please post here to help the community

 

[westward10]

You think? Well, if you find the contacts of this company, please post here to help the community

Think about it.

 

[Energizer]

Think about it.

Thanks for suggesting a ''nice company who makes super fast breaking devices'', but I think about useful information that I got from another members. And you still think that there somewhere is this nice company or you can share with us more information about it?

 

[littlespark]

I think maybe sarcasm and banter has got lost in translation.

 

[westward10]

Beggars belief.

 

[Energizer]

I don't think that the users who are encountering the same problem as me will be happy to scroll down and read a lot of posts with sarcasm and banter in this thread or maybe I'm wrong... The sarcasm doesn't help to solve the problem. Useless posts are just a waste of time. Sorry for the electricians who likes to laugh

 

[westward10]

I apologise for side tracking the thread with a touch of humour, I thought it would attract nothing more than a laugh. Even my girlfriend who has zero interest in sport would have understood the reference to Usain.

 

[Energizer]

I apologise for side tracking the thread with a touch of humour, I thought it would attract nothing more than a laugh. Even my girlfriend who has zero interest in sport would have understood the reference to Usain.

Thanks for your humour. I knew it.