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?