Need a portable RCBO to trip faster than general

[Energizer]

You're obviously finding out new things but if you didn't even know that S type devices existed, it just about sums up the knowledge involved in your ideas.

What do you want to say? What standard are you applying to estimate the knowledge ''involved in ideas''?

 

[littlespark]

The testing method you are using is inappropriate. You will damage both RCDs and your installation will with lose power because the upstream rcd no longer turns on, or it will become welded shut, and not trip on fault. Making it unsafe.

The 10 or 30mA is the fault current. If you could simulate an 11, 12, 13 mA fault, then you will find the 10 trips and the 30 doesn’t.
Testing live to earth is creating a massive current.
Voltage divided by resistance = amps.
So 230, or 110 or whatever you use divided by near enough zero is going to give very high current, albeit for a very short time.
In fact, this won’t just be stressing the rcd’s but also any cable, socket pins, circuit breakers that the current has to pass through.


There has been explanations already from professional electricians and the general consensus is that it cannot be done.

Your only solution is to separate the circuit you want from the upstream rcd, either giving it its own rcd, reducing the overall total “resting” earth leakage on each or if permissible, running an non RCD protected circuit to where it needs to be and fitting the rcd there.

 

[Energizer]

The testing method you are using is inappropriate. You will damage both RCDs and your installation will with lose power because the upstream rcd no longer turns on, or it will become welded shut, and not trip on fault. Making it unsafe.

I assume the risk and I'll buy new RCD in case of damage. No problem

The 10 or 30mA is the fault current. If you could simulate an 11, 12, 13 mA fault, then you will find the 10 trips and the 30 doesn’t.
Testing live to earth is creating a massive current.
Voltage divided by resistance = amps.
So 230, or 110 or whatever you use divided by near enough zero is going to give very high current, albeit for a very short time.
In fact, this won’t just be stressing the rcd’s but also any cable, socket pins, circuit breakers that the current has to pass through.

I wrote before many times - when you plug in a shorted to the ground device, there is no resistance, there are amps leaking for some ms - no stress for the wires and the RCD is doing their job. Manufacturers did the same thing thousands of times in the lab for measurements and to check when the device will fail.
The RCD is designed to protect people. A human body have different resistance depending on different factors, humidity, etc, but the faulty device don't have resistance. The current is searching the shortest way, allways.
In real life this type of fault is happening very rarely when we don't have a multimeter to test the device before plug in, so no stress for RCD or wires, it will not trip every day. I allways push the test button before and after my experiments to verify if the device is still operational.

There has been explanations already from professional electricians and the general consensus is that it cannot be done.

Well, sorry for my curiosity and motivation to find a solution. For me, "it cannot be done" is the last thing, when I don't have any ideas and there really are no more solutions, proved by real tests or, not economically viable

Your only solution is to separate the circuit you want from the upstream rcd, either giving it its own rcd, reducing the overall total “resting” earth leakage on each or if permissible, running an non RCD protected circuit to where it needs to be and fitting the rcd there.

I added this solution to the list of potential solutions, the same thing with selective tripping solution that requires changing the RCD type, or intelligent RCD, resetting itself safely after a nuisance trip. These solutions are valid but not everywhere.

 

[Energizer]

Today I performed some tests and I obtained what I want without modifying anything in the house. I modified only my portable RCD power strip. When I plug into my security power strip a faulty device (residual current fault) - then my power strip goes off instantaneously and isolate the faulty circuit from the rest of the house, but the main RCD 30mA it's still on! The portable RCD 10mA trips faster than general. Repeated many times - works like a charm. That's what I wanted

Next step is to integrate all in one multi protection RCBO - leakage, short, overload protection, or, add short circuit (phase-neutral) protection to existing circuit. Ultra fast fuse, resetable fuse ... how to deal with shorts ?

 

[Energizer]

If I understand correctly, my portable RCCB has already an integrated fuse rated 63A and 10000 transient cycles.
At 4 transient cycles per day, this fuse will operate for about 6,5 years before blowing up, and at 1 cycle per month - 833 years. I'm right?

 

[mainline]

Today I performed some tests and I obtained what I want without modifying anything in the house. I modified only my portable RCD power strip. When I plug into my security power strip a faulty device (residual current fault) - then my power strip goes off instantaneously and isolate the faulty circuit from the rest of the house, but the main RCD 30mA it's still on! The portable RCD 10mA trips faster than general. Repeated many times - works like a charm. That's what I wanted

Next step is to integrate all in one multi protection RCBO - leakage, short, overload protection, or, add short circuit (phase-neutral) protection to existing circuit. Ultra fast fuse, resetable fuse ... how to deal with shorts ?

What modifications have you made ? Or are you keeping it secret for now due to applying for patent etc.

 

[littlespark]

What modifications have you made ?

Knackered the main rcd I think.

Otherwise, you’ve managed to invent a device that will discriminate between two 40ms RCDs in line.
I’m sure the manufacturers would be interested in investing, because up til now, after 40 years or so, no one has come up with a solution.

 

[mainline]

Knackered the main rcd I think.

Otherwise, you’ve managed to invent a device that will discriminate between two 40ms RCDs in line.
I’m sure the manufacturers would be interested in investing, because up til now, after 40 years or so, no one has come up with a solution.

Yes and it also has zero resistance, we are now destined to carry high currents with cables the size of a hair.

 

[DPG]

This is a prime case of a little knowledge being a dangerous thing.

 

[Energizer]

Knackered the main rcd I think.

Wrong. I tested the main RCD - it works

Yes and it also has zero resistance, we are now destined to carry high currents with cables the size of a hair.

Wow, you have the ability to measure the resistance and size of cables at distance?

This is a prime case of a little knowledge being a dangerous thing.

Well, if a little knowledge is dangerous thing, I will not share my solution (to keep the people in safety). They should use what they find on the market and what the certified electricians are saying and never try testing like me, because it's dangerous
For me it works (without breaking any safety rules) and I'm happy

 

[DPG]

Wrong. I tested the main RCD - it works

Wow, you have the ability to measure the resistance and size of cables at distance?

Well, if a little knowledge is dangerous thing, I will not share my solution (to keep the people in safety). They should use what they find on the market and what the certified electricians are saying and never try testing like me, because it's dangerous
For me it works (without breaking any safety rules) and I'm happy

Great stuff, glad all worked out OK. Engineering excellence.

 

[brianmoooore]

So what were the figures for the main RCD that you claim to have tested?

 

[ipf]

Great stuff, glad all worked out OK. Engineering excellence.

The latest 'Nikola Tesla'...in France?

 

[mainline]

So what were the figures for the main RCD that you claim to have tested?

He pressed the test button.

 

[mainline]

The latest 'Nikola Tesla'...in France?

You maybe laughing now, but before long his name will be up in lights, that is if they haven't caught fire or tripped.

 

[Energizer]

So what were the figures for the main RCD that you claim to have tested?

It has a test button. The RCD works normally. No melted/welded contacts

 

[brianmoooore]

Little bit more to testing a RCD than pushing the button!

 

[mainline]

It has a test button. The RCD works normally. No melted/welded contacts

It seems that your laboratory where you do all the experiments and testing for people's safety seems to consist of a piece of wire and your finger.

 

[Energizer]

Little bit more to testing a RCD than pushing the button!

Not today

 

[Energizer]

It seems that your laboratory where you do all the experiments and testing for people's safety seems to consist of a piece of wire and your finger.

You are thinking wrong, or it's just a sarcasm and banter.
Don't worry about my safety. This security device I will use for months, only me. Nobody will be hurted, I promise

 

[Energizer]

Please don't transform this thread into a security lesson. I appreciate that electricians remember to me about the dangers of electricity, but not so often, please

 

[littlespark]

Can you see it from our perspective?

An RCD is a safety device. By altering it, and you haven’t described how it’s been altered… you may have changed its properties….

Without testing with a designated RCD tester, you cannot be certain it will function within its designed limits.

The portable strip must trip at 10mA and must trip within 40ms. The rcd tester can measure these minuscule amounts. The ramp test function can also give you the actual threshold in mA it trips at as well as the time in ms.

As professionals we cannot say that what you are doing is correct.
Other members of the public might copy your approach and not be so lucky.

Just to reiterate again. Touching live to earth deliberately is not a safe method of testing RCDs.

 

[Energizer]

Yes, I can perfectly see it from your perpective and I thanks all for information.
I mentioned before that I take precautions and I assume the risk. No one is invited to repeat what I'm doing.
Now, what if I will say, my tests are performed on a special stand on a lab and not in a real home? What if the tested RDC will not be used anymore after tests (even if they are still doing their job) ? It will calm down the spirits, I think.
All are saying - it will burn, it will be knackered, you will be electrocuted etc, but no one is trying to calculate how many time is needed to heat a 30m 14awg wire until it starts smocking. I know there is many variables in the formula. My calculations based on what I have in the lab shows that melting a 14awg wire will take several seconds, but the RCD triggers within 40ms.
The thermal camera is showing that there is no temperature rise in the tested wires. The RCD is disconnecting so fast that there is no time to rise from 20C to copper incandescence temperature. The manufacturers designed their devices to protect the circuit in such situations. If the manufacturers will think like you and use only safe tests, then in real life their device will kill somebody because in real life there is imprevisible situations, non safe situations. That's why is important to think about it. Nobody knows when your RCD will be faulty. If you doubt about your RCD - you just buy a new one and remplace it, right ?

 

[ipf]

I'll give you one thing, Energizer......your english is very good. Spelling a bit 'iffy' and the odd unintelligible word, like 'imprevisible' (should be 'unpredictable') but overall well on song.
Good effort, Well done.

 

[Energizer]

Sorry for my English. I work on it improvement

 

[brianmoooore]

I like imprevisible. Really should be a word.

 

[mainline]

I like imprevisible. Really should be a word.

English​

Adjective​

imprevisible (comparative more imprevisible, superlative most imprevisible)

1. (rare) unforeseeable

Antonyms: foreseeable, previsible

 

[brianmoooore]

So it's a word already, then. Spellchecker doesn't seem to know that.

 

[mainline]

So it's a word already, then. Spellchecker doesn't seem to know that.

A French one would

 

[littlespark]

Spellcheck didn’t understand “diarreah” on my recent “good morning” thread post…..

No… not what you’re thinking!