It is accomplished by putting one on every branch circuit.

Wire quality, receptacles, and plugs are not significant. Appliances can leak many tens of microamps. Or sometimes as much as hundred microamps. One RCD means it must not trip when all appliances are leaking 100 or 200 microamps.

Originally, RCDs were only required on bathroom and kitchen circuits.

Interesting his how the guy who developed it also demonstrated it. He had his daughter in a bathtub. And threw a powered radio in that bathtub. I had to reread the article many times before I finally understood (accepted) it. That was back when radios did not use transistors. The technology is that old.

This post has been edited by westom: Oct 22 2019, 04:59 PM

great idea ... hope some manufacturer will design and sell cheaper RCCB s

Current price for some RCDs is as low at 60 rm. Some that are installed in the breaker box (as a circuit breaker) can be 250 rm.

This post has been edited by westom: Oct 22 2019, 05:05 PM

The lightning no need to strike your lightning arrestor or power line to cause trip. When lightning strikes nearby, voltage can be induced by electric and magnetic field, thus produce voltage and current surge. Electrical wiring in house also can get excited by nearby lightning. These wires are already passed the RCCB or ELCB you have at the power inlet.

The best protection is to have surge arrestor as close as possible to your appliances. So, other than RCCB/ELCB, your PC or any other sensitive devices should be plugged into sockets that has surge protector.

Note that most electronic devices are very sensitive to surge. Normal surge protection by using normal varistor like devices might not be fast enough for protection, unlike electrical appliances. It is also good to have a fast surge protector at DB, perhaps in micro seconds range.

Leakage current is always there in your house wiring. This is because your house wiring is lined close to each other between L and N. When you have an appliance running on another circuit, the AC will induced voltage on the wire next to it and generate a stray voltage (like air core transformer ). If you measure voltage between L and N on OFF state wire, you probably get reading perhaps even 20Vac. This is no load situation and it has low current. That is why you see your test pen lit up even when the switch is off. Normally, it will cause no problem in general.

For layman, just check your ELCB/RCCB,

household = use 100ma
factory and industrial = use 300ma

if your house is using 30ma and trip frequently, you may change to 100ma and see if that solve your problem

Above are local standard, all new houses are require to use 100ma RCCD, and 10ma for water heater.

Then we put numbers to it. A lightning strike nearby to a long wire antenna (designed to be most sensitive to E-M fields) can result in thousands of volts on that antenna wire. Then connect a one milliamp Neon glow lamp (ie NE-2) to that antenna lead. Voltage then drops to maybe 60 volts. Because the induce surge has high voltage if current does not flow. And has near zero voltage if even less than one milliamp flows.

Induced surges are made irrelevant by what is already inside every electrical device.

Lightning struck a lightning rod. That means maybe 20,000 amps was flowing down the lightning rod's hardwire to earth. Just 1.3 meters away, inside, was an IBM PC. It did not even blink. And either did any other office electronics. That was a major E-M field confronting electronics - that did not even cause a software program to flicker. Because the destructive power of nearby E-M fields is overhyped by speculation. And does not exist once we include relevant numbers.

A tree was struck by lightning. Some ten meters distant, a cow died. Wild speculation assumes the cow was killed by an induced surge. Of course not. Lightning is a connection from a cloud (maybe 3 km up) to earthborne charges (maybe 4 km distant). That path also went up the cows hind legs and down its fore legs. What only observation speculated was an induced surge, in reality, was a direct strike. Conclusions only from observation create junk science. Once the many facts (with numbers) are learned, then that observation results in a completely different conclusion.

Nearby lightning strikes are either direct strikes or do not do damage. Nearby strikes that would trip an ELCD/RCD must somehow create what trips it. Not a voltage. A current that exceeds 100 ma. Induced surges just do not have that current. But many assume it was a induced surge rather than discover it was actually a direct strike.

Furthermore an ELCD/RCD requires that current to flow for tens of milliseconds or longer. Lightning is a microseconds event. too short to trip it. Something completely different (ie a follow-through current) may be relevant. But that is not a nuisance trip. That is a problem that must be protected from. And that is something that should not happen if other solutions are properly implemented.

This post has been edited by westom: Oct 22 2019, 11:23 PM

Wow, reply with 9 years old thread

And that current is microamps or less. Much of electricity flows outside the wire - the skin effect. Like the nearby lighting strike, it can create high voltages only when no current is flowing. ELCD/RCD is not about voltage. It is about current. That leakage may be in the microamp or nanoamp region. Well below what is normal leakage in electronics (powered off or on).


This post has been edited by westom: Oct 22 2019, 11:28 PM

Direct hit normally create very strong voltage, thus create high current surge as well. As you know sudden high voltage can also force high current flow. A strong lightning nearby can damage computer in a network, especially comm port. This was my own experience. There were many people around not to miss a direct hit, but no one could confirm if it was direct hit or not either.

A direct hit to an electrical pole at my house near the pole ground wire has caused part of the concrete pole to chipped and my house ELCB tripped. Luckily nothing damaged. No, as far as I know scientists have not really understood what caused this and that is different situation.

The skin effect where current flows more in wire core or more on wire surface is not not a concern at normal AC in house. The amount current flow is still the same. The skin effect become more concern at higher frequencies. At frequency even as low as 2.4GHz the cable can be hollow to counter power loss due to skin effect.

Skin effect is why AC power wires cannot carry any more current if thicker. And why voltage on one wire can create a voltage (with almost no current) on another. Skin effect applies to all frequencies down to but not including zero hertz. The point - skin effect explains why one wire can induce a voltage on another. And create maybe nanoamps of current - virtually a zero current.

So what is relevant? Leakage from wires is totally irrelevant - once we put numbers to that speculation. Most leakages are from appliances. Which is why some RCDs do not trip for a massive (less than) 5 milliamps. And why an RCD of 100 milliamps is massively above that normal leakage currents.

Described were some reasons for 'nuisance tripping'. In each case, due to some actual defect. For 'in the wall' wires to create nuisance tripping, insulation of two wires must be so massively compromised that wire separation is well less than 1 mm.

There are simple techniques for finding that defect. But the usual suspects are being ignored. ELCB/RCDs are almost last on a list of possible suspects. Tripping is reporting a defect.

Again, due to not having required solutions, then lightning (that did not trip that ELCB) creates a follow through current. We know a follow through current existed because that current is long enough to trip an ELCB. Lightning it not. Time is another parameter that must not be ignored.

We also know that comm ports are usually damaged not due to lightning on the communication lines. It is most often due to lightning incoming on AC mains. Then outgoing via comm lines. Damage is often on the outgoing path. A fact that get ignored if a conclusion is made only using observation.

A direct strike to all household appliances can be lightning striking poles many blocks away. But again, it is not the lightning that trips the ELCB. And that follow through current does not exist if appropriate solutions were implemented.

20,000 amps is too short to trip an ELCB. But the resulting 'follow-through' current created by that voltage means a large current that is longitudinal mode. Those type of currents easily trip ELCB/RCDs. 'Follow-through current does not exist if appropriate solutions were implemented.

Not sure what you were trying to say here. I know about skin effect not sure why you brought up the topic. As I mentioned before, the leakage seen in house wiring is not much a concern unless it is high.

You should tell TS how to know if ELCB/RCD defective since there are simple technique.

we dont used ELCB since 20 years ago. If your house still using ELCB then call your wireman.

https://en.wikipedia.org/wiki/Residual-current_device

The point of skin effect is overlooked. You said wires leak current. That that leakage can even be measured by 20 volts on a meter. That 20 volts is not leakage currents. It is an induced voltage created because current flows outside of a wire - skin effect. Current associated with that 'skin effect' created voltage is probably nanoamperes. Completely irrelevant to any ELCB/RCD operation.

Wires are not the typical source of microamp leakage currents. Appliances are. Even that resulting current is so low that a 5 ma RCDs should not trip. So a 100 ma RCD is well above what would cause an ELCB/RCD trip.

A 100 ma trip is saying that some defect existed. One example of why is 'follow through' current. Correct the reason for that current rather than blame induced currents by adjacent L-N wires. Replacing a 100 ma RCD with a 300 ma one is only to cure symptoms. Instead, address the actual problem.

I was referring the current produced by induced voltage by adjacent circuit as leakage current. That is not correct. It should not be called leakage current, but ghost current perhaps.

You were talking about the leakage current from appliance in circuit in OFF condition, which is quite common also and undeniable.

I'm not sure which article you read on skin effect though. For me, skin effect and induced voltage are two separate things. The induced voltage is the result of electrical and magnetic field. The skin effect is about where in the cross section of a conductor the current flow. That is one of the reason multi-core cable is used. The skin depth of a 50Hz copper electrical wire is about 9mm. The skin depth formula has nothing related to voltage as far as I know.

Skin effect is and because of E-M fields. Only pure DC stays inside copper wire. As frequency increase, more of the E-M field is outside that wire.. As noted, 2.4 Ghz has much more outside the wire. Skin effect or what induces on adjacent wires exists with any frequency as long as it is above zero. Skin effect is why AC electricity is typically only inside (if I remember the number) 9 mm inside a wire.

So yes, 20 volts is possible if two wires are together long enough and no current is conducted on the 'induced' wire. But once that wire starts conducting nanoamps, then that voltage drops to near zero. Nanoamps or even microamps are no where near relevant to a 100 ma ELCB/RCD. Numbers say move on to other suspects.

So what causes over 100 ma to trip that ELCB/RCD? Not just any current. It must be a longitudinal current. And it must be long enough for an ELCB/RCD to respond. A likely suspect is 'follow-through' current. It exists because that lightning current was all but invited inside. Creating temporary and conductive paths that permit a follow-through current (a longitudinal mode current) to exist long enough and strong enough to trip that ELCB/RCD.

Obviously replacing that circuit breaker or installing one with a higher rating would neither avert another trip or even address the problem. But again, this is only one suspect. A likely one that has been observed and eliminated elsewhere. And one not solved by so many other suggestions.

This post has been edited by westom: Oct 25 2019, 12:07 PM

Reply: for domestic use, 300mA cannot be used based on suruhanjaya tenaga.... for power circuit 30mA and light circuit 100mA.... if u dont have 2 diff circuit, then just go with 100mA.... never 300mA for house...

Hi, sorry to bring out the old post. I have same problem also, but is only happen when my surge protector connected to the wall socket, even its switched off. I need to unplug it to prevent the tripping. I have 2 surge protector, 1 bought at aeon don't know what brand that connected to the router, modem and nas, and another 1 is belkin. The aeon one is completely fine even a strong lightning strike. But belkin one cause the circuit breaker tripped even a very light lightning. Anyone know what is happening? Thank you.