Safety Switch tripping...

[samuijimmy]

I just moved into a brand new house, about 10 days ago.. generally speaking the wiring seems to be better than most houses in Thailand ... even grounded outlets

But three times now (twice today) with only the telly and refrigerator running the safety switch tripped, turning off all power! They are not on the same fuses....

Question! I see on the safety switch that it runs between 6 and 30 (not sure what that is ?) Can this just be turned to say 20, and would that help? Would wiring inside the box need moving or can one just turn the switch?

Houses next to mine, are the same build, but not losing power!

Not too technical answers appreciated!

sorry image a little blurred!

[aussiandrew]

Go and have look at the settings at your neighbors board if theirs are not tripping.

[sandmike]

SJ, the numbers are thousandths of an amp (milliamps). You can safely turn the RCBO up to 30mA with no safety issues (unless you've got a heart problem) a lower setting is a good idea if there are small children around. If it's still tripping at the 30mA setting then there is a more serious problem. The RCBO monitors the whole house power supply, so it sees everything in the house. You could try unplugging the TV and fridge in turn for an hour or so and see if the problem repeats. Do you have an electric shower heater ??

[Crossy]

+1 on Sandmike's response, no problem setting it to up to 30mA.

If you get tripping then call your sparks, although it really shouldn't be opening even at 10mA.

Have you had rain recently? May be the damp has gotten into outside lighting or outlets.

[samuijimmy]

Thanks, Crossy and Sandmike!

Yes, lots of squally rain the few days before... perhaps one of the outside plugs or lights causing problems ... ?

Will try upping to 30 and see what happens... I am going to up the size of the ground wire too..it looks to small...

[lopburi3]

Outside runs can be a real issue - electric door bells are often a problem here as run direct 220v AC and very dangerous. These and outside lights/outlets/pumps can easily total tripping fault on such units at times. That unit is a life saver so it trips very quickly when a fault is detected - but it is worth the effort to find and correct issues as it can you your life it saves.

[gandalf12]

First of all the photo shows Circuit breakers not fuses. Circuit breakers trip faster than fuses which is good. I would set it to 20 which is mA and it should be ok. It is probably picking up some leakage current. I wouldnt set it higher. If it still trips you need the wiring testing.

[MockingJay]

ASK THE ELECTRICIAN!!!!! man....

[stoneyboy]

ASK THE ELECTRICIAN!!!!! man....

The ELECTRICIAN has spoken,I believe Crossy knows exactly what he's talking about as do a whole host of other regulars.

[Crossy]

ASK THE ELECTRICIAN!!!!! man....

Whilst finding a half decent domestic sparks here can be a nightmare, it's a brand new house, so definitely worth talking to the developer's sparks.

[SiSePuede419]

"It is probably picking up some leakage current."

A short?

Or a ground fault (caused by improper grounding)?

Just because they have an Earth ground on the outlets doesn't mean everything was wired properly.

Do you have an voltmeter? I'd check to see if its properly grounded first before fiddling around at the control box (they're recommend ing changing the ground fault trip current (leakage/short) level. That shouldn't be needed if the wiring was done properly.

I wired my own house. AC & DC. Solar panels & Wind. You don't run AC outdoors, unless you know how to do it right, otherwise big mistake.

Low Voltage 12V DC or even solar is the way to go for garden/landscaping lighting 555

[Crossy]

Random tripping of RCDs / RCBOs can be a nightmare to diagnose.

First stop, power off and pop off any outdoor outlets, switches and lights. Any that look a bit damp can be left open to dry out, of course you could turn the juice back on and use Wifey's hair dryer.

If it's nothing immediately obvious a neutral-earth short can cause odd effects although trips are normally associated with heavy loads being turned on.

By the way. An off-topic post has been removed.

[Crossy]

Another off-topic post has been removed.

Please take the subject to support[at]thaivisa.com ensuring you quote supporting legislation.

Obviously Thai language will be fine.

[Neocon]

Previous residential CU was a Safe-T-Cut RCBO with a correct size main breaker and correctly earthed - watched the install. One day main breaker started tripping; every few hours at first, then every 7 mins on the spot - had to wait 10 mins before being able to reset - likely an overheat problem. Turned off main breaker and left it off - rang reliable local sparky.

Before sparky did his troubleshooting I tried different RCBO settings; turned off all individual breakers and turned on one by one; unplugged and re-plugged all electronic items. Sparky determined it was a faulty main breaker. Changed to an ABB CU - no problems now for 9 months. I haven't bothered with contacting Safe-T-Cut.

Thank you to Crossy and others - your knowledge and wisdom over the years have greatly helped.

[Jing Joe]

Don't like the fact it is tripping on you. Even 6 M/a of shock under other future protective fault conditions you may have however brief aint nice.

The earth wire doesn't need to be huge in your case. Just multi stranded so it wont flex and break and will carry 30m/a trip minimum.

Many heating devices can leak when they are on. e.g.;- Iron, shower water heater, clothes dryer, hot water system, ballast transformers in florescent lights, Low voltage transformers in halogen lights. Pumps, I.R. sensor lights, door bell as someone said, touch sensitive bed lamps, the anti-dew heating elements in the fridge shell, etc.

Even if a device is not actually running and the wall switch is off, and IF they have by mistake wired the active wire to the neutral in the back of the socket and that device does have some leakage, then the unbalance at the leakage detector will trip it.

If you look at the simple circuit on your RCBO, the L and N leads have a pickup wire circled around them and senses if the currents are equal. If they are not equal being opposite in direction, by as little as 6 Milli-amps, the other little box in that circuit will trip the contacts. They are not equal when some of the return path is via earth and/or you.

If you can isolate the tripping to one device, good.

If its the TV at fault and its lead only has two wires, no earth, maybe there's leakage getting back through the aerial coax that might be earthing at the other end on the roof or is there a aerial splitter/signal booster amp in that coax cable? Unplug the aerial cable with caution.

If its the TV and you are using the RCA sockets or HDMi leads to connect to the DVD etc and if one of those has a 3 wire power cord, then there's a possible earth path from the TV to trip. The quality of some TV's I see is questionable.

If you isolate absolutely everything and it still trips (give it a while to happen) then like others have said; look for wet wiring either in u/ground, power wall outlets or concealed junction boxes.

If the wiring passed the usual insulation test (and all sockets wiring) at its completion ,, an insulation fault should have shown up then, but maybe not if water has got in since.

A test should also have been done using a long lead to check the continuity from the earth on the sockets to the outside earth stake. They should have checked your earth stake resistance to ground, using another test earth stake driven in not too far away. Damp ground near your stake is better than bone dry.

Seems like your earth connections are OK anyway because it is tripping.

Always good to make sure of good earth connection to the copper plated (?) earth stake. Don't disconnect to do a better job with the main power contactor still on.

That should be a sparkies job anyway. If that's not broke, don't try to fix it.

Good advice from others also should help you keep an eye on a sparkie anyway??

[Jing Joe]

RE; (Don't disconnect to do a better job with the main power contactor still on.)

Sorry; my mistake. I meant to say main power circuit breaker. And/or purposely trip the RCBO test button.

But still; don't touch Sparkie's job stuff.

[Pdavies99]

Having the safety switch set at 6 is great, but super sensitive, in my house unplugging anything roughly or unscrewing a light bulb will set off my safety switch at 6.

As others mention adjust the setting to say 10 or higher and see if its okay.

[Snackbar]

Safety cut is illegal in regulated countries. An unqualified person can meddle with it. Average Thai 'electrican' will simple turn it off... Problem solved. Clearly not the case.

They are illegal for good reason.

[Crossy]

Safety cut is illegal in regulated countries. An unqualified person can meddle with it. Average Thai 'electrican' will simple turn it off... Problem solved. Clearly not the case.

They are illegal for good reason.

So what would you install instead?

And how would it address our OPs issue?

Name a country where it would be illegal and cite the regulation in question.

EDIT I assume that it would be the adjustable trip current that you are referring to as 'illegal', I'm not aware of anywhere where RCBOs per-sé are not permitted. Note that the modern units (our OPs included) do not appear to have a 'bypass' or 'direct' mode and so cannot be turned 'off'.

[bankruatsteve]

An RCBO (as in front-end) just wouldn't work in most US homes. But, the "GFI" is required by USEC at point of use in certain areas (bath, outside, etc.)

[Crossy]

An RCBO (as in front-end) just wouldn't work in most US homes. But, the "GFI" is required by USEC at point of use in certain areas (bath, outside, etc.)

Actually, you could probably install a 4-pole RCBO (use 2 phases and the neutral) as a front end on a US split-phase system.

Not something I've tried mind but I see no reason why it shouldn't work and provide leakage protection.

However, we have drifted off-topic, back to our OPs issue of his Safe-T-Cut tripping when it shouldn't (or should but he doesn't know it yet).

[jhonnie]

RCDs monitor current flowing between active and neutral legs of a circuit. If there is an imbalance of 6/10/20/30 milli amps the circuit breaker is then designed to trip. These imbalances occur when poorly insulated appliances or electrical circuits leak a little current to earth; or in the case of electrocution, leak current through a human being who has been connected to earth through a faulty appliance or circuit fault. Generally the protective trip time is rated in milliseconds which is faster than a human heart beat. The purpose of this instantaneous trip is to cut the power before it can cause a heart to go into ventricular fibrillation, which is the uneven beating of the heart and can occur when fault currents exceed 75 milli amps.If this happens to you, you will still be alive but probably only 3 minutes away from being brain dead as there is no blood circulating in your body.

Bear in mind that an RCD will not save you if you inadvertently are connected to a circuit without an earth or even to a circuit that is earthed but where there is no means for the fault current to flow to earth. When the current flows through an individual and back into the mains supply it is a different story altogether. Be prepared to be burnt, thrown across the room and/ or unfortunately killed.By the time a 20 amp circuit breaker trips its more than likely all over red rover!

Old fridges used to be a common culprit and in the early days it was recommended( to save the electrician a call out ?) to put them on a separate circuit. Go figure! An electrician with a mega meter can test the insulation resistance of various appliances, circuits and sub circuits and rectify any insulation problems.

[Snackbar]

I don't have a copy of the 17th edition, IET BS 7671 wiring regs handy.

Nor do I have the inclination to copy and paste the relevant regulation for your satisfaction.

I do however know that any accessible 240v socket outlet must be protected by a designated RCD.

A safety-cut is not such a device.

[sandmike]

^

A safe t cut is an adjustable RCD protecting the whole house.

In the UK there is a single 30mA RCD protecting all socket outlet circuits, and a 300 mA RCD protecting fixed circuits.

How is this different ??

[Crossy]

A safety-cut is not such a device.

So what is it then?

It has nice big letters saying "RCBO" on the front.

It may not be UK approved by virtue of its being adjustable, but it's still an RCD / RCBO and it could be argued that it offers greater safety by virtue of it being able to be set to <30mA as against the fixed 30mA units prevalent in the UK.

I DO have my copy of the 17th, so I'll have a search for you

[Snackbar]

It's not an individual circuit device, it's adjustable and more often than not overridden.

It's popularity comes from a plastic electrican's opportunity to charge a large amount of money for practically nothing.

That's why they are illegal in regulated countries.

[JAS21]

Snackbar, on 30 Jan 2016 - 17:39, said:Snackbar, on 30 Jan 2016 - 17:39, said:

It's not an individual circuit device, it's adjustable and more often than not overridden.

It's popularity comes from a plastic electrican's opportunity to charge a large amount of money for practically nothing.

That's why they are illegal in regulated countries.

Here Snackbar

Mine isn't ... nor is my neighbours ...nor are any of my friends ...

anyway ...

I've looked through a few of your posts and find you pretty anti ...this particular forum has some very qualified people giving excellent advice. To be perfectly honest if you want to be critical then you need to be right else you make yourself look, I suppose a polite description is 'unwise'.

I don't recall and have not been able to find what you quote about the 17h Regs. I do however know that they are proscriptive as apposed to prescriptive ... if you don't know what that means may I suggest google.

enjoy .... a few more chang

[Crossy]

Ok, a quick troll through the 17th.

The best I can manage is that is almost certainly doesn't meet any of the UK or Harmonised Standards in Appendix 1 - but only because it's not been tested to them.

We still have the get-out of Reg 511 which allows you, as the designer, to confirm that the equipment provides the same degree of protection that would be afforded by compliance of the regulations (but your head is on the block if someone dies). I'm not going to put one in the UK, plenty of approved devices to do the job.

Of course we already have adjustable devices in use with Insulation Monitoring Devices and MCCBs with adjustable earth fault protection although these are unlikely to be found in any normal domestic installation.

Nowhere in the 17th does it state that the RCD must be an "individual circuit device" whatever that is. A normal "17th Edition" CU will have a main switch and 2 RCDs, the idea being to split power and lighting between the two sides of the board, so a single earth fault doesn't take out all the power or lighting.

[Snackbar]

What I do know is the electrical installation industry isn't regulated. 'Electricians' are not registered. New installations are not tested. A non Thai is prohibited from carrying out any electrical work. Of course you knew that already. And safety-cut devices are more often than not over ridden. Which you didn't know.

Unskilled and innocent victims are injured or killed daily in Thailand as a consequence. A simple search may enlighten you.

The only advice given here must be to contact an approved contractor.

[Crossy]

Oh, I agree with much that you say. It's just the confrontational "I know best" attitude, your input, when relevant and directed is more than welcome.

I also agree that the beasts are heavily over-priced, a quality ABB RCD in a little box will give the same protection at about 25% of the cost, but it's not 'plug-and-play' like the flashy Safe-T-Cut..

Why do you say I don't know that Sate-T-cuts are often over-ridden? The original models did indeed have a 'direct' mode which totally negated the point of having one, it looks like it's been removed form the latest units.

The only advice given here must be to contact an approved contractor.

EDIT I would dearly love to give this advice to every query, this forum would no longer be needed.

BUT. Can you name even one?

It's not going to happen

Directed and informed DIY is far better than Somchai with his tape, scissors, neon and hammer, coupled with zero knowledge of what he's doing.