RCBO or Ground Fault Interrupter Problem

[Retired2]

I have looked in this forum for this topic and cannot find my problem.

Enclosed, 2 photos of the Ground Fault Interrupter and the Distribution Unit itself.

With all the breakers open - no power to any circuit or to any line the Ground Fault (black) Bar will trip.

It does the same for all circuits or some of the circuits closed.

It may take 3 hours or 3 days but the bar will trip, cutting off all electricity.

Makes no difference if any combination is opened or closed.

I do not at all like the idea of turning the sensitivity selector to "Direct".

Any ideas on what I should do ?

By the way, I had a Thai electrician look at it and he said that maybe something was "in the air".

[Retired2]

Sorry that I am having problems with the photos.

[Crossy]

Look for a fault between Neutral and Earth (Ground), could be related to damp getting in somewhere.

Enjoy finding it, it will be a challenge.

[billphillips]

Something in the air !!! It's not as silly as it sounds. Equipment can attract power from electrical storms. Exposed cables are likewise. Microwave ovens often manage to leek power to earth and I once had an Electrolux washing machine that did the same. Water heaters are often suspect and are worth checking out. It's also worth remembering that the earth rod needs to be about 2m long and that the soil it's driven into should be permanently damp (ours is between two toilet tanks) so as to make a good contact, If the earth is anything less than 100% an earth leakage trip will not perform correctly. If your breaker keeps tripping out it may be now unserviceable because of simple wear, they are not designed for constant use. You should also check that your earth is not cross bonded to neutral, inside the distribution board.

[Crossy]

Good point Bill, if there's a N-E bond after the RCBO you're in for a world of hurt.

[bankruatsteve]

With mains power off, take the cover off all your plug receptacles and light switches. Chances are there will be gecko shit/eggs, ants, dust, or something in at least one of them. Use a vacuum and clean out everything. If that doesn't work, then chances are you have a "borrowed" neutral and, like Crossy says, good luck finding that.

[Retired2]

This is really good info that i am getting but Crossy,,,,,,,,,,,, I sure do not like the sounds of "world of hurt" ! ! !

[Forkinhades]

Intermittent faults are very tricky to find. Without the correct equipment you most certainly are pissing in the wind. If your safety device resets, then the fault has 'gone'. You need to try and find out exactly when said device opens, and ascertain what equipment is being used at the time, and whether you have ingress of water, or other nasties in your accessories.

Good Luck

[Pib]

Have you tried the sensitivity setting at a lower setting such as 20ma? Maybe the 30ma setting (if that is the upper setting...I can't make it out from the pictures) is defective/oversensitive. Maybe even rotate the sensitivity setting back and forth several times through it's complete range in case the switch is dirty/corroded.

[Retired2]

Have you tried the sensitivity setting at a lower setting such as 20ma? Maybe the 30ma setting (if that is the upper setting...I can't make it out from the pictures) is defective/oversensitive. Maybe even rotate the sensitivity setting back and forth several times through it's complete range in case the switch is dirty/corroded.

Thank you............. I have tried all the different settings. Same problem.

By leaving it to DIRECT am i losing all benefit of the interrupter ???

[Forkinhades]

^ You would want to set it higher, not lower

[Pib]

Have you tried the sensitivity setting at a lower setting such as 20ma? Maybe the 30ma setting (if that is the upper setting...I can't make it out from the pictures) is defective/oversensitive. Maybe even rotate the sensitivity setting back and forth several times through it's complete range in case the switch is dirty/corroded.

Thank you............. I have tried all the different settings. Same problem.

By leaving it to DIRECT am i losing all benefit of the interrupter ???

Yea, when setting it to Direct you have bypassed the RCBO/GFCI function....no protection.

[Pib]

^ You would want to set it higher, not lower

Where I said the 30ma setting may be defective/oversensitive is I mean if it's defective it may be tripping at a much lower level (oversensitive) than it's allowable limits for a 30ma RCD which would be 15ma to 30ma. Yes, the 20ma setting would have a limit of 10 to 20ma, but if the 30ma was defective/super sensitive, say 3ma,4ma, 5ma, just some low ma level, then it would be tripping very intermittently and probably frequently considering Thailand power/electrical standards/weather. But, he already tried the other settings so odds are it ain't a dirty sensitivity switch. Intermittent RCD tripping can be such a pain...I've been there...and I know I'm preaching to the choir.

[Retired2]

Weather keeps coming up.......... and it may be the only "common" clue.

It happens much more often with rainy days. We had 3 dry days here and it didn't trip once.

Now we have 2 days of rain and the thing trips quite constantly.

And yes, I have tried all the sensitivity settings.

[Forkinhades]

^ Yep thats your answer. Now you need to find the accessory that has the ingress of water.

[Pib]

Maybe a water pump which is maybe outside/gets rained on?

[Pib]

You might want to read the article at this Link which talks about RCD tripping being caused by factors "external" to your home....some partial quotes from the article below. Finding the reason for intermittent RCD tripping can be very frustrating sometimes.

..... the disturbance was caused by a set of streetlights being turned on. The waveform clearly shows the immediate load the discharged power factor correction capacitors placed on the source. This higher frequency disturbance was conducted from the Live, through the filter capacitors on hi-tech gear within the property, and through to Earth. According to the RCD this is, correctly so, seen as an earth leakage current and activated the trip.

The differential mode noise (simply the turning on of a significant load in an adjacent property), which would usually cause equal but opposing disturbances in the Live and Neutral and therefore cancel, is now found as equal and opposing disturbance across the Live and Earth.

This, therefore, presents a case where the Live and Neutral currents flowing through the RCD to Earth (via the filter capacitors) are not equal and opposing, and will be again be interpreted by the RCD as an earth leakage event. In this case the simplest cure is to employ an RCD that ensures the leakage is sustained before activating a trip (please note we do not state removing the RCD!).

This situation can be exacerbated with T-T, Z-T and I-T systems (see here) as the weaker earth systems can easily introduce noise and voltages into the RCD core in the form of unbalanced or common mode currents, especially in the presence of ground gradients (voltages that exist as a result of current flowing through the ground).

Such systems are extremely prone to RCD trips during lightning storms as a result of ground gradients even with cloud-to-could strikes (there is this weird thinking that only cloud-to-ground strikes cause ground voltages!).

But, it does not need a lightning storm; It could well be a neighbour with a problem causing an RCD to trip. If the neighbour has some Live-Earth fault causes voltage gradients in the surrounding earth mass, this is picked up by the T-T system's earth rod and transferred into the RCD as common-mode currents.

[billphillips]

You mentioned rain may be a cause of the problem, it's quite common here for electric men to make multiple splices or joints in cables and wrapping them in insulation tape. That would include cables that run underground to something like wall lights or water pumps etc. the effect of such a cable becoming wet could cause your problems. The only tape to use on a potentially wet join is amalgamating tape, even if it's inside a pvc conduit underground. Iv never seen an electric man that has any of this here, let alone one that uses it, it's quite expensive.

However I think the first and easiest check you should make is regarding any cross bonding from Earth to Neutral inside the consumer unit. Take off the cover and take / post a photo of the inside if you are unsure.

[Retired2]

OK.......... Now i am a little red faced. Partly from anger and partly from embarrassment. I have lived in this condo for 10 years and have been REPEATEDLY assured that there is a proper ground - earth.

Today, I demanded to see it with my own 2 eyes. The manager and engineer slowly told me that there is NO ground - earth wire. They do not see the need and will not install one.

You had better believe that I am going to get one installed before the week is up.

This may solve my original problem, right ??

[Crossy]

This may solve my original problem, right ??

Nope, it may actually make it worse, more chances for the 'lectric to go the wrong way.

You need to sort the issue with the RCBO tripping out before getting grounds installed. A man with an insulation tester and the knowledge of how to use it is your friend (good luck with that),

[Pib]

You don't need the safety ground/third wire for a RCD to work as a RCD is comparing the current flow in the Live/Hot wire with the Neutral wire....when the difference in current flow exceeds the RCD rating, say 30ma, then the RCD trips.

When a RCD trips it's because there was current flow to ground (i.e., like through your body to the floor, etc) from either the Live or Neutral wire causing the current flow to be different in the Live and Neutral wires thereby tripping the RCD. Having the safety ground may or may not change your intermittent tripping.

Also when you say no earth ground I guess you are saying your condo only has two-wire wiring (Live and Neutral; no third safety earth wire running to your power outlets) even though your outlet may have three holes "implying" three-wire use. Converting a residence from two wire to three wire would cost some money and not be an easy task since you are talking stringing wire through walls/replacing the wiring, possibly replacing outlet, and a variety of other modification. Two-wire wiring is still very common throughout Thailand.

[Retired2]

Well......... I am learning a lot.

Back to weather related causes........... I have an outlet (see photo) that is below a window that leaks water every time there is a rainstorm with wind. See the towel and mop

next to it ??

I took it apart - and it is very damp. I will disable this outlet.

Could this be the cause, even tho this circuit is open - no electricity to it from the central supply ?

[Retired2]

By the way............. In the first and second photo (above) that wire is from the True Visions satellite dish and is not related.

[Crossy]

That's certainly a prime suspect.

If you can disconnect BOTH wires that go to the damp outlet inside the distribution board or at the next outlet on the chain (insulate the ends) you may solve the problem.

At least then you'll know where the issue is.

[Pib]

That one picture showing the three prong outlet with only two wires (Live & Neutral) going to it with no 3rd safety ground is the perfect example of wiring that is typical in Thailand. Never assume a facility has three-wire wiring just because the outlets are three prong type.

[RichCor]

OK.......... Now i am a little red faced. Partly from anger and partly from embarrassment. I have lived in this condo for 10 years and have been REPEATEDLY assured that there is a proper ground - earth.

Today, I demanded to see it with my own 2 eyes. The manager and engineer slowly told me that there is NO ground - earth wire. They do not see the need and will not install one.

< snip >

So, where does the BLACK wire attached to your Earth-Ground BUS BAR go...

Just curious.

[Pib]

OK.......... Now i am a little red faced. Partly from anger and partly from embarrassment. I have lived in this condo for 10 years and have been REPEATEDLY assured that there is a proper ground - earth.

Today, I demanded to see it with my own 2 eyes. The manager and engineer slowly told me that there is NO ground - earth wire. They do not see the need and will not install one.

< snip >

So, where does the BLACK wire attached to your Earth-Ground BUS BAR go...

Just curious.

Yeap...although it's hard for me to be sure from the picture but it looks like a bunch of green wires (normally the earth ground wire color) running to the safety ground bus bar on the left hand side and then one black wire hooked to the ground bus bar heading back over towards the right side of the picture....maybe heading out to an earth ground?

[itsmylife]

check your air-con compressor first , disconect the air-con power and see will the power trip again or not.

Sent from my iPad Air2 using Tapatalk

[bankruatsteve]

OK.......... Now i am a little red faced. Partly from anger and partly from embarrassment. I have lived in this condo for 10 years and have been REPEATEDLY assured that there is a proper ground - earth.

Today, I demanded to see it with my own 2 eyes. The manager and engineer slowly told me that there is NO ground - earth wire. They do not see the need and will not install one.

< snip >

So, where does the BLACK wire attached to your Earth-Ground BUS BAR go...

Just curious.

Yeap...although it's hard for me to be sure from the picture but it looks like a bunch of green wires (normally the earth ground wire color) running to the safety ground bus bar on the left hand side and then one black wire hooked to the ground bus bar heading back over towards the right side of the picture....maybe heading out to an earth ground?

I only see a neutral bar in the photo. (?) If there's no ground wires then there wouldn't be any in the CU - yah?

[RichCor]

I only see a neutral bar in the photo. (?) If there's no ground wires then there wouldn't be any in the CU - yah?

The Green Wires tend to stand out. Looks like 4 (or 5) are running to the Ground Bus Bar mounted vertically in the box (extreme left of the photo).

A larger diameter Black Wire leaves the same Ground Bus Bar then snaked to the bottom of the box and up the right ...to where?

Unfortunate that it's Black (harder to trace visually).