Installing RCBO

[Anthony5]

My ex has a 6 million baht house with swimming pool, and as far as I can see there is no RCBO installed.

I worry a bit since I noticed that the pool pump sometimes fails to start, it will make a buzzing noise but doesn't start running. I'm afraid that at one point it will run hot and melts inside which would create a short and make the pool live. Is this possible?

I recall that I once had a small waterpump that was blocked and it tripped my RCBO when the capacitor melted.

So I would like to install an RCBO.

I had a look at the fuse box today, and it has 250A in RCB's and a main fuse of 50A. The new boyfriend told her there is a safety cut in the fuse box, but as I don't see the small push button on the main fuse I doubt it is one. All I see is that it is double the size of a RCB and has 2 thick wires go into it next to each other. It also has a double lever, probably to make it look impressive. I didn't take note of the brand but all fuses are black. The house has 3 wire system installed.

Could it be an RCBO without the small push button?

Now if I want to install one, do i just replace the main breaker with a 50A RCBO, or is there some rewiring necessary?

[RichCor]

"...and it has 250A in RCB's"

Not sure what this means.

Probably a good idea if you took a picture of what's there first. [Pic of CU (Breaker Box) both with cover ON and OFF]

Also get the brand name of the box, or main breaker, to see if they make a same-for-same RCD replacement.

A good test to see if a earth-ground leakage detection system exists is to try powering an incandescent bulb between Line and Earth-Ground. If an RCD is present it should trip the system immediately.

[Anthony5]

"...and it has 250A in RCB's"

Not sure what this means.

Probably a good idea if you took a picture of what's there first. [Pic of CU (Breaker Box) both with cover ON and OFF]

Also get the brand name of the box, or main breaker, to see if they make a same-for-same RCD replacement.

A good test to see if a earth-ground leakage detection system exists is to try powering an incandescent bulb between Line and Earth-Ground. If an RCD is present it should trip the system immediately.

Ooops, Should have read MCB's

Now what's the difference between an RCD and a RCBO? To me they look the same?

[Anthony5]

Ok, I have read up on RCD's and RCBO's, and am sure ( almost) that the 50A breakewr is an RCD.

So the question is if an RCD is sufficient in the situation I explain in the OP or should there be a RCBO in place.

[RichCor]

Some of your questions are covered in the ThaiVisa electrical forum pinned topics:

FAQ and useful documents

Started by Crossy, 2014-01-03 11:29

How to make your Thai Electrical system safe

Started by Forkinhades, 2014-01-02 14:35

How to check your earthing system

Started by Forkinhades, 2014-01-05 09:14

[Anthony5]

Some of your questions are covered in the ThaiVisa electrical forum pinned topics:

FAQ and useful documents

Started by Crossy, 2014-01-03 11:29

How to make your Thai Electrical system safe

Started by Forkinhades, 2014-01-02 14:35

How to check your earthing system

Started by Forkinhades, 2014-01-05 09:14

Ok, from Crossy's thread,

The dead give-away as to whether you have an earth leakage protective device is the presence of a 'Test' button, these devices need to be tested regularly to keep them functional.

So there is no RCD nor RCBO installed, since there is no no test button, and I will need an RCD.

I will tomorrow take a picture anyway, and at the same time test the earth values with my multimeter, because I understand in Thailand having an earth wire doesn't actually means it goes somewhere.

[Crossy]

I'll bet the box is Square-D or Schneider that takes plug-in MCBs and RCBOs, they are low-cost and find their way into many, many homes.

I'll also put money on the meter being a 15/45 which is OK on the 50A incomer. If it's never opened there's no real issue with 250A worth of MCBs. But do check the meter, it will be marked 5/15, 15/45 or 30/100.

If the box is Schneider / Square-D you need the QO245MBGX30 (45A / 30mA) on page 7 of this document http://static.schneider-electric.us/docs/Circuit%20Protection/Miniature%20Circuit%20Breakers/0739DB9901.pdf available in 16, 20, 32, 45 and 63A versions (all are 30mA leakage) this will be a direct replacement for the Square-D incomer.

The buzzing pool pump is another issue, possibly related to low supply voltage, you you have a multimeter?

[Anthony5]

I'll bet the box is Square-D or Schneider that takes plug-in MCBs and RCBOs, they are low-cost and find their way into many, many homes.

I'll also put money on the meter being a 15/45 which is OK on the 50A incomer. If it's never opened there's no real issue with 250A worth of MCBs. But do check the meter, it will be marked 5/15, 15/45 or 30/100.

If the box is Schneider / Square-D you need the QO245MBGX30 (45A / 30mA) on page 7 of this document http://static.schneider-electric.us/docs/Circuit%20Protection/Miniature%20Circuit%20Breakers/0739DB9901.pdf available in 16, 20, 32, 45 and 63A versions (all are 30mA leakage) this will be a direct replacement for the Square-D incomer.

The buzzing pool pump is another issue, possibly related to low supply voltage, you you have a multimeter?

Thanks I'll check it out this afternoon and will update tonight, but I think it is indeed squareD

Could I instead go for a 63A RCCB, or isn't that advisable?

The pool pump isn't really my problem, because I have advised the new BF long time ago, but he knows everything better. He claims that his mainbreaker is a safety cut, so let dumb people be dumb, I only try to protect the children.He also has a pool with 200ppm of CYA, but he says everything is fine. I have forbidden my son to swim in the pool.

The scenario of the pool pump making the pool live as I described in the OP, is that a possibility or is that exaggerated?

[Crossy]

Check out the meter rating. In reality a 63A front end is common on a 15/45 but won't get past the PEA initial inspection (I know), but if it's already a permanent supply there's no issue.

The pool pump going into meltdown is unlikely to cause anything shocking in the pool unless it's a very old installation with steel pipework, but it does really need RCD / RCBO protection.

[Anthony5]

I made it to the fuse box again today. The meter is indeed 15/45A, but I assume that can give more than 45A for short periods, right?

So therefor I wondered if using a 45A RCCD there would not be a risk of having it tripping to often, taken in account the amount of MCB's in the box.

So it is correct I need a RCCB, not a RCD or RCBO?

Going back to the pool, I see this small " thing" installed in the control box, and have no idea what it is.

Then regarding the pool getting live in case of a pump meltdown. The pipes are indeed uPvc, so they will not conduct, but the pumps are installed under the pool, so the pipes are always full of water.Doesn't that give the same risk as having steel pipes?

[RichCor]

Main Panel is Square-D.

Before Crossy answers, I just want to check, Anthony:are there any other live outlets, pole lighting, pool lighting, or any other circuits out near the wet area of the pool, (does no-one plugin a getto-blaster to listen to music)? These should all also be protected by an RCD type breaker.

[Anthony5]

Main Panel is Square-D.

Before Crossy answers, I just want to check, Anthony:are there any other live outlets, pole lighting, pool lighting, or any other circuits out near the wet area of the pool, (does no-one plugin a getto-blaster to listen to music)? These should all also be protected by an RCD type breaker.

The pool lights are LED, so 12V I assume. The outlets outside the house, which are at least 3 meters away from the pool, have a water proof/resistant cover.

There is only one fusebox in the house, so everything goes through that box, and I understood that the RCCB Crossy suggested would protect all at once.

Edit to add: If I look at that RT18-32X in the pool control box I see 380-500V.

So that means there is 3 phase in the control case?

[Crossy]

The Square-D unit marked as an RCCB is in fact an RCBO, it's just terminology. You would be OK dropping the 63A unit in as it's a permanent supply (already approved) the meter will be fine with the potential overload, many 15/45s are fused at 63A. Has the 50A incomer ever actually tripped?

The Akela unit is a simple fuse-holder so inside there should be a cartridge fuse, probably there to protect the control gear. The voltage and current markings are the maximum rating.

[Anthony5]

The Square-D unit marked as an RCCB is in fact an RCBO, it's just terminology. You would be OK dropping the 63A unit in as it's a permanent supply (already approved) the meter will be fine with the potential overload, many 15/45s are fused at 63A. Has the 50A incomer ever actually tripped?

The Akela unit is a simple fuse-holder so inside there should be a cartridge fuse, probably there to protect the control gear. The voltage and current markings are the maximum rating.

I asked and was told that the 50A never has tripped, but 45A is another 10% less.

Now the tricky thing will be to install the RCCB, because it will have to happen while live as to my knowledge there is no fuse between the meter and the fuse box.

[Crossy]

Now the tricky thing will be to install the RCCB, because it will have to happen while live as to my knowledge there is no fuse between the meter and the fuse box.

Since the square-D boards are metal cased there is a serious risk of the hot tails hitting the metalwork, absolutely not something you want to happen.

There is a lot of energy in the grid it won't be a little flash like you get if you short an outlet, there is serious risk of an arc flash which could cause serious injury or death.

I would NOT be doing this myself, get a local sparks to do it. He will likely pull the tails at the meter, make sure they're marked so he puts them back the right way round.

I've changed my incomer live a couple of times, but we have ABB plastic consumer units and it still scares me shitless.

[itsmylife]

@Anthony5 , change a new capacitor with same spec as the old one and try again , in most case is the capacitor problem come first that cause the power trip.

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[itsmylife]

@Anthony5 , and again the buzzing sound is from the worn out capacitor it just cant create enough power to start the pump so the buzzing sound came up . but be careful when u change the capacitor not to touch the terminal you will get shock too or death . im a air- con technician trust me .

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[Anthony5]

Now the tricky thing will be to install the RCCB, because it will have to happen while live as to my knowledge there is no fuse between the meter and the fuse box.

Since the square-D boards are metal cased there is a serious risk of the hot tails hitting the metalwork, absolutely not something you want to happen.

There is a lot of energy in the grid it won't be a little flash like you get if you short an outlet, there is serious risk of an arc flash which could cause serious injury or death.

I would NOT be doing this myself, get a local sparks to do it. He will likely pull the tails at the meter, make sure they're marked so he puts them back the right way round.

I've changed my incomer live a couple of times, but we have ABB plastic consumer units and it still scares me shitless.

I did the switch today the way you suggested, by disconnecting the tails at the meter, which was easy to do. I noticed now also that I had looked at the wrong meter and it is actually 30/100A.

The shop had only 63A RCBO from Schneider, and when asked what the difference with an RCCB, he told me that an RCCB doesn't protect against overload. Is that correct?

Small detail, I had disconnected only the two live wires at the meter, and when I tried to remove the main breaker I got a small shock. I then removed both outer wires at the meter as well, but realised that there is a solar water heater on the roof so opened that breaker also for all safety.

Did the shock come from the 2 outer wires still connected to the meter or from the solar water heater?

[RichCor]

Wish you had taken a picture.

When you wrote that you disconnected the two Live wires, do you mean L-in and L-out (L being the Phase Hot), leaving the Neutrals connected through the meter?

If Neutral isn't bonded to EarthGround anywhere nearby (as the uncertified Thai electricians like to do) then Neutral will carry potential across to EarthGround.

Always a good idea to pull/disconnect Live, then Neutral.

As a cautionary note, always check a circuit you with a DMM to verify a circuit you've disconnected is still not live. (L to N, L to EG, N to EG)

It's always possible someone before you has done something dangerously stupid and won't you be shockingly surprised when you find out.

Another possibility is that you got bit by a motor capacitor.

// Edited

[Anthony5]

Wish you had taken a picture.

When you wrote that you disconnected the two Live wires, do you mean L-in and L-out (L being the Phase Hot), leaving the Neutrals connected through the meter?

If Neutral isn't bonded to EarthGround anywhere nearby (as the uncertified Thai electricians like to do) then Neutral will carry potential across to EarthGround.

Always a good idea to pull/disconnect Live, then Neutral.

As a cautionary note, always check a circuit you with a DMM to verify a circuit you've disconnected is still not live. (L to N, L to EG, N to EG)

It's always possible someone before you has done something dangerously stupid and won't you be shockingly surprised when you find out.

Another possibility is that you got bit by a motor capacitor.

// Edited

At first I disconnected wire 2 and 3 of 4 wires, I had checked with a multimeter before and the 2 outer wires seemed to be neutrals, so I assume I indeed removed live in and live out.

I also noticed that the 2 left wires were aluminium, while the 2 right ones were copper, which of both will have been the wires going to the house?

After I had removed the 2 wires I also checked again at the fuse box, and there was no live anymore on the main breaker.

@crossy : You mentioned that I should watch that the wires were not switched when reconnected. What would have happened if I switched wire 3 and 4?

[Crossy]

Never assume anything when it comes to electricity.

Firstly should NOT have removed the incoming live, that was an extremely hazardous practice as it left a bare and live end with no overcurrent protection flapping around in the breeze, but all's well that ends well. For anyone else tempted to do this, remove both the outgoing leads having marked them as to which hole they came from. But my advice to get a local sparks to do this stands.

The Al incoming wires are pretty standard for Thailand, cheaper (a lot) and less likely to wander off in the night.

Swapping 3 & 4 (the L & N to the house) would have resulted in a L/N reverse, if the system is TT then mostly nothing would have happened except that your breakers and switches would have been in the neutral so every wire in the house would have been live and lethal even if turned 'off'. If you had a MEN link the resulting arc flash could have blinded you and / or taken your face off (don't even stop to think what would have happened if you were wearing contact lenses). And no, I'm not exaggerating, there is a reason that the guys who change meters in the UK wear face guards and gauntlets.

The units linked to earlier DO have overload protection despite being marked as RCCB (they are really RCBOs).