RCBO's, Individual Circuit RCBO's, and some questions.

[Thainesss]

So I have a very basic breaker box at my house. The box itself is earthed but all the circuits are 2-wire, and no RCBO. Never really cared much until I came back to find my wife has built a small fish pond using indoor pumps outdoors and installed the plug outlet about a foot above the waterline. So she stands in the water (thigh deep) and plugs/unplugs stuff while cleaning the tank & working... Just totally oblivious to the danger. 

 

So I need to make this safer because nobody else seems to care, or understand the danger. 

 

Im thinking about either installing a single main RCBO, or dishing out the money and swapping the consumer unit and all the breakers for individual circuit RCBO's. Im not really worried about the price. 

 

So my first question is this:

Reading back through the forum I saw a post from "Crossy" here he links to a DIN mount RCBO that can replace the main breaker in a consumer unit. (If I am reading this correctly, its rather confusing because I'm American and this all seems to be UK/Euro standard)

 

And looking around I found this on lazada which seems to be exactly what "Crossy" was linking to in that post, except its local cash on delivery:

 

https://www.lazada.co.th/products/rcbo-tomzn-40a-63a-ln-rcbo-ln-i154192286-s181622970.html?spm=a2o4m.searchlist.list.7.54774efbTkqzrr&search=1

 

 

Here is a picture of my breaker box:

 

 

 

So my First question is this - Can I swap the main breaker out for the 63A RCBO from lazada? This would save me from having to buy a new box as I dont have any more space, and the external safe-t-cut units are like 2,000 baht. This would be the cheapest & least hassle option in the short term. 

[Thainesss]

I really dont like the idea of the whole house tripping if theres a fault, so im debating buying individual circuit RCBO's and a new box with more space. The problem is that when the house was built, the 32a circuits were for Air/Water Heater/Pumps etc, 20a was plug outlets, and 16a was lighting. Since then my wife has added several additions to the house and the electricians piggy-backed off of existing circuits so nothing is exclusive anymore. (32a aircon breaker also controls some plugs in a new closet for example) So they all need to be RCBO to be truly safer. All this is very infuriating because when I tell my wife or the builders not to do things like this they think im being picky/dramatic. Nobody has any idea what im talking about. 

 

Im not going to re-wire the house but I am willing to change the breaker box and install all new RCBO's. I priced it today at about 9,500 baht for 10 RCBO's and a new 20-space ABB box. Thats not all that bad really, and the RCBO's fit with the correct orientation. 

 

So my question is this, can I use these (examples of what I found today from 3 different box stores) in 32, 20, and 16 amp/30ma? This is what Im looking for? 

 

 

And lastly, if im on the right track so far, is this British dude here explaining the installation if these units properly? Its a 12 minute video but the good part starts at about 5:30. If this guy is explaining it correctly, then I fully understand it. 

 

 

[Crossy]

No issue wiith either of your solutions.

 

A front end RCBO is (should be) easy.

 

Your biggest problem with using individual RCBOs is going to be "borrowed neutrals" where one neutral is shared by more than on circuit, you could well end up with RCBOs that won't stay on and have to combine several existing circuits on to one breaker. Not really an issue unless both circuits are high power (kitchen).

 

Also, I would only protect "hazardous" circuits with RCBOs, wet rooms, outdoor outlets and lighting, fish pond!!, water heaters. No real need to bother with your indoor lighting, aircon and the like (although the aircon really should be earthed). Certainly leave an unprotected circuit for your freezer.

 

EDIT Since you have a potentially lethal situation, I would go out TODAY and buy one of the individual RCBOs that have their own box. All the big box places have them, around 500 Baht.

[Thainesss]

15 minutes ago, Crossy said:

A front end RCBO is (should be) easy.

 

So just to confirm, that RCBO I linked to from lazada will work as a direct main breaker replacement? Main reason im concerned about it is the price - its only 340 baht lol. Every RCBO ive looked at here range from 5,000 baht to like 2,000 baht so im a little skeptical, and wondering why these arent more widely used considering the price/space/etc..

 

19 minutes ago, Crossy said:

Your biggest problem with using individual RCBOs is going to be "borrowed neutrals" where one neutral is shared by more than on circuit, you could well end up with RCBOs that won't stay on and have to combine several existing circuits on to one breaker.

 

Is there any simple-ish way to check for this at the breaker box? I have a DVOM and Inductive amp clamp.

[Crossy]

URGENT EDIT  Whilst the Lazada unit looks OK from the diagram in the unit, the spec says it's 1P+N suggesting that the neutral isn't switched. This isn't right for an incoming breaker. For only 340 Baht it's worth getting anyway and verifying if the neutral is switched, if it is great, if it's not you can still use it, but it must be between your existing main breaker and the rest of the board.

 

Finding borrowed neutrals is a right-royal pain. An easy (but not foolproof) check is simply to count the number of lives leaving the box and the number of neutral returning to it. They should be the same. That should give you an idea just how big a problem you have.

 

Task A, is to identify which neutrals go with which breaker and label them. Use your meter and a long traily lead to the neutral at a point controlled by the breaker you're interested in. With all the neutrals disconnected from the neutral bar find the one that's zero ohms and mark it. Rinse and repeat for the other breakers. This should also show up any borrowed neutrals (one neutral from two breakers).

 

Power Off of course!

[Crossy]

@Thainess please check my edit in post #5

 

EDIT Should be Thainesss

[Thainesss]

10 minutes ago, Crossy said:

if it's not you can still use it, but it must be between your existing main breaker and the rest of the board.

 

That would mean that its simply an RCD and not an RCBO correct? 

[Thainesss]

17 minutes ago, Crossy said:

his isn't right for an incoming breaker. For only 340 Baht it's worth getting anyway and verifying if the neutral is switched

 

I can just check the resistance of the Neutral side with the breaker switch in both positions to confirm that the device is actually switching both sides to confirm this, right?

[Crossy]

It's actually more fun. I've found so photos of the Tomzn unit in bits, it LOOKS like it has two contacts which would be perfect.

 

The RCD mechanism, note the contact on the left.

 

 

The MCB (over-current) section, it too has a contact.

 

 

Photos from here https://www.aliexpress.com/item/DPNL-1P-N-63A-230V-50HZ-60HZ-Residual-current-Circuit-breaker-with-over-current-protection-RCBO/1086847618.html

 

 

[Crossy]

1 minute ago, Thainesss said:

 

I can just check the resistance of the Neutral side with the breaker switch in both positions to confirm that the device is actually switching both sides to confirm this, right?

Yup.

[Thainesss]

7 minutes ago, Crossy said:

It's actually more fun. I've found so photos of the Tomzn unit in bits, it LOOKS like it has two contacts which would be perfect.

 

Good because I ordered 3 just in case lol 

 

31 minutes ago, Crossy said:

Task A, is to identify which neutrals go with which breaker and label them.

 

Easy enough. There are the same amount of line and neutral wires entering the box, and the wires are still encased in the romex covering and "paired" together by it. 

 

33 minutes ago, Crossy said:

Use your meter and a long traily lead to the neutral at a point controlled by the breaker you're interested in. With all the neutrals disconnected from the neutral bar find the one that's zero ohms and mark it. Rinse and repeat for the other breakers. This should also show up any borrowed neutrals (one neutral from two breakers).

 

Im struggling here. Can you explain this a little more specifically? Like place one probe (location) and the other probe (location) so I can understand what im checking the resistance of? 

[Crossy]

2 minutes ago, Thainesss said:

Easy enough. There are the same amount of line and neutral wires entering the box, and the wires are still encased in the romex covering and "paired" together by it.

Excellent! You are probably good to go. I'd bang in some individual RCBOs and assume (I know, I know) that the L and N in each jacket are the same circuit. If one RCBO won't stay on then see below. 

 

2 minutes ago, Thainesss said:

Im struggling here. Can you explain this a little more specifically? Like place one probe (location) and the other probe (location) so I can understand what im checking the resistance of? 

OK. Let me try to be clearer, it's early in the morning and my explaining head is in the laundry.

• Power Off.
• All neutrals disconnected from the neutral bar.
• Go to somewhere on the circuit you are interested in (say an outlet).
• 1 meter probe on the neutral at the outlet.
• Back at the breaker box (which is why you need a long lead), the other meter probe on each neutral in turn until you find the short, that's the neutral from the outlet.
• Mark this wire, and go to another circuit.

 

 

[Thainesss]

20 minutes ago, Crossy said:

OK. Let me try to be clearer, it's early in the morning and my explaining head is in the laundry.

 

Meh my head is always in the laundry lol. Thanks man!

[johng]

If your switches,  breakers or RCBO's  stop working check for Ants !!!!!

 

A quick simple fix for @Thainessswould be to wire one of these

before the  outside plug outlet (just the one  L and N + E wire that goto that socket)

to keep things safe (er) while you work out a more comprehensive solution.

[Thainesss]

Another question - Im leaning towards buying a new consumer unit, and I am thinking about adding a volt/amp digital meter to it. 

 

Something like this DIN mount one:

 

 

Specifications:
Model: D52-2048
Installation: Din-Rail
Material: Plastic, Electronic Component
Display: 0.31-inch Red LED 4-digit tube
Measuring Voltage: AC 80-300V
Measuring Current: AC 0-100A
Measuring Active Power: AC 0-30000W
Measuring Apparent Power: AC 0-30000VA
Measuring Power Factor(cos ø): 1.000-0.000
Accuracy: 1%
Measuring Speed: 2 Times Per Second
Operating Temperature: -20°C ~ +50°C
Size: 80 x 54 x 64mm / 3.1" x 2.1" x 2.5"

 

https://www.lazada.co.th/-i100408617-s100470139.html?urlFlag=true&mp=1

 

My question is on the wiring of it. 

 

I can see that it has a built in transformer to measure the amperage, and separate contacts to measure voltage. Similar to an inductive clamp. 

 

Can I wire it like this- 

 

Basically jumper from the main to the small contacts for voltage, and run the mains line power through the little transformer hole to the first RCBO or Breaker, then use the BUS bar to the rest of the breakers? The HaCO RCBO's have connection ports for both wired and BUS connection. 

[Crossy]

8 minutes ago, Thainesss said:

Basically jumper from the main to the small contacts for voltage, and run the mains line power through the little transformer hole to the first RCBO or Breaker, then use the BUS bar to the rest of the breakers? The HaCO RCBO's have connection ports for both wired and BUS connection. 

Yup, pretty much.

Wire the voltage sense so something with overload protection (lighting circuit) or use an in-line fuse. Poke the fat live (or neutral if easier) through the hole.

 

Do note that I've had two of these units (ok mine looked the same), both failed after a while with random readings. Ditched for nice simple analog meters (and one of those sticks).

 

In the end I made my own.

 

 

[Thainesss]

14 minutes ago, johng said:

If your switches,  breakers or RCBO's  stop working check for Ants !!!!!

 

I recently had the same problem with a light switch. I guess the ants are attracted to the frequency of the electronics. 

 

15 minutes ago, johng said:

before the  outside plug outlet (just the one  L and N + E wire that goto that socket)

to keep things safe (er) while you work out a more comprehensive solution.

 

Ive banned the wife from being a dumbass for the time being (not sure how long that will last) until I get it all sorted. 

[Thainesss]

12 minutes ago, Crossy said:

Poke the fat live (or neutral if easier) through the hole.

 

Didnt think of that. That would be alot easier!

 

13 minutes ago, Crossy said:

In the end I made my own.

 

If I was a millionaire id get a stack of these & go mad scientist with some solar panels:

 

https://www.tesla.com/powerwall?redirect=no

 

 

[Thainesss]

Last question for now. 

 

The box is apparently earthed, but I don't know where the ground rod/connection is. 

 

The ground/earth bar only has a single green wire connected to it, and then out into the wall somewhere. There is no wire going from neutral bar to earth bar. 

 

If I put my volt meter across from line power to the earth bar I get full voltage. 

 

Is this a good indicator that the earth bar is actually earthed/grounded?

[Crossy]

2 minutes ago, Thainesss said:

Is this a good indicator that the earth bar is actually earthed/grounded?

Not really.

 

In the absence of a proper earth resistance meter try this:-

• Disconnect the rod wire from the earth bar.
• Connect a small (15W) incandescent ligh bulb to the rod wire.
• Connect the other end of the light bulb to your live.
• Turn on the breaker.
• Observe the lamp, bright light = good earth.

Not ideal, but will give some idea.

 

You could measure the voltage across the lamp and guesstimate the actual value of earth resistance.

 

[Thainesss]

3 minutes ago, Crossy said:

Not ideal, but will give some idea.

 

Thanks!

 

Ok I lied, not last question - one more:

 

all of the individual RCBO's have small earth sensor wires. 

 

My box is earthed (maybe) but none of the circuits are. 

 

Any benefit to connecting the RCBO earth wire to the earth bar? 

[Crossy]

10 minutes ago, Thainesss said:

Any benefit to connecting the RCBO earth wire to the earth bar? 

Yes. If it has a "functional earth" (not all do) connect it.

 

It helps the RCBO detect N-E faults. Less of a hazard than L-E faults but nice to find.

 

[Thainesss]

On 1/9/2019 at 7:39 AM, Crossy said:

URGENT EDIT  Whilst the Lazada unit looks OK from the diagram in the unit, the spec says it's 1P+N suggesting that the neutral isn't switched. This isn't right for an incoming breaker. For only 340 Baht it's worth getting anyway and verifying if the neutral is switched, if it is great, if it's not you can still use it, but it must be between your existing main breaker and the rest of the board.

 

So these came today and I checked the switch - Both sides are switched. 

 

Im not going to use them, Im gonna change my box and use individual RCBO's but I just want to confirm that this is good to go to swap a main 63a breaker with this as a safe-t-cut device because I might give them to friends. 

 

Good to go?

 

 

Edited January 12, 2019 by Thainesss

[Crossy]

10 minutes ago, Thainesss said:

So these came today and I checked the switch - Both sides are switched. 

Excellent, that's really good to know, the price is right too.

 

16 minutes ago, Thainesss said:

Good to go?

The 4kA breaking capacitiy is a bit low for a main switch, but unless they're right next to a big transformer I doubt there will be any issues. It has to be better than no earth leakage protection.

[Thainesss]

Just about have everything ready now. Just wish I could have found a taller box with a bunch of ways. Ill be trimming the line and ground leads from the RCBO's to fit & using zip ties to make it clean. Tomorrow a guy is coming to install a mains power switch at the pole by the meter for me so I can get everything isolated. 

 

Question 1 - since im having to use different brands of breakers & RCBO's, they are all a different overall size, so the busbar that goes at the bottom doest quite fit. 

 

Whats the procedure here? Bend the busbar a little? Shove it in there with my thumb and tighten the screw (seems not good)? Scrap the busbar and wire it? If so, what size wire? (Im leaning towards scrapping the busbar and wiring it)

 

Question 2 - Im planning on running the Neutral wire from the main power breaker, around the bottom of the box and up through the amp meter transformer and into the neutral bar. Ill take a voltage signal from a 16a lighting RCBO. Ill use 2.5 sq. mm wire for the voltage signal (its on hand) and use 16 sq. mm wire for the neutral through the transformer to the neutral bar (25 sq. mm wont fit). 

 

Am I close to the mark here for the volt/amp meter? 

 

The following pics is how im thinking of arranging everything in the box (aside from the busbar at the bottom, thats a visual of the problem). 

 

Please let me know if you see anything wrong/have a suggestion. 

 

 

 

 

[bankruatsteve]

Frankly, I don't see anything that looks right.  No ground?  Why are all the wires going over the edge of the box?  Din rail?  Then why would you have to bend anything?  Expect Crossy can sort you out.

Edited January 12, 2019 by bankruatsteve

[Wirejerker]

Use the bus and cut it at the change of levels and use wire bridges between the levels. I would leave a gap of one or two poles next to the 32A CBs for future upgrade. You can fill the gap for now with a CB from the old board


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[Thainesss]

51 minutes ago, bankruatsteve said:

Frankly, I don't see anything that looks right.  No ground?  Why are all the wires going over the edge of the box?  Din rail?  Then why would you have to bend anything?  Expect Crossy can sort you out.

 

The box is simply sitting on my desk mocked up, not on the wall like that. 

 

Not sure what you're looking at? Are you thinking it's screwed into the wall like that? Do screwdrivers and side cutters adhere to walls when not in use?

[bankruatsteve]

2 minutes ago, Thainesss said:

 

The box is simply sitting on my desk mocked up, not on the wall like that. 

 

Not sure what you're looking at? Are you thinking it's screwed into the wall like that? Do screwdrivers and side cutters adhere to walls when not in use?

My bad.  Sorry.

[Thainesss]

15 minutes ago, Wirejerker said:

Use the bus and cut it at the change of levels and use wire bridges between the levels. I would leave a gap of one or two poles next to the 32A CBs for future upgrade. You can fill the gap for now with a CB from the old board

So a wire bridge would basically be a jumper between the level changes, right? What size wire?