electricity meter and CB, please settle

[ilikethai]

I'm not an electrician but the local pros are many times wrong.  Anyway, did a 9 hr travel to a friend's place and trying to help with his rewire for his house and a small shop but instead we decided to hire a local.  got into a heated argument with a "pro" electrician.  Anyway here is the current house set up and the pro said it's fine and wouldn't want to redo it:

3/9 meter 220v---> av25 7s/1.7mm 0.6/1kv (assuming this is the size?) black aluminum wire------->connected to a metal clamp and into a copper 4mm size------->into Voltage stabilizer with 50a builtin breaker, earthed----------> then out into 2.5mm copper size into a 60a MCB black very old looking square breaker-------> out to 2 sockets (outlets) 1.5mm wire size combine with 4 lights--------> (from 60a MCB) 2.5mm wire to kitchen socket and 2 pairs of lights (1 switch control 2 lights)--------->(from 60a MCB) 2.5mm wire to 30a CB dedicated for water heater then it taps out into another 30a CB for the fridge and sockets------->(from 60a MCB) to 30a with 2.5mm copper wire into a socket combined with 3 lights then taps out into another 30a with 1.5mm (yes) copper wire solely for AC 10,000btu

 

the shop:

5/15 meter 220v ------>straight from the meter with 2.5mm copper wire into 30a CB for 4 lights low wattage, 1 fan, 1 socket------>tap out to 30a CB with 2.5mm copper wire for 4 lights, 1 fan, 1 socket------>straight from meter with 4mm copper wire into 30a CB for a med size 2 doors beverage showcase cooler (it says 5.6amp on the inside spec sticker but I don't think it's that much or I'm wrong) and earthed the cooler with copper rod with 2.5mm copper wire.

 

Also he demanded that the L and the N wire must pass through the MCB and the same into all the small CB's L and N slots.  Should it be better if  L and N wire from meter all go into both of the MCB slots first, then from MCB out divert the N wire into a dedicated bus bar in the distribution box and all the CB's N wires into the same bus bar?  Does it matter?

 

if the meter says 5/15 220v would it be better to match it with a 15a breaker or even a 20a breaker instead of a whopping 60a breaker?

 

Is ELCB breaker a must to be put between the MCB and the smaller CB's?  Or should this ELCB breaker be put between the meter and the MCB?

 

Sorry very confusing. Thankful in advance

[sometimewoodworker]

Your explanation of the setup looks as if there is some kind of code involved so is horribly difficult to understand, your abbreviations are not standard.

 

However yes the in coming  main breaker should be lower than 60A

 

I couldn't workout the sizes of the in coming wires and the breaker should match them, the meter will probably supply at least 30A without problems, but will not be accurate.

 

 

 

[Crossy]

I think we are going to need some photos here.

 

Small breakers with L and N connections could well be RCBOs in which case they will need both L and N feeds.

 

A 5/15 should be fine with a main breaker of 30A, anything larger after that is not relevant. 

 

 

 

[Crossy]

This PEA document could be useful. Groundwire Mk2 book-Manual.pdf

 

And a handy translation of the important bit.

 

[ilikethai]

thanks for the fast reply.  Let's just say #1 meter is 3/9 how would I go from here, it needs to power 10,000 btu AC, water heater, small electric cooker, rice cooker, about 12 lights, 5 sockets?

 

#2 meter is 5/15 and how would I from here, it needs to power the cooler 5.6amp, 8 low wattage lights, 2 sockets?

[Crossy]

I don't understand "#1 meter is 3/9" for starters.

 

We really do need photos.

 

I'm assuming we have two installations here, one for the shop on a 5/15 and one for the house on a separate meter - am I right here?

 

The shop should be easy. 5/15 => 30A main breaker => assorted sub breakers for the circuits. Wired like the diagram above.

 

EDIT Important, are you in Thailand?

 

 

[ilikethai]

42 minutes ago, Crossy said:

I don't understand "#1 meter is 3/9" for starters.

 

We really do need photos.

 

I'm assuming we have two installations here, one for the shop on a 5/15 and one for the house on a separate meter - am I right here?

 

The shop should be easy. 5/15 => 30A main breaker => assorted sub breakers for the circuits. Wired like the diagram above.

 

EDIT Important, are you in Thailand?

 

 

2 separate installations and locations, 1 for his home and 1 for his shop. 

For the shop but then wouldn't a 30A main breaker be too much from a 15A meter, I know we can stretch it but just to be on the technical safe side.  I was thinking 20A main breaker and then branch it out into 10A breakers.

 

I don't really know if photos would help because they're all over the places.  I attached pics of MCB and the CB's.  Over at his place they wire both the L and N wires to the CB and then out see pics.  In Southern BK where I'm staying they do meter, both L and N wire into main breaker then out from main breaker L and N and into sub breakers but only the L (hot) wires go through the sub breakers and the N (neutral) wires all go into the bus bar.

[sometimewoodworker]

1 hour ago, ilikethai said:

thanks for the fast reply.  Let's just say #1 meter is 3/9 how would I go from here, it needs to power 10,000 btu AC, water heater, small electric cooker, rice cooker, about 12 lights, 5 sockets?

 

As crossy has said that does not make any sense for Thailand.

 

However the load will not be more than a 5/15 meter will handle, assuming the water heater isn't too big. Though for a better answer. What is the power of the water heater and how long is it switched on? 

 

FWIW the 5 sockets don't use power ???? but if your going to be plugging more stuff in it will.

 

The 60A is doing nothing and will probably never trip. It should protect the wires from starting fires and it won't.

[sometimewoodworker]

Actually, I'm guessing here, there may be no consumer unit at all, just a lot of things wired directly from the meter all going through that 60 amp circuit breaker then to double pole switches that are being called circuit breakers like the 2 in the bottom picture.

 

They have no trip rating the 30A is just the power that they can carry and being called a safety breaker doesn't make them a circuit breaker, except in the sense that any switch breaks a circuit!

 

@ilikethai is there anything that looks remotely like this?

[ilikethai]

6 minutes ago, sometimewoodworker said:

As crossy has said that does not make any sense for Thailand.

 

However the load will not be more than a 5/15 meter will handle, assuming the water heater isn't too big. Though for a better answer. What is the power of the water heater and how long is it switched on? 

 

FWIW the 5 sockets don't use power ???? but if your going to be plugging more stuff in it will.

 

The 60A is doing nothing and will probably never trip. It should protect the wires from starting fires and it won't.

Ok What I will tell the pro is this.  5/15 meter out with 4mm copper wire with L and N wire both into 20A Main Breaker (I call this MCB), I will Earth it from here,  then out 2.5mm copper with only L (hot) wire into a sub breaker 10A (I call this CB) but the N (neutral) wire into busbar (neutral bar).  10A with 2.5mm wire solely for AC and Earth it.  10A solely with 2.5mm wire water heater just found out it's 3500W Panasonic heater.  10A or smaller for the rest of each point. 

 

the 3/9 meter I will do the same as like above and making the MCB as the distributor breaker branching out into smaller breakers. 

 

Basically I will make sure the MCB (main breaker) amp is matching or a little higher amp, say 15A for the 3/9 meter and 25A or 30A for the 5/15 meter? I will also match or try to over match my AC breaker, heater breaker, etc.  Right?

 

Clarify my friend's house and shop are in Laos.  I'm from BKK.

[sometimewoodworker]

1 minute ago, ilikethai said:

Ok What I will tell the pro is this.  5/15 meter out with 4mm copper wire with L and N wire both into 20A Main Breaker (I call this MCB), I will Earth it from here,  then out 2.5mm copper with only L (hot) wire into a sub breaker 10A (I call this CB) but the N (neutral) wire into busbar (neutral bar).  10A with 2.5mm wire solely for AC and Earth it.  10A solely with 2.5mm wire water heater just found out it's 3500W Panasonic heater.  10A or smaller for the rest of each point. 

 

the 3/9 meter I will do the same as like above and making the MCB as the distributor breaker branching out into smaller breakers. 

 

Basically I will make sure the MCB (main breaker) amp is matching or a little higher amp, say 15A for the 3/9 meter and 25A or 30A for the 5/15 meter? I will also match or try to over match my AC breaker, heater breaker, etc.  Right?

 

Clarify my friend's house and shop are in Laos.  I'm from BKK.

I think you have no circuit breakers at all, apart from the 60A one.

 

You just have switches like this one.

 

is that that what you have?

[ilikethai]

10 minutes ago, sometimewoodworker said:

Actually, I'm guessing here, there may be no consumer unit at all, just a lot of things wired directly from the meter all going through that 60 amp circuit breaker then to double pole switches that are being called circuit breakers like the 2 in the bottom picture.

 

@ilikethai is there anything that looks remotely like this?

yep!  but these "switches" are blocks like pics I provided.  It's like this:  Meter outside at the pole, to "Main Breaker" 60Amp (pic provided) in a living room  then to a smaller "breaker" or you call it "switch" 30Amp in a different room, etc.

[ilikethai]

2 minutes ago, sometimewoodworker said:

I think you have no circuit breakers at all, apart from the 60A one.

 

You just have switches like this one.

 

is that that what you have?

yes sir/mame!  over in this place they call them "breaker" or "circuit breaker".  So what does a "switch" 15Amp pic you provided and a "breaker" 60Amp pic I provided do?  Now I'm confused.  Time for me to go have a beer

[sometimewoodworker]

51 minutes ago, ilikethai said:

yes sir/mame!  over in this place they call them "breaker" or "circuit breaker".  So what does a "switch" 15Amp pic you provided and a "breaker" 60Amp pic I provided do?  Now I'm confused.  Time for me to go have a beer

 @Crossy will know exactly what they are I could be completely wrong and they are just surface mount units like these circuit breakers.

that go into a consumer unit.

 

I don't particularly want to open the one I have to check as I'm going to install it soon and I might just let the magic smoke out. ???? 

 

Anyway unless someone knows the Lao meter names you probably need a picture of the 3/9 meter as the current rating will be on it together with an estimate of the wire size (it may be printed on the wires) coming from it into your 60A circuit breake.

 

I think I've reached my level of safe knowledge now.

 

EDIT I've just proved that with the Chang breakers I may have exceeded it, see under 

 

I lied, I've just opened one (no magic smoke release) they do function in a similar way to the ones in a regular CU 

 

I don't know how much current has to pass through them for the heated metal strip to trigger, certainly more than the rating. So these need to match the size of the cables feeding them. The guidelines are here

 

The thing you seem to be missing (unless that 60A unit is one from the French system) is an RCCB 

 

[ilikethai]

19 minutes ago, sometimewoodworker said:

 @Crossy will know exactly what they are I could be completely wrong and they are just surface mount units like these circuit breakers.

that go into a consumer unit.

 

I don't particularly want to open the one I have to check as I'm going to install it soon and I might just let the magic smoke out. ???? 

 

Anyway unless someone knows the Lao meter names you probably need a picture of the 3/9 meter as the current rating will be on it together with an estimate of the wire size (it may be printed on the wires) coming from it into your 60A circuit breake.

 

I think I've reached my level of safe knowledge now.

 

EDIT I've just proved that with the Chang breakers I may have exceeded it, see under 

 

I lied, I've just opened one (no magic smoke release) they do function in a similar way to the ones in a regular CU 

 

I don't know how much current has to pass through them for the heated metal strip to trigger, certainly more than the rating. So these need to match the size of the cables feeding them. The guidelines are here

 

The thing you seem to be missing (unless that 60A unit is one from the French system) is an RCCB 

 

thank you so much.  it's pretty scattered when it comes to electricity here compare to back home BKK.  You're right I need some sort of Safty T Cut between the main breaker and the sub breakers. 

 

Again, please clarify, my old head is thick, so it's safe to go over Amp with the main breaker even though the meter 3/9 is outputting 1980watts right ( was told 9x220v=w)?

The sub breakers should be no more than 20 amp each device(s) point/room or dedicated device?

 

The 5.6amp beverage cooler needs 10A sub breaker, right?  Any breaker higher say 20A it will not trip unless the current pass the 20A mark?  So 10A breaker is good because it will only allow 10 amp to come into the cooler?

 

Since I will recommend my friend to have a distribution box please correct this--->

only the L (hot or live) wire needs to pass the sub breaker and the N (neutral) wire needs to go to bus bar, correct?

[sometimewoodworker]

2 minutes ago, ilikethai said:

thank you so much.  it's pretty scattered when it comes to electricity here compare to back home BKK.  You're right I need some sort of Safty T Cut between the main breaker and the sub breakers. 

 

Again, please clarify, my old head is thick, so it's safe to go over Amp with the main breaker even though the meter 3/9 is outputting 1980watts right ( was told 9x220v=w)?

The sub breakers should be no more than 20 amp each device(s) point/room or dedicated device?

 

The 5.6amp beverage cooler needs 10A sub breaker, right?  Any breaker higher say 20A it will not trip unless the current pass the 20A mark?  So 10A breaker is good because it will only allow 10 amp to come into the cooler?

 

Since I will recommend my friend to have a distribution box please correct this--->

only the L (hot or live) wire needs to pass the sub breaker and the N (neutral) wire needs to go to bus bar, correct?

You are asking questions that are better answered by someone who is more familiar with that kind of setup. 

 

However that 60A unit unless it's an RCCB (safe-T-cut) needs to go and be replaced by something smaller as it will never trip and almost certainly is too big for the cables.

 

The setup that is in place could be usable. The circuit breakers are there to protect the wires not the things running, a 10A breaker will probably allow 15A for hours and bigger currents for a shorter period.

 

With big wires you can always use smaller SMMCBs (surface mount miniature circuit breakers) but it's always the wires that are protected. With the SMMCBs you need both line and neutral (the neon needs that. In a CU it's only the line that goes through.

 

What problems are there? Or is it just to be safer?

 

If just to be safer then, subject to correction, an RCCB or two ( one for each meter) and probably resizing the SMMCBs to match the size of wire that they are on could be the answer, certainly  cheaper that fitting a modern CU. the benefit would be that the local Sparks will understand and be able to maintain it. 

 

You have talked about a voltage stabiliser but we haven't seen it yet, still waiting on the pictures of the meter and the cable sizes.

 

TTFN

 

[Crossy]

OK Things are much clearer now. Those "safety breakers" are indeed MCBs and will trip at something like 120% of rated current. Do feed both L and N through them as they don't all have the over-current protection on both poles.

 

Your 3500W heater will pull about 16A so should really be on a 20A breaker.

A 12000 BTU A/C will be using around 6A.

 

You can make things a lot safer, particularly around the water heater by replacing the existing 2-pole breakers with RCBOs. You can get ones that are the same form-factor for about 350Baht. Just ensure that the line (supply) and load ends are the correct way round.

 

Don't forget to ground the water heater, bash in a rod nearby if there's no rod currently in use.

 

If you do replace the existing system with a pukka distribution board (consumer unit) it will come with instructions, but yes the incoming supply goes to the 2-pole main breaker then the neutral goes to the neutral bar where all the circuit neutral also go. 

IMPORTANT If you buy the CU in Thailand it will show the incoming neutral wired to the ground bar first before going to the main breaker. This is the Thai way of wiring for MEN. I would suggest NOT wiring this way in Laos unless the local sparks says yes. I don't know if MEN is implemented by the supply authority.

 

EDIT @sometimewoodworker the 60A unit is not an RCD / RCCB but could be replaced by one of the little surface mount RCBOs, that would make things a lot safer at minimal cost.

[ilikethai]

7 hours ago, sometimewoodworker said:

You are asking questions that are better answered by someone who is more familiar with that kind of setup. 

 

However that 60A unit unless it's an RCCB (safe-T-cut) needs to go and be replaced by something smaller as it will never trip and almost certainly is too big for the cables.

 

The setup that is in place could be usable. The circuit breakers are there to protect the wires not the things running, a 10A breaker will probably allow 15A for hours and bigger currents for a shorter period.

 

With big wires you can always use smaller SMMCBs (surface mount miniature circuit breakers) but it's always the wires that are protected. With the SMMCBs you need both line and neutral (the neon needs that. In a CU it's only the line that goes through.

 

What problems are there? Or is it just to be safer?

 

If just to be safer then, subject to correction, an RCCB or two ( one for each meter) and probably resizing the SMMCBs to match the size of wire that they are on could be the answer, certainly  cheaper that fitting a modern CU. the benefit would be that the local Sparks will understand and be able to maintain it. 

 

You have talked about a voltage stabiliser but we haven't seen it yet, still waiting on the pictures of the meter and the cable sizes.

 

TTFN

 

here is the stabilizer.  When everything is off the right display it's always at around close to 10.

[ilikethai]

ok, here are the pics of his home meter and AC.  Please tell as much as possible what those important #'s mean.  20amp or 30amp main breaker for the 3/9 meter will be good size, right?  The RCCB (safe T cut or whatever) can be 30amp because I was told by the Spark any lower then 30amp they do not have them here unless I go with a different brand then maybe a 20amp RCCB. 

 

Conclusion and clarification; 

1. The main breaker can be a little over like 150% of the meter amp. 

2. The RCCB breaker can be a little over the main breaker.

 

I will definitely tell Spark to change the wires to proper size.  There are 1.5mm sq copper and a 2.5mm sq copper coming out from the shop meter.  It should be like only one double wire like a 16mm sq or bigger copper wire.

 

Also his shop roof is aluminum, so I will definitely tell Spark to run the main wire (from meter) using yellow pvc pipe.

[Crossy]

Is there any way to get the house meter upgraded to a 5/15? At least that wouldn't be oveloaded by the water heater alone.

 

Whilst electricity meters are very tough (a 100% overload won't blow it up) they can become inaccurate when overloaded and you can bet they don't read low.

 

[ilikethai]

4 minutes ago, Crossy said:

Is there any way to get the house meter upgraded to a 5/15? At least that wouldn't be oveloaded by the water heater alone.

 

Whilst electricity meters are very tough (a 100% overload won't blow it up) they can become inaccurate when overloaded and you can bet they don't read low.

 

Just talked to the Spark, he said the 3/9 meter should give out about 4,000 watts that's like 2x or 200%. 

"inaccurate" you mean at the expense of $$$?  So when they're stressed out they will read "higher" and we'll be paying more for electricity? 

[Crossy]

2 minutes ago, ilikethai said:

So when they're stressed out they will read "higher" and we'll be paying more for electricity? 

 

Pretty much, yes.

[sometimewoodworker]

@Crossy while I understand that what is in place is not OK practice in many places as most want everything to be in a Consumer unit. If the correct value surface mount RCBOs and surface mount MCBs are in place, wires are correctly sized etc is it intrinsically any less safe? Apart from the lack of earthing currently in place, that is.

 

It seems as if it's the same as a regular CU that got exploded and scattered around the house ???? 

 

It will certainly avoid any possible problems with shared neutrals though it could need a few more RCBOs and MCBs. Also careful segregation of wire before and after MCBs but nothing that's rocket science.

 

5 hours ago, Crossy said:

Those "safety breakers" are indeed MCBs and will trip at something like 120% of rated current. Do feed both L and N through them as they don't all have the over-current protection on both poles.

From my evisceration of my unit they also need the neutral for the neon lamp to tell you the current is actually on.

[Crossy]

If all those exposed breakers had the plastic terminal covers fitted (they get "lost" as soon as the box is opened) or they were in the little plastic housings usually found on the shelf next to them in the store then it would be no less safe than using a consumer unit (actually more safe as you have 2-pole breakers).

 

[sometimewoodworker]

4 hours ago, ilikethai said:

I will definitely tell Spark to change the wires to proper size.  There are 1.5mm sq copper and a 2.5mm sq copper coming out from the shop meter.  It should be like only one double wire like a 16mm sq or bigger copper wire.

Did you add an extra number? 6mm copper from each meter will be more than enough.

 

5 hours ago, ilikethai said:

here is the stabilizer.  When everything is off the right display it's always at around close to 10.

So you are saying that it's showing a 10A draw with everything turned off? If so then you probably have pirates stealing power.

 

4 hours ago, ilikethai said:

20amp or 30amp main breaker for the 3/9 meter will be good size, right?

30A is a little high for an MCB. I wouldn't go over 25A

 

30 should be OK for a safe-T-cut, as it's the line neutral imbalance that's going to trip it, and the MCB that trips on sustained over current.

 

 

[sometimewoodworker]

13 minutes ago, Crossy said:

If all those exposed breakers had the plastic terminal covers fitted (they get "lost" as soon as the box is opened) or they were in the little plastic housings usually found on the shelf next to them in the store then it would be no less safe than using a consumer unit (actually more safe as you have 2-pole breakers).

 

Humm, when I bought the one I opened in the picture above there were no terminal covers in the box. Next time I'm in those places I will check to see if I can find anything.

 

Thanks, 

BTW do you have a picture of a surface mount RCB? I'm being lazy but I should probably be using one of those on my home made wire wheel and buffing station, so if you've got a picture I won't have to argue that they do actually have one. I can find DIN and Cu fitting ones, but so far not surface mount.

[Crossy]

17 minutes ago, sometimewoodworker said:

BTW do you have a picture of a surface mount RCB?

 

Here you go, it even has the plastic terminal covers fitted ????

 

360 Baht or thereabouts plus 20-30 for the nice little box.

 

EDIT Important, you MUST get the Line and Load terminals the right way round, even if it means mounting the unit upside down.  If you swap line and load it works just fine, until you press the "Test" button at which point the magic-smoke comes out and it stops being an RCBO.

 

Cover looks something like this.

[farmerjo]

I put a cable meter after avr on both my 3500kw heaters and they draw 20 amps each with pump running when on full dial.

I have a 24,12 and 9 btu a/c's dual inverter and they all draw just under 4 amps each. 

[ilikethai]

sorry late reply.  first of all thank you to all you your knowledgeable answers.  I'd been busing running around town with my friend buying stuff to get started.  We'd decided to change and put in main breaker and RCCO and change all wires.  What's weird here is that I just saw a store that sells 5/15 meters a Mitsubishi for about 1200 baht and a Chinese fake for 300 baht.  We were told just buy the meter and install it and the electricity worker will do the rest!  Yeah weird.  Anyway thank everybody so much and for everything and will keep you updated

[carlyai]

here is the stabilizer.  When everything is off the right display it's always at around close to 10.

I'm not saying that this is the problem, but I have 3 of the same types of stabalisers, and one of my stabaliser meters reads high (off the scale) but checking the output voltage everything is OK. Maybe they have sus. meter circuits?

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