Help: made a big boo boo need solution.

[PermaNewb]

Hello I've been reading the sparky forum and have learned enough to completely confuse myself. I'm an idiot when it come to electricity and I've made a major boo boo and am in need of some help to figure out a solution...

here goes.

a bit of context...

My wifes father built us a house in the middle of nowhere, surrounded by rice paddies and made the financially fatal mistake of getting a price for the house including all materials and leaving everything up to the "builder". so you long timers will undoubtedly know the result...the cheapest of everything...we are in the process of multiple upgrades...

we've come to the electrical system...Father built three houses, one for us, one for the brother(no really I had DNA testing done) and one for himself...all three houses are on one 15/45 meter so right away even I could figure out that that is not enough juice...

so we're planning to split the feed and purchase another meter just for our house. The problem is I'm not sure if another 15/45 meter will suffice or if we should go with a 30/100 and here's why...

we made a real stupid rush decision and purchased a 30000 btu air con for the main room which is 48sqm without thought for the super cheap electrical installation...we've had it hooked up and it won't run...trips the 30amp breaker as soon as the compressor kicks in. I did a voltage test this morning and we are getting 220 volts, but with everything on (minus the monster aircon) voltage drops to about 180...after turning everything else off and firing up the monster we get a voltage drop to 145volts when the compressor kicks in and the breaker trips... the aircon is rated at 3300 watts with a cooling capacity of 8800 watts and a 14.22 amp draw. here's a pic of the unit and the label...

ok a bit about the existing wiring...here's our consumer box

the living room lights consist of 12 pot lights with Phillips Superlux 40 watt bulbs and 4 round florescent as well as a round fluorescent porch light, a round fluorescent garage light and 2 25watt bulbs on the front steps...now get this...they are all on one circuit, the second right from the main in the pic which is a 16amp...now I think that is way too much for one circuit, tell me if I'm wrong...but guess what? the monkeys who installed the monster aircon wired it into that same circuit!! they just chose the closest wire...I wasn't home when they did it...

all the livingroom wall sockets are 2 prong and the garage is an ungrounded 3 prong and all 5 of them are on one circuit with a 20amp (third right from main in pic) that all makes up one side of the house.

on the other side of the house is the bedroom, bathroom and kitchen...all three rooms lights are on one circuit and all three wall socket(2 prong) are on one circuit. The aircon in the bedroom (12000btu,3600w, 4.7a) is on it's own circuit with a 32a breaker. the water heater (3200w) is on it's own circuit with a 32a breaker.

So, is it as much of a mess as I think it is?

what should be re-wired? Obviously the monster aircon should be...recommendations? wire, breaker, grounding?

I hear the fridge, which is plugged into one of the living room wall sockets, should be on it's own circuit, yes?

Should we split the bedroom, bathroom, kitchen wall sockets?

is a 15/45 meter for our house alone good enough, or should we move up to 30/100?

if we move up to 30/100 do we need bigger wire, bigger breaker? recommendations?

what about a voltage regulator? would a VR in conjunction with the 15/45 meter be enough? If it's suggested that we get a VR what size would be suitable considering the monster aircon?

I know it's a lot but I would appreciate any help with this as we have no one reliable out here to ask for advice...

[Crossy]

A proper 15/45 connection would probably suffice (just) for your home only if you can't get a 30/100 from your local supply.

The problem is that you already have significant volt drop, and simply installing a bigger meter won't help. This could be the local infrastructure or (with luck, easier to fix) the wiring from the pole to your homes.

How far from the supply poles is your home? How thick is the cable supplying same (it should be marked)?

I suggest a visit (with a Thai speaker) to your local PEA office to see what can be done.

[bankruatsteve]

As Crossy said, your main issue is supply voltage. But, just to add a few things:

I would move the 'monster' A/C wire from the 16a breaker shared with lights to the 32a breaker with the other A/C unit. The lights are OK on the 16a.

If your house is at a point that re-wiring is practical, you would certainly want to add ground and 2-3 more circuits.

In any case, you should change out the main breaker to RCBO or replace the CU with "Safe-T-Cut".

[PermaNewb]

A proper 15/45 connection would probably suffice (just) for your home only if you can't get a 30/100 from your local supply.

The problem is that you already have significant volt drop, and simply installing a bigger meter won't help. This could be the local infrastructure or (with luck, easier to fix) the wiring from the pole to your homes.

How far from the supply poles is your home? How thick is the cable supplying same (it should be marked)?

I suggest a visit (with a Thai speaker) to your local PEA office to see what can be done.

Thanks...that's good news..

the meter is on a pole less than 2 meters from our house and the wire is 25 sqmm aluminum.

we've got the PEA guys coming on Friday with both meters and he says he's going to test both...he also believes that the 30/100 is a waste of money.

[PermaNewb]

As Crossy said, your main issue is supply voltage. But, just to add a few things:

I would move the 'monster' A/C wire from the 16a breaker shared with lights to the 32a breaker with the other A/C unit. The lights are OK on the 16a.

If your house is at a point that re-wiring is practical, you would certainly want to add ground and 2-3 more circuits.

In any case, you should change out the main breaker to RCBO or replace the CU with "Safe-T-Cut".

see told you I was an idiot...that never occurred to me and makes perfect sense seeing as we'll never have both ac running at the same time...

thanks.

[bankruatsteve]

If you get the supply voltage solved, you can happily run both A/C's at the same time from the one breaker if you want.

[PermaNewb]

Apparently the transformer is less than 500 meters from our house and we are the last property on it...we are the end of the line...

does that have any bearing on my voltage drop issues?

[wayned]

IMHO, the 30/100 is a waste of money if the supply won't support your load!

[PermaNewb]

Well the PEA guy sort of alluded to the fact that the the bigger meter won't help...he said "I can put one in but I won't guarantee that you'll get more power"...so it seems that he knows the supply isn't up to snuff.

if that is the case is the fix a Voltage stabilizer? I read on another thread that some guys with supply issues solved their problem with one and were quite happy with the result.

[IMHO]

If your aircon draws 14.22 Amps @ 220v, it draws 21.6 Amps @ 145V. Add in startup current of 3x, and that becomes 64.8 amps, which trips the 200% rated 30A breaker.

The problem is voltage drop.

The solution? hopefully it's wiring and something the PEA can fix - if not, you might become the next customer for a voltage stabilizer....

[PermaNewb]

If your aircon draws 14.22 Amps @ 220v, it draws 21.6 Amps @ 145V. Add in startup current of 3x, and that becomes 64.8 amps, which trips the 200% rated 30A breaker.

The problem is voltage drop.

The solution? hopefully it's wiring and something the PEA can fix - if not, you might become the next customer for a voltage stabilizer....

ok, this morning I tested voltage and was getting 220v with everything turned off...when I turned on the monster, the inside unit was on but it takes 3 minutes to warm up the compressor...for that 3 minutes I'm still reading 220v even with the fan on the inside unit running...then as the compressor tries to fire up I get a drop to 145v and the breaker trips.

is that how you understood it?

[Crossy]

Task a ) bigger breaker, 50A (the biggest you should have on a 15/45, ok maybe 63A).

Task b ) see if it actually manages to start on 150V, once running the current will fall off to sensible levels.

If it does start and run a stabiliser may save you, but by far the best solution is to get PEA to sort the supply.

[bankruatsteve]

His main breaker is 63a. PermaNewbe, what is the specification of your internal wiring? IE: for the lighting circuits, the receptacle circuits, the A/C, etc? By that, I mean what size? 2.5mm2? or what?

Which breaker trips? Are you still on the 16a breaker for your 'monster'?

[thomasteve]

Looking at your photo it shows a thick black neutral wire coming out from the main breaker which goes to the neutral busbar - that connection needs redoing - as most of the stranded wires have been cut off to fit into one screw hole on the busbar.

If necessary as a 'fix' spread and divide the strands out to share 2 of the rather small terminal holes of the busbar.

This will prevent any risk of overheating as the wire will then be able to carry it's full rated current.

[PermaNewb]

Looking at your photo it shows a thick black neutral wire coming out from the main breaker which goes to the neutral busbar - that connection needs redoing - as most of the stranded wires have been cut off to fit into one screw hole on the busbar.

If necessary as a 'fix' spread and divide the strands out to share 2 of the rather small terminal holes of the busbar.

This will prevent any risk of overheating as the wire will then be able to carry it's full rated current.

yeah, I was wondering when someone was going to notice that...what was the sparky thinking? I saw that and even to me it just makes sense to fork the wire and use two screw holes not remove 2/3 of the wire. I'm going to get that taken care of...thanks

[PermaNewb]

His main breaker is 63a. PermaNewbe, what is the specification of your internal wiring? IE: for the lighting circuits, the receptacle circuits, the A/C, etc? By that, I mean what size? 2.5mm2? or what?

Which breaker trips? Are you still on the 16a breaker for your 'monster'?

as far as I can tell it's all 2x2.5sqmm...

the breaker that trips is the one they usually install with a A/c unit usually on the wall by a light switch, the monster has a Chang 30a...if I only turn on the monster the chang 30a on the wall trips...if I have the living room lights on when I turn on the monster then the 16a light circuit trips in the consumer box.

[thomasteve]

You should definitely have 3 pin earthed socket outlets fitted throughout, together with a proper earthing rod and fit a RCD (eg. Safe-t-cut) as a minimum.

It is not necessary for the fridge to have it's own circuit - that's more of a 'nice to have'.

As for rearranging the circuits, that may be quite tricky as they tend to combine lighting and socket outlet wiring for each room onto the same wiring (rather than having all lighting on one separate circuit ) and then have one or two rooms joined up per circuit breaker.

Air-cons and other heavy loads, such as water heaters, should have individual circuit breakers if at all possible.

You may have to compromise though as some of the wiring may now be inaccessible to rearrange and there may not be enough space in the consumer unit for any extra circuit breakers. Priority should be to get the earthing sorted out and the RCD fitted.

EDIT : reading your post again, it seems pretty much ok as it is - you have 2 circuits for lighting (good idea so all lights don't trip together) and 2 for the socket outlets. You just need an additional new breaker for the 'monster' air-con and earth wires for the socket outlets, air-cons and shower heater.

[IMHO]

If your aircon draws 14.22 Amps @ 220v, it draws 21.6 Amps @ 145V. Add in startup current of 3x, and that becomes 64.8 amps, which trips the 200% rated 30A breaker.

The problem is voltage drop.

The solution? hopefully it's wiring and something the PEA can fix - if not, you might become the next customer for a voltage stabilizer....

ok, this morning I tested voltage and was getting 220v with everything turned off...when I turned on the monster, the inside unit was on but it takes 3 minutes to warm up the compressor...for that 3 minutes I'm still reading 220v even with the fan on the inside unit running...then as the compressor tries to fire up I get a drop to 145v and the breaker trips.

is that how you understood it?

Yep.

[PermaNewb]

You should definitely have 3 pin earthed socket outlets fitted throughout, together with a proper earthing rod and fit a RCD (eg. Safe-t-cut) as a minimum.

It is not necessary for the fridge to have it's own circuit - that's more of a 'nice to have'.

As for rearranging the circuits, that may be quite tricky as they tend to combine lighting and socket outlet wiring for each room onto the same wiring (rather than having all lighting on one separate circuit ) and then have one or two rooms joined up per circuit breaker.

Air-cons and other heavy loads, such as water heaters, should have individual circuit breakers if at all possible.

You may have to compromise though as some of the wiring may now be inaccessible to rearrange and there may not be enough space in the consumer unit for any extra circuit breakers. Priority should be to get the earthing sorted out and the RCD fitted.

EDIT : reading your post again, it seems pretty much ok as it is - you have 2 circuits for lighting (good idea so all lights don't trip together) and 2 for the socket outlets. You just need an additional new breaker for the 'monster' air-con and earth wires for the socket outlets, air-cons and shower heater.

Ok thanks. Fortunately with a bargain install 90% of the wiring is exposed so access is not a problem. So I'll have the PEA guys re-wire the monster and run ground wires to the necessary locations.

[PermaNewb]

If your aircon draws 14.22 Amps @ 220v, it draws 21.6 Amps @ 145V. Add in startup current of 3x, and that becomes 64.8 amps, which trips the 200% rated 30A breaker.

The problem is voltage drop.

The solution? hopefully it's wiring and something the PEA can fix - if not, you might become the next customer for a voltage stabilizer....

Hello IMHO, or anyone who can answer...

The PEA was here today and installed the new 15/45 meter. After installation we tried the monster and no joy, although the voltage drop from the compressor start up was 155v instead of the previous 145v.

Then they left and 3 minutes later our power cut off...then 5 minutes after that it came back on and shortly thereafter they returned to tell us that they had adjusted the transformer and we are now getting 235v...tested that and it's true...tried the monster again and still no joy, but now we get a voltage drop to 165v when the compressor kicks in.

so it looks like we need a voltage stabilizer to successfully run this aircon, my question is, can we get away with wiring a voltage stabilizer just into the aircon circuit, as I imagine that would be a smaller unit and therefore less costly and if so what size would we need?

[Crossy]

They've upped the tapping at the Tx to try to mitigate the volt drop.

Is it still opening the breaker? Yes? Bigger breaker and it may now start.

You can just wire a stabilizer for the monster, look for something around twice the rated capacity of the compressor, say about 6kVA.

BUT it may still not solve the issue as the stab will draw more current from the supply to try to maintain the output voltage, it could just cause the supply to collapse.

[PermaNewb]

They've upped the tapping at the Tx to try to mitigate the volt drop.

Is it still opening the breaker? Yes? Bigger breaker and it may now start.

You can just wire a stabilizer for the monster, look for something around twice the rated capacity of the compressor, say about 6kVA.

BUT it may still not solve the issue as the stab will draw more current from the supply to try to maintain the output voltage, it could just cause the supply to collapse.

yes still opening the breaker...PEA guy said same = bigger breaker...what size?

supply collapse?!...that doesn't sound too good.

could you splain that crossy? Like i'm ten years old...

[Crossy]

Breakers are not expensive, if it's opening a 30A get a 40A and 50A, keep the smallest that doesn't open.

Assuming it's not the incomer that's opening you could simply bypass the breaker that is, and try again, your supply will be protected by your 63A incomer, obviously not a situation to leave but it will give you an idea whether your supply can support starting the beast. If it starts then you have a fighting chance with an AVR (Automatic Voltage Regulator or stabilizer).

As to supply collapse, drawing more current will cause the voltage to fall further, which will cause the AVR to pull more current, which will cause the supply to fall further, a viscous circle. Eventually the transformer will saturate, when this happens the incoming HV breaker (or fuse) will open to protect the transformer. Power cut until the man comes to reset.

[PermaNewb]

got it. Thanks Crossy.

[Crossy]

If it's not an inverter drive compressor you may be able to retrofit a soft-starter to lessen the switch-on surge, not seen them in Thailand but worth a Google to see what's available.

If all else fails, bite the bullet, sell the monster and buy two units half the size.

EDIT These guys may be able to help, make sure they understand you need a single-phase unit http://www.tgcontrol.com/?p=426

[PermaNewb]

Breakers are not expensive, if it's opening a 30A get a 40A and 50A, keep the smallest that doesn't open.

Assuming it's not the incomer that's opening you could simply bypass the breaker that is, and try again, your supply will be protected by your 63A incomer, obviously not a situation to leave but it will give you an idea whether your supply can support starting the beast. If it starts then you have a fighting chance with an AVR (Automatic Voltage Regulator or stabilizer).

As to supply collapse, drawing more current will cause the voltage to fall further, which will cause the AVR to pull more current, which will cause the supply to fall further, a viscous circle. Eventually the transformer will saturate, when this happens the incoming HV breaker (or fuse) will open to protect the transformer. Power cut until the man comes to reset.

ok now we're getting somewhere...I just did what you suggested crossy I bypassed the 30amp breaker, but the AC is was still on the 16amp light circuit so of course it opened... Then I took the wire out of the 32amp circuit running the bedroom AC and took the wire from the 16amp light circuit and put it on the bedroom AC 32 amp circuit...

the monster is alive!!...it's running right now...before the compressor kicked in I was reading 240v and it dropped to 170v and the compressor fired up...I'm going to run it for a cycle to see if it fires up a second time after a shut down...

so is it going to be ok if I have the AC guys rewire it to it's own 32amp circuit?...I think so, am I out of the woods here or is the 170v drop still a problem?

we called the AC guys who did the install and they're coming out tomorrow...

ps. I'm reading 220v while the monster is running on high fan at 26 degrees...

[Crossy]

Well we know it actually works

Yes, put it on its own circuit, if a 32A is holding that's fine (I wonder if that 30A is defective).

How are you measuring the supply voltage (digital meters are notoriously inaccurate on transients)?

How long does the voltage stay at 170V?

My only worry now is that you could be reducing the life of your compressor motor by expecting it to start every time on 170V, but as I said, your meter could be leading you astray here.

I would still price a suitable AVR and use it if budget allows, the compressor will be fine in the short term connected as is.

[PermaNewb]

ok great, now I have to admit to a noob goof...

yeah I'm using a cheapish multimeter in a wall socket...it's all I've got right now.

it drops to 170v and stays there for about 3 to 5 seconds and then the motor fires and it jumps back up to 220-ish.

now that we know that the supply can start and run it...but as you say I could be slow killing the monster with them voltage drops...would a 6K voltage stabilizer help?

[Crossy]

3-5 seconds is quite a long time, I would certainly be looking at that AVR, if you can get one on "return if too small and swap for a bigger one" that would be a smart move.

Maybe get a really big one (50A) and do the whole house

[PermaNewb]

yeah I think that's the way to go...but I'm a bit confussed about the numbers...on the "voltage drop solved" thread the op talks about the SH10000 and states he bought a 45amp one and was happy with it...so what would the minimum be for my place knowing what you know so far?