Electricity leakage

[JohnnyJazz]

We have an island in the middle of the kitchen with two separate cables coming from the ground. One of the cable goes to a power outlet, no problem. The second goes to an induction cooktop that stopped working a couple of weeks ago. The Electrolux guy came and said no problem with my cooktop, the problem is with the electricity supply, no electricity in the cable. We checked the main switch and it's ok. Today the kitchen company came to solve other problems, we asked them to have a look at this cooktop problem and this time they found electricity but only 120 V instead of the regular 220

The electrician who did the installation for the house is "very busy", we are waiting for him for the past two weeks and nobody has any idea how was the cabling done between these two cable that come from the ground and the main switch board. What puzzles me the most is how comes one day we have electricity, the next day we don't and a bit later only 120 instead of 240V.

Any idea what could be wrong with our electricity installation ?

[RichCor]

Are you sure you're in Thailand?

Well, that's not fair ...anything weird can happen in Thailand.

Do the wires from the CU (Main Switch Board) go directly to the kitchen island (same colors at both ends) or is there some connection in between?

Is it an isolated/dedicated breaker in the CU, and what voltage do you get at the breaker?

Are you on a Single Phase AC, or 3-Phase AC, and are any other appliances (fans, lights,) having issues?

[JohnnyJazz]

Are you sure you're in Thailand?

Well, that's not fair ...anything weird can happen in Thailand.

Do the wires from the CU (Main Switch Board) go directly to the kitchen island (same colors at both ends) or is there some connection in between?

Is it an isolated/dedicated breaker in the CU, and what voltage do you get at the breaker?

Are you on a Single Phase AC, or 3-Phase AC, and are any other appliances (fans, lights,) having issues?

Thanks for the quick answer

Single phase and so far the problem is only with the induction cooktop.

According to the indication left (in Thai) by the electrician there is a dedicated breaker for this part of the kitchen but not sure how many and which appliances are connected to this breaker. Not sure either if the wires go directly from the breaker to the the kitchen island. If I remember correctly they go first to a box in the wall and from there under the tiles to the island. The box is now behind a built-in cabinet :-(

I will check tomorrow for the voltage at the breaker and let you know.

[RichCor]

A dedicated breaker would mean only that appliance is connected (not shared with other appliances).

Induction cooktops pull LOTS of current to get the magnetic coils oscillating.

Can't imagine what would cause a 220-240v circuit to provide only 120v unless it was connected midway to an isolating transformer that was failing.

[Crossy]

Reading 120V is likely a phantom voltage coupled from a live circuit unless you have a really poor joint (which you would likely have smelled by now).

Try turning all the breakers off then back on, it's possible something has tripped but the lever hasn't dropped.

[zib]

Umm if it's singlephase isn't it two legs of 110v each. So the reason you are getting ~120V is because your appliance is actually being connected to live/line and the ground wire. instead of live+live.

So either one of the ground,live-wire is connected wrong or the more common here, ofortunately, that the ground wire melted together with one of the live wires.

[Suitcase]

Years ago had an A/C installed and several weeks later it quit working.

Checked for juice and there was electricity to the unit.

Did not know there was two legs of 120V each.

$60 for the technician and a $5 fuse.

Dummy me!

Electricity 101 can be a little expensive!

Most of us do not know much about electricity other than changing

a light bulb.

[Crossy]

NO NO NO ^^^

We are not in the US, single-phase here is 220V L-N with the neutral at approximately ground potential (0 Volts).

[bankruatsteve]

Guys, in Thailand single phase is 2-wire (L,N) 220v. USA electrics are completely different.

Outside of low voltage, the only way to get 120v here is, as Crossy said phantom. Another possibility could be a damaged neutral with fault to ground.

[wayne07836]

Sounds to me like you have a loose neutral or you have lost the neutral, still got 220v through the phase conductor but the potential difference will not give you 220v if the neutral is loose or has beecome disconnected. look at the neutral cable in the distribution board for the circuit.

Or even the main incoming neutral could be loose but not totally disconnected, when you apply a heavy load such as a cooker, the loose neutral will cause arcing and a risk of fire but will also give you the strange voltage that you are seeing.

Try this, switch on all of you lights, then turn on the cooker to see if your lights dimm, if so the it sounds like the main neutral is a bad connection.

[SOTIRIOS]

...not a good idea to explore blindly when there is a leak....be very careful...especially in a wet environment.....

...true that many electricians will join bits and pieces of wire to make a full length...then charge you the regular price.....

...but if you do not know where the 'leak' is...and what it could possibly come in contact with....please be careful....

[JohanB]

Are you sure you're in Thailand?

Well, that's not fair ...anything weird can happen in Thailand.

Do the wires from the CU (Main Switch Board) go directly to the kitchen island (same colors at both ends) or is there some connection in between?

Is it an isolated/dedicated breaker in the CU, and what voltage do you get at the breaker?

Are you on a Single Phase AC, or 3-Phase AC, and are any other appliances (fans, lights,) having issues?

Thanks for the quick answer

Single phase and so far the problem is only with the induction cooktop.

According to the indication left (in Thai) by the electrician there is a dedicated breaker for this part of the kitchen but not sure how many and which appliances are connected to this breaker. Not sure either if the wires go directly from the breaker to the the kitchen island. If I remember correctly they go first to a box in the wall and from there under the tiles to the island. The box is now behind a built-in cabinet :-(

I will check tomorrow for the voltage at the breaker and let you know.

I belive the problem is in the "box" in the wall behind the kitchen cabinet. If you have a live wire going out from your CU to the box, and no voltage in the vire from the box, the fault must be there.

Maybe there is a fuse in the "box" that have tripped by the high current to the stove. Maybe one of these cheapo connection

bars with a switch and fuse is situated in the "box"? Maybe a thai-style-twisted-connection is lose

Try to locate the box and cut a hole in the backside of the built-in-cabinet to get access to it. The answer will probably be there.

Otherwise someone has cut the wire by misstake in some other place between.

When you got the wires sort out and found the break, you must check if the conductors area in the cable feeding the stove is correct. I think you need a 2x 2.5mm2 area cables for that.

Rule of thumb for that is, at least in Sweden (230VAC): 1mm2 = 6Amp, 1.5mm" = 10Amp, 2.5mm2 = 16Amp

The 120VAC someone measured is probably just what the meter shows when the cable is not connected to a load and picks up stray field from the other voltage carrying cable beside.

Will show different voltages depending what meter is used. This voltage is high impedance and carries no current.

[Remi080]

I think... You better build a kitchen on a Island in stead a Island in a kitchen.

Well... If thats not gonna solve the problem..

[jacko45k]

I suspect a bad neutral/return wire or bad supply breaker.

Really not easy to figure out if you do not understand electrics very well, that may be you, but could also be true of any odd electrician you get to come check things out.

Using a digital voltmeter can sometimes confuse as you may be measuring a floating voltage or relative to one.

And connections are often poorly tightened here.

I would first determine which circuit breaker was feeding the island and measure the voltage on both sides of it relative to both neutral and earth. Should be about the same at 240vAC.

You could then do the same at the cooker end off load and on load.

You may have to get at the connection box behind the cabinet... never a good idea to block access to these.

If you are not confident with electrics I really don't recommend you mess with it yourself.

[Liquorice]

Start tracing by turning off the dedicated breaker and see how many appliances/fittings are affected.

If it's just the cooktop, then check the jointing box.

If it's more than one appliance then it could be a nightmare to trace.

It could be the appliance at fault.

Did they find the 120V with the cooktop connected or disconnected?

[JohnnyJazz]

Start tracing by turning off the dedicated breaker and see how many appliances/fittings are affected.

If it's just the cooktop, then check the jointing box.

If it's more than one appliance then it could be a nightmare to trace.

It could be the appliance at fault.

Did they find the 120V with the cooktop connected or disconnected?

The appliance is not at fault (so far). The first person to come was the Electrolux guy (manufacturer of the appliance). He checked, and we double checked, there is no electricity coming from the cable. The cooktop is now disconnected and when the kitchen manufacturer came, he triple checked and he found 120V (???) in the cables that are going to to the cooktop.

The kitchen is three month old and still under warranty. Basically there are three parties involved, the appliance manufacturer, the kitchen manufacturer and the electrician. The only one who has not come yet is the electrician. As usual nobody is responsible and they are all rejecting the responsability on the other guys. For the time being I don't want to be involved because 1/ the kitchen is still under warranty and 2/ if I do anything they will then all agree the farang is responsible for the problem. So for the time being I will check the breakers, see what's going on when I turn them on/off, wait for the electrician to show up and pray we won't have to disassemble our brand new kitchen to fix this problem.

[Crossy]

Stick a lamp (regular incandescent type) on the end of the cable that's now disconnected from the cooktop, your 120V should disappear. Assuming it does that was a phantom pickup voltage, nothing to worry about.

Now it's time to work out why there's no connection between the breaker and the cooktop connections.

[JohnnyJazz]

Now it's time to work out why there's no connection between the breaker and the cooktop connections.

Loose connection in the breaker. The electrician was adamant that someone has tampered with his work as he had "personally" checked every connection before leaving (smart move that I didn't try to fix anything). But at least he was able to identify the problem within 10 mn after arriving home.

In the process I was able to learn that every major appliance in the kitchen has its own breaker. Everybody looked at me as i was a total retard as it is written on the switchboard ... in Thai !!!

Now they are back to the blaming game but the kitchen is fixed and we won't have to open the wall so I really don't give a hoot

[Crossy]

On some breakers it's quite easy to get the wire behind the cage and torque up the screw.

If you don't do the 'wiggle' test (pull on the wire) you would never know, it would work for a while until the loose connection fizzed open.

Glad it's sorted.