Thought my inverter had failed .....

[BritManToo]

So the electricity from the inverter went off, inverter showing fault.

Fiddled around restarting, bit of sizzling, fault returned.

 

But with the kitchen MCB off, everything else works and no fault and no sizzling.

Kitchen supply all on one fuse connected to the inverter.

Kitchen sockets x2, kitchen light, car port light, under-stairs light, gate light, doorbell all on one wire disappearing into conduits sunk into the wall.

Would have to take the kitchen ceiling down to trace it all out.

 

Lucky I have grid tied sockets in the kitchen as well added myself directly to the fuse box on its own circuit when I first installed solar.

So a quick extension lead to the fridge and microwave to get them working.

 

Don't know what to do about the rest, can't be bothered taking the ceiling down.

Will need to think carefully how to run a new lighting circuit with it's own MCB.

Generally I've found the inverter much quicker to find fault and turn off than any of the MCBs.

[BritManToo]

Electricians in, pulling burnt wires out of the wall from fuse box to ceiling.

Not sure how this could have happened ........ any ideas?

[couchpotato]

if all your wiring is the same as the first picture, then it is dangerous, and you were lucky you only had a small area burn't.  Wiring these days should be enclosed in Electrical PVC (either rigid or flexible), with proper junction boxes.

Looking at the photo it could have been 2 wires shorted together or there seem to be lots of rodent/lizard droppings on the ceiling, which could also account for the fault.

So my advice would be to spend a bit of money and fix your wiring properly before a larger problem occurs.

[BritManToo]

14 minutes ago, couchpotato said:

if all your wiring is the same as the first picture, then it is dangerous, and you were lucky you only had a small area burn't.  Wiring these days should be enclosed in Electrical PVC (either rigid or flexible), with proper junction boxes.

Looking at the photo it could have been 2 wires shorted together or there seem to be lots of rodent/lizard droppings on the ceiling, which could also account for the fault.

So my advice would be to spend a bit of money and fix your wiring properly before a larger problem occurs.

This photo was of the wires pulled out of the trunking, sunk in the concrete house walls

........ obviously.

You thought the wires were just lying around randomly on the kitchen floor?

Unbelievable

 

So why would they burn in the trunking, no high loads on anything.

[fredwiggy]

Burnt wires usually mean an overload or wires too old to handle added circuitry and loads...........https://www.abelectricians.com.au/what-are-the-causes-of-melted-wires/.

[BritManToo]

9 minutes ago, fredwiggy said:

Burnt wires usually mean an overload or wires too old to handle added circuitry and loads...........https://www.abelectricians.com.au/what-are-the-causes-of-melted-wires/.

House is 12 years old.

All the heavy kitchen loads plugged into direct wire from fuse box to socket, not in walls.

[fredwiggy]

2 minutes ago, BritManToo said:

House is 12 years old.

Mine is 7 and the builder wasn't too swift, and I had shocks when I touched the microwave or toaster. Improper grounding causes shorts and burnt wires, as does old connections, mice, lizards and bugs. High humidity causes these problems in places like Thailand, Florida, east Texas, Louisiana and other like places

[fredwiggy]

This is from black plastic trunking but it still has the same problems..........https://www.cmwltd.co.uk/blog/cable-management-containment/troubleshooting-common-problems-with-black-plastic-maxi-trunking?srsltid=AfmBOoo4TrdaHYZrOp4ODeBPDtSAhitY8Qe6eWfPxBdp27QOjwCV9lNI.

[novacova]

On 7/16/2025 at 10:49 AM, BritManToo said:

Kitchen supply all on one fuse connected to the inverter.

Kitchen sockets x2, kitchen light, car port light, under-stairs light, gate light, doorbell all on one wire

Possibly the circuit is drawing more current than what the wires are rated for. Or corrosion on the wire, high resistance.

On 7/16/2025 at 10:49 AM, BritManToo said:

all on one wire disappearing into conduits sunk into the wall.

Would have to take the kitchen ceiling down to trace it all out.

Are you sure there isn’t an attic opening/door in another room in the house to access the kitchen wiring? Haven’t seen any newer houses without one.

[BritManToo]

17 minutes ago, fredwiggy said:

Mine is 7 and the builder wasn't too swift, and I had shocks when I touched the microwave or toaster. Improper grounding causes shorts and burnt wires, as does old connections, mice, lizards and bugs. High humidity causes these problems in places like Thailand, Florida, east Texas, Louisiana and other like places

When I first moved in the first thing I discover, Live and Neutral from the meter reversed.

So all fuses on the neutral line and ineffective, and all the Live wires live 24/7.

 

Talked to the electrician,

He says all 250 houses in the moobaan have electrical problems, some wired in the bathroom, some wired in the kitchen. The wire used was all cheap or substandard, and it's unlikely anything me or anyone else in the house did, caused the problem. It was a fault waiting to happen.

 

He also said my wiring for the inverter was poop, but didn't appear to be the problem.

[fredwiggy]

1 minute ago, BritManToo said:

When I first moved in the first thing I discover, Live and Neutral from the meter reversed.

So all fuses on the neutral line and ineffective, and all the Live wires live 24/7.

 

Talked to the electrician,

He says all 250 houses in the moobaan have electrical problems, some wired in the bathroom, some wired in the kitchen. The wire used was all cheap or substandard, and it's unlikely anything me or anyone else in the house caused the problem. It was a fault waiting to happen.

Many Thai builders look to save as much money as possible, safety not a great concern for some. When I mentioned this to friends here, they said the same things."I had to replace all the wiring", "The paint faded in a year (One of my problems), "I got shocks touching my computer, appliances etc", (my son in law, who's done AC servicing for years, said they didn't install a proper ground. I'm not staying here any longer than I need to, or else I would replace everything electrical here.

 

I was going to hire a Brit builder, who hires good locals, but it would have cost quite a bit more. That was a mistake, as he had great references and traveled countrywide. 

[Schoggibueb]

One phase and not three phase I guess

 

2.5sqmm does for the most -> 16A. If you would have an electric stove, or even an induction, that can go up to 10sqmm - depending on the load / what your device is pulling.

 

 

Further, if the connection points, or connections in junction boxes are corroded, screws not tightend properly etc it can have the same effect.

 

Maybe I missed it in the discussion... Do you have a RCB / RCBO for safety?

I am quite sure not, because that would / should have tripped much earlier.

 

 

 

 

 

 

[Schoggibueb]

What I have seen very often, that all fuses have 20A or higher. Of course it works... 

But that is exactly what can happen as you have on your pictures. 

I also had to insist and checked again, that they use the correct fuses according to the used wires.

You have to be strict about that, because they really don't care.

[BritManToo]

28 minutes ago, Schoggibueb said:

2.5sqmm does for the most -> 16A. If you would have an electric stove, or even an induction, that can go up to 10sqmm - depending on the load / what your device is pulling.

All heavy power kitchen loads plugged into dedicated sockets running direct from MCB in fuse box to socket under fuse box. Not in walls.

 

Only 'in wall' kitchen load fridge and 1.4Kw microwave.

Only 'in wall' heavy load upstairs is a 1kw iron in the bedroom.

Just Tvs, fans, ceiling lights powered from wires in the walls

Fuses all 10A, wiring all 2.4mm single.

 

ALTHOUGH the poop heads only used 1 neutral wire for the 3 upstairs bedrooms, sockets and lights, but don't see how max load would exceed 14A.

 

Also all 'in wall' circuits powered from inverter with output switching so sensitive, any mismatch in power live/neutral switching off so quickly, if it were your finger, you wouldn't feel it.

 

Air con and shower heater on separate circuits not burnt.

 

Entire house load when wires burned .......... 8pm ish 150W

Maximum load on house wiring for the day 300W

 

[BritManToo]

Finished rewiring, today.

And tomorrow adding a car charger socket with breaker in the car port, and fixing the 3 holes in the ceilings.

Total 7,500bht

 

I guess it could have been worse.

[Schoggibueb]

OK, sounds nice, but when you have melted insulation on wires there are not so many possibilities.

Couls it be that you have too small dimensioned wires for what is consumed?

Please check what you have and compare with the screenshot.

 

A1 & B1: Single wires in tubing underneath in brick / concrete wall

A2 & B2: Cables in tubing underneath brick / concrete wall

 

The expression "n Stromkreise" means one phase only

Sorry for the screenshot in German language. But as a swiss (retired) technician I use apps what are easy to handle for me.

 

 

 

[Schoggibueb]

P.S.

Check your light switches too. They might have burnt contacts. If you see or smell something, just change them. And get products wich can switch up to 16A (if your breakers have that).