Question: Electrical Problem

[fittobethaied]

I purchased a new home in 2011, and I have never had a problem with the electrical system until now. For the past few weeks, anytime I am running my 2 a/c units and my wife, or myself, is taking a shower with the hot water heater going, the main shuts off. We have to turn off 1 a/c and flip the main switch back on to complete the shower. Any suggestions on what the problem could be? Any advice would be appreciated. 

[johng]

Put the shower and 2 AC units on separate breakers/fuses..that might require running new separate cables to each appliance.

[Crossy]

Could you post a photo of the distribution board with the lid off (care please)?

 

We need to see what you have.

[novacova]

37 minutes ago, fittobethaied said:

I purchased a new home in 2011, and I have never had a problem with the electrical system until now.

Since it’s a recent issue, might be due to a faulty appliance or a short, it would be advised to make sure there’s no issues there first. Would inspect the a/c’s and make sure they’re clean the boards aren’t hot and the compressor fans aren’t dragging. And don’t mess with electrical stuff if you’re not sure what you’re doing.

[fittobethaied]

4 hours ago, Crossy said:

Could you post a photo of the distribution board with the lid off (care please)?

 

We need to see what you have.

The 2 A/C's and shower heater are all on separate breakers. 10 breakers are being used, and two are not being used. And, I promise I won't be messing with it because I don't have a clue about electrical wiring. 

[couchpotato]

Had a similar problem last year. It was the water heater tripping the breaker, so as you have a separate hot water heater, that is more than likely your problem. If its the same heater since 2011, then I would just replace it anyway as its way past its due date. 

[Crossy]

How big are your A/C units (BTU) and your water heater (kW)?

 

To be clear it's the big blue breaker on the left that's tripping not the red one?

 

If this is the case, and this being a 63A breaker, initially I'd be tending to think it's a faulty breaker tripping early.

 

 

 

[BritManToo]

5 hours ago, fittobethaied said:

I purchased a new home in 2011, and I have never had a problem with the electrical system until now. For the past few weeks, anytime I am running my 2 a/c units and my wife, or myself, is taking a shower with the hot water heater going, the main shuts off. We have to turn off 1 a/c and flip the main switch back on to complete the shower. Any suggestions on what the problem could be? Any advice would be appreciated. 

I had a similar problem last week.

All the wiring from the fuse box to the ceiling box had melted in the trunking, in the wall.

No burning smell at all, but all had melted when the electrician pulled them out.

 

I asked why,

Electrician said original wiring used wire with substandard insulation, lasted 12 years then burned.

 

Good luck!

[wavodavo]

On 7/25/2025 at 11:52 PM, BritManToo said:

I had a similar problem last week.

All the wiring from the fuse box to the ceiling box had melted in the trunking, in the wall.

No burning smell at all, but all had melted when the electrician pulled them out.

 

I asked why,

Electrician said original wiring used wire with substandard insulation, lasted 12 years then burned.

 

Good luck!

You are lucky it didn;t burn your house down.

[Shutterbug Guy]

Get a qualified electrician to check it.  I had a similar problem, and it turned out that the main breakers were faulty.  I had the electrician completely replace both breaker boxes, and all is well now.  I even had him run a separate circuit to a refrigerator that we had added as extra insurance.  

[wavodavo]

On 7/25/2025 at 11:52 PM, BritManToo said:

I had a similar problem last week.

All the wiring from the fuse box to the ceiling box had melted in the trunking, in the wall.

No burning smell at all, but all had melted when the electrician pulled them out.

 

I asked why,

Electrician said original wiring used wire with substandard insulation, lasted 12 years then burned.

 

Good luck!

A few years ago in Australia there was a big stir when electrical wire from china that was sold by Bunnings and others was inferior and suffered the same problem with the insulation.It all had to be replaced as not up to AU standard and dangerous.

[BritManToo]

1 hour ago, wavodavo said:

You are lucky it didn;t burn your house down.

Poured concrete walls around the electrical trunking, nothing to burn.

[ross163103]

2 hours ago, Shutterbug Guy said:

Get a qualified electrician to check it. 

A Farang electrician if you can find one!

 

I've had some serious issues with Thai electricians. You don't want to get shocked, have your house burn down, or die because of someone's faulty work. Electricity is no joke!

[Jing Joe]

On 7/25/2025 at 11:11 PM, Crossy said:

How big are your A/C units (BTU) and your water heater (kW)?

 

To be clear it's the big blue breaker on the left that's tripping not the red one?

 

If this is the case, and this being a 63A breaker, initially I'd be tending to think it's a faulty breaker tripping early.

 

 

 

Crossy is on track in asking for  the Kw rating of the heater and>  is it the blue mains breaker? or the red Earth leakage C/B? and> if its the main breaker it could be hot from nearly overload and/or> tripping early being faulty. But consider this >     If the water heater is perhaps  6kw then the  current would be  peaking/cycling  at 25 Amps (some are as high as  6,8kw rating) and hopefully the house wiring being used is not just typical 10Amp, and youve also got some pretty serious C/B on the right so the total amps could be stretching the friendship on the 63 Amp  blue mains breaker, even if its not faulty to be  "tripping early".   The very nature of the water heater element construction may have small electrical leakage and be intermittently tripping the red one?, Perhaps not since you havent reassured us about which one> Blue/red?

If your water heater model is excessive in power rating?, consider replacing with as low as a 1.8 kw model?  especially for being kind to the house wiring as well as "avoiding" the tripping. (see below.)       If the installed unit is too high powered, even though the temperature setting is just right for you, it is surely cycling full on then off etc, and the on cycle means a high a current and could  be the culprit adding to when the a/cons are possibly cycling on/off too.  Regardless of their nominal Kw rating, the start current of their compressors are typically  6 times (momentarily) their running current,  and adding them up (when they coincide) will surely trip the blue mains C/B.        Be aware about the A/Con stated ratings. Sure there is the electrical k/w rating, but they often proudly boast the Kw heat/cool rating (like a  BTU rating) which is about 4 times the actual electrical rating because of the COP. Coefficient Of Performnce, i.e. the efficient ability of evaporation of the refrigerant to transfer British Thermal Units of energy from outside to inside of house or viceverca. The electrical k/w rating is the go but there are the peaks as above.

Hope this helps your chosen, thinking, electrician and do let us know red or blue, and the size of the water heater hey. 

 

[Jing Joe]

I forgot to add that if its only been happening lately like you said, it puts more suspicion on the water heating element being electrically leaky which is more likely to trip the RED earth leakage circuit breaker or residual as sometimes called. 

It only needs a small current to do this but again:- thats the red breaker.

FWIW, It trips the ELCB when a small current passes from the faulty heater element to its  case, then to the metal unit and via a good earth and not via the person in the shower to earth.   If the unit wasnt earthed, with a wire or even copper pipes,  the person could get quite a shock that would surely trip it and be saved from more shock.

 

[Jing Joe]

On 7/25/2025 at 10:32 PM, couchpotato said:

Had a similar problem last year. It was the water heater tripping the breaker, so as you have a separate hot water heater, that is more than likely your problem. If its the same heater since 2011, then I would just replace it anyway as its way past its due date. 

 

Agree Couchpotato, its getting on a bit. But was yours actually tripping a mains circuit breaker or the ELCB?  I'm trying to understand how the heater would have too high a current without showing signs like shorting, sparking or other major stuff.

Just thinking. 

[BritManToo]

54 minutes ago, Jing Joe said:

I forgot to add that if its only been happening lately like you said, it puts more suspicion on the water heating element being electrically leaky which is more likely to trip the RED earth leakage circuit breaker or residual as sometimes called. 

It only needs a small current to do this but again:- thats the red breaker.

FWIW, It trips the ELCB when a small current passes from the faulty heater element to its  case, then to the metal unit and via a good earth and not via the person in the shower to earth.   If the unit wasnt earthed, with a wire or even copper pipes,  the person could get quite a shock that would surely trip it and be saved from more shock.

 

Wires burning in the walls, they heat up expand then touch ...... the breaker flips off.

Then when you turn the breaker back on, they heat up in the wall, expand then touch.

Until eventually, they have melted enough to touch all the time and the breaker is always off.

 

Can't smell anything as the trunking is fairly air tight.

[OneManShow]

I used Schneider breakers/breaker box (more long term reliable brand) All main wire connections are "soldered" to resist rust, spark free (avoid resistance at connection points). 
Turn off the main and check for loose wire at breaker box (loose breaker screws of ACs and water heater. water heater connection pint as well). 
 

[emptypockets]

1 hour ago, OneManShow said:

I used Schneider breakers/breaker box (more long term reliable brand) All main wire connections are "soldered" to resist rust, spark free (avoid resistance at connection points). 
Turn off the main and check for loose wire at breaker box (loose breaker screws of ACs and water heater. water heater connection pint as well). 
 

When you say soldered...I sincerely hope you don't mean the cable ends that are screwed down into the breakers. Solder ' creeps' and can lead to hot joints.

[OneManShow]

2 hours ago, emptypockets said:

you don't mean the cable ends that are screwed down into the breakers

No 

Connecting outlets above walls. By US code outlets must be connected one after another (outlet to outlet), but here electricians connect outlets to a common wire (to breaker box) above walls. (Fire hazard). I solder wires from outlets to common wire to prevent sparks and rust. Just a little solder at the twisted connecting point will secure connections and no need to be a chunk of solder.

[Jing Joe]

14 hours ago, BritManToo said:

Wires burning in the walls, they heat up expand then touch ...... the breaker flips off.

Then when you turn the breaker back on, they heat up in the wall, expand then touch.

Until eventually, they have melted enough to touch all the time and the breaker is always off.

 

Can't smell anything as the trunking is fairly air tight.

 

Mmmm, you could have a point there but more often when wires touch, a minor  arc  causes welding of the 2 copper contact points? or worse still the melting copper leaves too wide a gap to possibly touch again and theres an open circuit anyway??  Just thinking. What do you reckon?