Appliances blowing up. When is a power surge not a p surge?

high resistance, low capacity or intermittent neutral circuit.

The electric went off at 9pm last night. There was a strong burning smell coming from the new refrigerator before we unplugged it. We were only using three items at the time: the new fridge which only draws 110 watts, 1 AC and a couple of lights.
Before this week we use to running everything in the house at the same time including both air conditioners and never had this issue before .
What I found: The fault is not in the power circuits as they never trip. It’s in the neutral circuits . The neutral circuits are intermittent due to high resistance somewhere between the pole and the 110 plugs in the house. When the neutrals are bad the 110v circuits look for other paths to ground which can double the voltage on those circuits. I have measured the 110v circuits in the house during one of the neutral line failures at over 200 volts. This is why so many appliances have been damaged. The 110v breaker has never tripped because the amount of power being used has never reached 20 amp, the capacity of the breaker . Despite this, the power in use is just enough exceed the capacity of the neutral wire because of higher than normal resistance on that line back to the pole. While there are visible taped neutral line connections between the plugs and the pole, I believe the neutral issue is in the 3P 220v main breakers (neutral pole). It’s original to the house . Resetting that breaker restores the neutral connect but the power circuits were never tripped and all AC continued to operate though out the issue. They are 220 an are not dependent on a neutral line to comment Pete the circuit. This tells me the neutral pole of the breaker is tripping at lower amperage’s than the breaker is rated for. The issue is temporally fixed when the 3P breaker is reset.

While the issue appears to have fixed itself, I believe it’s only temporary. When I reset the 220v breaker last time I didn’t first un-plug everything on the 110v circuit. (110v breaker runs off the neutral suppled by the 220v breaker) .The high current must have overheated the neutral circuit at the point of the high resistance and cause the connections to weld tightly together , lowering the resistances in the circuit. Don’t where that occurred in the breaker contacts or in some taped connections. At this point the neutral line is carrying the full circuit load. I’ve also purchased surge suppressors for all my vulnerable appliances so they don’t cook the next time the neutral line crashes. I’m sure it will eventually I can’t afore to fix or replace them a third time.

I use these plug in GFCIs for all appliances I care about. It might’ve saved my laptop from being fried one day that it tripped. Although it also could’ve been a spurious trip, it’s hard to know.

ELI5, please. Diagrams would help.

If you got a 3P mains breaker, you have a 3 phase supply.

That means your 110 isn’t coming from the supply at all but rather supplied by a transformer. It looks something like this:

So if you got a fault to neutral, look and see what is between your appliance and this thing. The center tap goes to this transformer. I suspect bad connections…

My apologies either the ISP or the site is sending my replies to all of you, back to me. :confused: I don’t have any diagrams but here is a picture of the 110v circuit carrying a 220 charge.

Starts out at 110v then climbs to over 200v on a 110v line when the neutral wire/connect fails. The power breaker never fails which is the biggest part of the issue. They use a 3p breaker on a 220 circuit because they want the neutral to trip as well as the power . Not only is this not happening, The power is doubling on the 110v circuits because the neutral on the 220v 3p breaker is failing to hold the load. Trying to explain this to anyone appears to be fruitless. Even my landlord has been out and he’ s suppose to be some kind of electrician. he said just ignore the flashing lights, there isn’t anything wrong. It’s hard to argue with the pictures showing the 110v circuits carrying 220 volts. This is also a huge fire and electrocution danger. Anyone who touches a 110v appliance energized from half a 220v main breaker with no neutral and a poor to non-exsistant ground is liable to light up like a Christmas tree.


An Update
While none of the answers actually helped, that’s because the panel was wired incorrectly (non-standard) to begin with. I made the assumption since I’m new to Taiwan that it was wired to code. My diagnosis was still correct however. After the breaker was removed I took it apart and the center tap was indeed burned out and the power taps were good. The landlord was using a three phase breaker on a two phase system and running the neutral wire through the center tap. This is a better method as the neutral gets cut when the breaker trips preventing electrocution through back feeding then neutral wire with current. While it’s a good idea, that’s not how things are done in Taiwan. Confused? So was I. With the bad neutral in the breaker, as the current load increased the neutral would drop out leaving the power circuits live. The breaker would not trip because the current on the circuit had not exceed its rating 40 amps. This deprived the 115 circuits of their path back to the pole so they found their own path through ground and started putting out 240 volts to all my 110 appliances. Not only did this fry several of them but it created a major Electrocution and fire hazard in the house.
I saw an electrician working on a house up the street and asked him to replace the three phase breaker with a new one . While he didn’t do what I asked (language barrier) he did understand the issue and had a fix. He took out the three phase breaker and put in a two phase breaker and tied the neutrals wires together. More like the norm in the US and apparently in Taiwan as well. It’s Been working for a month, all is good !


Yea that was done wrong. 3 phase breaker is used with 3 phase supplies. You aren’t supposed to use a switch on neutrals at all. Switching is only done on hot wires. So 3 phase breakers are supposed to have 3 hot wires.

I think your landlord should replace your broken appliance.

You are right but I like my landlord and don’t wish to move. I’ve never had an issue before and I’ve rewired most of the important (expensive) appliances anyway. Thanks for your reply.

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That’s the thing right there, this can be worth a lot more than a few appliances in the long run.