Argh!
We havea situation here: the electric installation in our flat goes somewhat crazy. It began with flickering lamps. Then, while switched on, they‘d begin to go dark in circles (one room after the other), or dimly light at a fraction of its usual brightness, and then turn much brighter for a short time.
Then my table-radio (a nice sony cmt-x5cd) literally went up in smoke!
Sad and frightening this is.
We havea situation here: the electric installation in our flat goes somewhat crazy. It began with flickering lamps. Then, while switched on, they‘d begin to go dark in circles (one room after the other), or dimly light at a fraction of its usual brightness, and then turn much brighter for a short time.
Then my table-radio (a nice sony cmt-x5cd) literally went up in smoke!
Sad and frightening this is.
Attachments
Move immediately, this is a terrible situation! That "much brighter" means the AC line is much higher than nominal.
Maybe your home insurance will pay for some of the damages. Or the landlord.
Maybe your home insurance will pay for some of the damages. Or the landlord.
Thanks rayma!
I already did as I concluded it a dangerous situation (radio burning out of nothing is not good at all). Took out the fuses, called electro-emergency, they had me just swap all of the main fuses (20A) of the flat, and all seems well but still it’s worrysome.
Will call electrician tomorrow.
@Galu no, „not today“. That is, the houselord (proprietary) said something like their fridge was out once and their lightbulbs blow too often, but this doesn‘t sound like our situation. Something with the flat‘s installation must be rotten i guess…
I already did as I concluded it a dangerous situation (radio burning out of nothing is not good at all). Took out the fuses, called electro-emergency, they had me just swap all of the main fuses (20A) of the flat, and all seems well but still it’s worrysome.
Will call electrician tomorrow.
@Galu no, „not today“. That is, the houselord (proprietary) said something like their fridge was out once and their lightbulbs blow too often, but this doesn‘t sound like our situation. Something with the flat‘s installation must be rotten i guess…
If you have 3-phase supply and neutral wire connection to the grid is faulty, than such problems will occur. Unless neutral wire is grounded, as in my house.
Once, neutral wire connection of my house burned on the electric post side. When electric company repaired it, they told us that grounded neutral wire in our house saved our electric appliances from damage.
Once, neutral wire connection of my house burned on the electric post side. When electric company repaired it, they told us that grounded neutral wire in our house saved our electric appliances from damage.
I read that an over voltage like yours can be due to short-lived oscillations caused by changes in the voltage and the current load.
Such oscillations can be produced by arcing between line and ground somewhere in a three-phase system.
http://www.electricalidea.com/over-voltage-due-to-internal-causes/
Now, I am not an electrician, so don't quote me or assume the above applies to your situation!
However, I hope your electrician is able to trace the source of your intermittent fault, whatever it happens to be.
Such oscillations can be produced by arcing between line and ground somewhere in a three-phase system.
http://www.electricalidea.com/over-voltage-due-to-internal-causes/
Now, I am not an electrician, so don't quote me or assume the above applies to your situation!
However, I hope your electrician is able to trace the source of your intermittent fault, whatever it happens to be.
I would refrain from using anything electric that is nonessential (except fridge etc.) until then.
Last edited:
If it's a loose neutral wire, you can get anything from zero to sqrt(3) times the normal voltage. When all phases are loaded equally, you get the normal voltages, but as soon as there is an imbalance, the light loads get too much voltage and the heavy loads too little.
Then again, when everything but one reading light is disconnected, that reading light shouldn't work. Maybe it's something else than a loose neutral wire then.
Then again, when everything but one reading light is disconnected, that reading light shouldn't work. Maybe it's something else than a loose neutral wire then.
OP lives in a flat. If few flats in the building shares same grid connection than everybody should disconnect everything else to stop that reading light from working if neutral wire connection is the problem.
I live in the States and had several adverse over-voltage events last year while WFH. I have National Grid, yes, there are here in America too.
I ended up buying an APS Double Conversion type UPS. Yes, it has a battery, but more over - it takes the mains AC and reconstructs a fresh AC output using active devices to insure frequency and voltage stability. This is very cheap insurance if you have expensive stuff - not just audio - but my home Wifi Router, my FreeNAS server and other things. Well worth the peace of mind. They are designed for Computer Servers - but for home electronics its great protection.
I ended up buying an APS Double Conversion type UPS. Yes, it has a battery, but more over - it takes the mains AC and reconstructs a fresh AC output using active devices to insure frequency and voltage stability. This is very cheap insurance if you have expensive stuff - not just audio - but my home Wifi Router, my FreeNAS server and other things. Well worth the peace of mind. They are designed for Computer Servers - but for home electronics its great protection.
Remembers me one situation years ago, where two Disco partners become enemies and one of them cut the neutral at the aerial connection during the night.
We spent the whole Saturday looking for the fault in the wiring, fuse boxes, etc. and only when the utility technician came the fault was found as how we suspected. We had luck that only a few ceiling halogen spots burned.
We spent the whole Saturday looking for the fault in the wiring, fuse boxes, etc. and only when the utility technician came the fault was found as how we suspected. We had luck that only a few ceiling halogen spots burned.
Yesterday, after swapping the flat‘s 20A main fuses, everything seemed back to normal (but I nevertheless disconnected all crucial stuff), and today things are just back in it’s weirdness.
Time for the pro to check things out!
This situation gives those warnings about electric circuitry (the header of the various forums here!) a whole new context, and I just realize how little (not measurable little) I understand of electricity/circuitry!
Time for the pro to check things out!
This situation gives those warnings about electric circuitry (the header of the various forums here!) a whole new context, and I just realize how little (not measurable little) I understand of electricity/circuitry!
Square root of three times the normal voltage, so about 400 V when the normal voltage is 230 V. It's the voltage between two 230 V lines that are 120 degrees out of phase.
With a loose neutral wire, that 400 V gets voltage divided by the loads on the three phases. That can lead to weird behaviour. For example, suppose all three phases are only loaded by exactly the same type of small lamp. The lamps will then work as if everything were normal. Turn on a vacuum cleaner on one of the phases and the lamp on that phase will almost turn off, while the other two get almost 400 V and burn out.
In the Swiss electrical system the power is supplied by an earth and three phase power supply with a common. There are three wires with voltage 120 degrees apart for each phase, a common wire and an earthed wire. Between any voltage wire and the common wire there should be 230 volts. Between any two voltage wires there should be 230 volts times 2 times .866 for the phase angle of 120 degrees. That is 400 volts.
The common wire is considered to have equal loads placed on it from all three voltage wires. If it is heavily loaded by two of the voltage wires the the common wire will have less voltage between those two wires and more voltage on the other. That is why the loads must be balanced.
I suspect you were told to replace all the fuses as the common problem is one is blown and that changes the balance.
I suspect the problem is a three phase motor of some large size is on the same distribution legs as your flat. I have a three phase motor that starts nicely but has a bad winding! So it draws current from all three phases when starting, lowering all the voltages, then one winding opens and it only draws power from two phases. That would cause the unloaded wire to increase in voltage except in the U.S. the common wire is also earthed and shares the loads with all the rest of the folks using electricity, so that even a 20 amp unbalance might not swing the voltage. However in practice there is some ground resistance. So a 20 amp imbalance would actually swing the open circuit by 26 volts worst code complying case.
I also used to have a neighbor on the same distribution transformer that drew almost all their power from just one leg. That also unbalanced the voltage a bit.
The easy fix is to see which wire is going up in voltage and not use any outlets on that phase! Easy to do. You know where the radio that became a smoke signal was plugged in. Remove your fuses one at a time and the one that provided power to the radio’s outlet is the circuit to avoid using until the problem is fixed. However some loads like a refrigerator do get unhappy running on low voltage!
The common wire is considered to have equal loads placed on it from all three voltage wires. If it is heavily loaded by two of the voltage wires the the common wire will have less voltage between those two wires and more voltage on the other. That is why the loads must be balanced.
I suspect you were told to replace all the fuses as the common problem is one is blown and that changes the balance.
I suspect the problem is a three phase motor of some large size is on the same distribution legs as your flat. I have a three phase motor that starts nicely but has a bad winding! So it draws current from all three phases when starting, lowering all the voltages, then one winding opens and it only draws power from two phases. That would cause the unloaded wire to increase in voltage except in the U.S. the common wire is also earthed and shares the loads with all the rest of the folks using electricity, so that even a 20 amp unbalance might not swing the voltage. However in practice there is some ground resistance. So a 20 amp imbalance would actually swing the open circuit by 26 volts worst code complying case.
I also used to have a neighbor on the same distribution transformer that drew almost all their power from just one leg. That also unbalanced the voltage a bit.
The easy fix is to see which wire is going up in voltage and not use any outlets on that phase! Easy to do. You know where the radio that became a smoke signal was plugged in. Remove your fuses one at a time and the one that provided power to the radio’s outlet is the circuit to avoid using until the problem is fixed. However some loads like a refrigerator do get unhappy running on low voltage!
Last edited:
Thanks a lot for all these explanations!
Problem was a neutral line not tightly fixed, which then got another getting hot…
See the earth wires cobbled together into 1 ! hole … ☠️ Incredible.
All but the radio is well again.
Problem was a neutral line not tightly fixed, which then got another getting hot…
See the earth wires cobbled together into 1 ! hole … ☠️ Incredible.
All but the radio is well again.
