Exposed wire: safety precautions when working with it
We all know that if you touch a bare live wire, it is fraught with the most dire consequences, even several hours after the incident.
Therefore, you should be wary of such wires. But what to do if it is in your apartment or house? After all, bypassing it is not an option, and this malfunction needs to be fixed. This is exactly what we will talk about in our article.
- Options for dealing with damaged wiring and solutions Unknown damaged wire
- Damage to the wire after a short circuit
- Wire damage during construction work
Zero break, zero burnout - consequences!
Rating: 5 / 510Zero breakage, zero burnout - consequences!
"What doesn't kill us makes us stronger." Controversial statement.
It definitely cannot be classified as electricity, because the effect of current on the human body depends on a huge number of factors, from body temperature to the presence of diseases.
Of course, no one is immune from being caught under voltage. But you can easily reduce the likelihood of such an incident. In this article we will tell you in detail about the break or burnout of the zero, the consequences of this, and protective measures.
As you know, three power supply circuits for electrical receivers are most widespread: triangle, star and star with zero. The first two are used mainly where the load is distributed evenly across three phases.
Advice
For example, the windings of electric motors or transformers are connected using such circuits. In residential and public buildings I use a “star-zero” connection scheme - a regular star with a neutral wire.
What is the reason for its use?
The fact is that in the residential and public sector the load is single-phase: one apartment (floor or private house) is powered from one phase, the next from the second, another from the third, then in the second circle. Since three phases of voltage are suitable for the input panel, the number of apartments in a house or entrance is a multiple of three.
This is an attempt to achieve uniform loading of the three phases. However, it is impossible to ensure that all apartments turn on and off electrical appliances at the same time. To keep the three-pointed voltage star (left) symmetrical, a neutral conductor is used.
Features of LED lamps
Someone immediately begins to think about the presence of a bad contact or some kind of problem with the chandelier. In fact, the reason lies in somewhat different circumstances. It should be sought in the design features of the lamp itself.
Energy saving lights or LEDs operate at 12 volts even though they are connected to 220 volts AC power. The voltage conversion process is carried out directly in the base part of the light device itself. It contains a diode bridge and a capacitor. Such a construction can be represented as follows:
Connecting lighting based on LED or neon bulbs has its own characteristics
Even if you remove the load on the supply circuit, microcurrents continue to exist in a certain amount. There are very few of them, but this is quite enough for the capacitor to accumulate a certain charging value.
It will be enough to “start” the lamp. The light source will be lit. But there is too little of it to supply enough power for the glow. Therefore, the glow quickly stops. The light source will attempt to “ignite” until the capacitor is discharged. When observing a similar phenomenon, they say that the lamp “blinks.”
There are cases where, after being turned off, the lamp begins to glow dimly. This effect is explained by the presence of insufficient resistance in the filament circuit. Such a circumstance will lead to a situation in which only a small amount is supported when charging the capacitor element.
What to do in case of a wiring fire?
If the apartment smells of burnt wiring, you notice smoke or an open fire in places where wires run or connect, or on electrical appliances that are turned on, you must take the following measures:
- Turn off the electricity, preferably at the input circuit breaker, in order to ensure a simultaneous break in both phase and zero. Without this, there is a high probability of electric shock in case of fire.
- If possible, protect the source of the fire or localize the fire. Under no circumstances should you touch hot elements to prevent burns.
- If there is a fire, begin to extinguish it.
If for some reason the operating conditions of the electrical wiring do not allow it to be de-energized, then the wiring must be extinguished using special means that do not conduct electric current.
Methods for extinguishing burning wiring
A short circuit is a fairly powerful impulse that can destroy the network. It appears when connecting the wires of a circuit, provided that the current does not reach the consumer. Afterwards it heats up and if measures are not taken, a fire occurs. If you see sparks, flames, smoke, and understand that the wiring is on fire, you urgently need to turn off the power to the room. They do this through the shield, but if there is no access to it or it itself is the cause, the current supply is stopped mechanically. This requires a tool that has electrical insulation. It could be the same axe. If it is not possible to extinguish the fire, you need to call the fire brigade immediately.
Similar: Press pliers for crimping wire lugs
It is forbidden to extinguish burning electrical appliances and anything connected with electricity with water, even sea water. This is due to the fact that water is a conductor and quite powerful; when extinguishing, you can get an electric shock. Water can be used in cases where the network is already de-energized and the wiring needs to be replaced.
In principle, during a power outage, any method of fighting fire will do. But if the network is live, only a class E (powder) fire extinguisher, which specializes in extinguishing fires of this type, is suitable. The maximum threshold for such devices is 900 Volts. If a fire breaks out in a network with a much higher voltage, the first thing you need to do is de-energize the network. Other devices, including foam ones, cannot be used - they will only aggravate the situation.
Bottom line, there are two ways to deal with an electrical fire using a fire extinguisher:
- Powder class E (can be used on any electrical appliances).
- Carbon dioxide, which is capable of operating with voltages up to 1000 V.
But which fire extinguisher to extinguish electrical wiring depends on several factors, including voltage.
The second reason
When wondering why a fluorescent lamp blinks, one cannot rule out a reason such as a zero interruption. In this case, during operation of the lighting device, a phase constantly flows to it. Zero appears only after the light bulb is turned on.
Solution
To correct the situation, you simply need to reconnect the phase and neutral. To do this, you need to establish where exactly the interrupt occurs. There can be two such places: an electrical panel in the entrance or a distribution box in the apartment. Before reconnecting the wires, you need to make sure that when you turn off it is the zero that opens, and not the phase.
To perform this action, you need to touch each wire one by one with an indicator screwdriver. If the neutral wire does not show voltage when the lights are off (the screwdriver indicator does not light), then this is where the reason lies.
To solve the problem, you need to reconnect the wiring to the switch from the panel or distribution box. This can be done in two ways: swap the zero and phase or run new wires.
Consequences of a short circuit
In the event of a short circuit, the circuit breaker must trip. This is usually what happens. And if not, then the wiring quickly overheats, melts and begins to burn. Therefore, short circuit is one of the most common causes of fire. A corresponding warning is also available on the website of the Ministry of Emergency Situations. According to this resource, every day in Russia 125 buildings burn down due to faulty wiring.
Fire due to shorted wiring
Sudden load fluctuations
A large number of modern instruments and devices, constantly connected to the network and operating in a certain mode, sometimes cause a significant increase in load. They usually don't last long, but at some point they can become critical. Why is this happening?
Modern electrical appliances are much more economical than old household appliances; almost all of them are class A or even A+. But there is one feature - there are many of them and some of them work automatically. They either connect and consume energy, then go into sleep mode and take the minimum from the network. There is a TV in one room, a computer in another, an economical refrigerator hums quietly in the corner, an energy-efficient dryer dries mushrooms, a modern low-consumption air conditioner cools the air, a washing machine does the laundry, and then an A+ class electric boiler started heating the water and the multicooker turned on at a high temperature. your program. At some point, the load may become critical for the home's electrical network.
Short Circuit Detection Techniques
If the circuit breaker has tripped, then the worst has been avoided. Then the question arises of how to find a short circuit in the apartment wiring. There is no need to panic. There is a chance that you will be able to detect the malfunction yourself without calling a specialist. Finding a short circuit in an apartment is divided into four simple steps:
- Visual inspection.
- Elimination method.
- Detection by sound and smell.
- Use of special measuring instruments.
Visual inspection
It is not a fact that the short circuit point is in the wall. Usually the fault lies on the surface. It can be seen with the naked eye and quickly eliminated.
Extension cords need to be inspected. Especially in places where the cable bends and the plug is connected. Often one wire comes loose and dangles in the air. A phase contact that is not secured by anything can touch the neutral contact and lead to a short circuit. Next are the sockets. Wires can also fall off and end up in the wrong place.
Visual inspection of electrical wiring in a private house
Elimination method
If a simple inspection does not help, you will have to move on to the elimination method. The main thing is to understand why the machine is triggered. It is worth remembering under what circumstances the short circuit occurred. If the embarrassment occurred at the moment when the iron was plugged into the socket, then the problem lies there. If not, you should turn off the household appliances one by one until the circuit breaker stops tripping.
If absolutely all devices are unplugged and the lights are turned off everywhere, then you will have to move on to the next stage. It is important to remember to check devices that are always plugged in (refrigerators, televisions).
Additional Information. You will never find a short circuit that is not there. Old circuit breakers are prone to false trips. That is, there is no short circuit in the wiring, and the machine lives its own life and turns off the apartment for no known reason. Before searching for a short circuit, it would not hurt to make sure that the protection devices are operating adequately and find out for sure why the circuit breaker trips.
Sound and smell detection
When a short circuit occurs, a lot of energy is released. She doesn't leave without a trace. Often in the problem area the wires heat up, the insulation melts, smoke is formed and there is a smell of burning. If the circuit is unstable, then when voltage is applied at the short circuit point, a bright flash with sparks and a bang will occur. Its intensity is such that it is almost impossible not to notice this phenomenon even in hidden wiring.
This and the previous methods require periodic re-switching of the voltage. This, in turn, will lead to a short circuit again. It is advisable to carry out such experiments a minimum number of times and with at least some knowledge and experience of such work. If possible, it is wiser to call a professional electrician. He will most likely come with a multimeter or megger.
Use of special measuring instruments
The method requires electrical engineering education. The closure point is sought using measuring instruments:
- multimeter;
- megohmmeter;
- indicator screwdriver;
Checking electrical wiring using a multimeter
These devices allow you to ring the apartment's electrical network and determine in which area there is a point with an abnormally low resistance between the phase and neutral (ground) conductors. The most effective way to find short circuits is a megohmmeter. But it is much safer to use a multimeter in diode testing mode. If a section of wiring with a short circuit is connected to its terminals, the device beeps.
