What happens if you mix up the battery terminals? Installed on the car, and also when charging Why does the battery have the terminals mixed up by the manufacturer?

Until an unpleasant situation occurs, perhaps few motorists think about what will happen if the terminals on the battery are mixed up; moreover, most are sincerely surprised how such confusion can arise at all. In fact, no one is immune from it: sometimes the terminals can be mixed up in a hurry, but most often the mentioned incident happens at the time of replacing the car battery due to simple inattention to polarity.

Be that as it may, there is a problem. And it has its consequences.

What can result from incorrectly connecting the terminals to the battery on a car - 8 consequences.

1. Closure.

The first thing that happens in 100 percent of cases of polarity confusion is a short circuit. It is difficult to confuse it with something else: if electrical clicks are heard at the connection points, sparks fly out, perhaps even smoke starts, and the wires naturally heat up significantly, it means that you have mixed up the terminals. Immediately, turn off the ignition and disconnect the clamps from the battery as soon as possible; a lot will directly depend on your reaction at this moment - from the presence/absence of other problems to their scale and seriousness for the car.

2. Ignition/fire.

If the signs described above are ignored by you for one reason or another, you risk simply “burning” your car. Heated wires, especially thin ones, quickly melt, their braiding ignites, and given the fact that there are flammable liquids (gasoline and oil) nearby, the risk of a car catching fire in seconds is extremely high.

3. Decrease in battery power.

Even if you do not take into account the possibility of a fire, mixed-up terminals do not bring anything good. First of all, this concerns the battery itself, because it has a polarity - negative and positive plates, which, if the power is connected incorrectly, will tend to reverse polarity. If this process lasts for a long time, in turn, it will lead to shedding of the positive plates and, as a result, a drop in the power of the power source.

4. Failure of the electronic control unit (ECU).

Of all the possible (not counting fire) consequences, failure of the ECU can be called the most serious, because if the electronic control unit board burns out, nothing in the car will simply work: neither the windshield wipers, nor the direction indicators, nothing...

5. Burnout of fuses.

If you are lucky, you noticed your mistake quickly and just as quickly connected the battery to the car correctly, started it, and at first glance everything is in working order, do not rush to rejoice, perhaps the short circuit has hit nodes that are not yet visible to you. Check all the electrical functions of the car, you are probably lucky, but most likely there are fuses somewhere that have taken the increased load on themselves, so now that everything is in order, they need to be replaced.

6. Generator failure.

But the wires get confused not only in the car, but also at home, when charging, what happens then.

By and large, nothing happens in such cases. The battery always remains intact; the only thing that is at risk is the charger. Moreover, as a rule, he always remains alive, only his fuse burns out, which is easily changed.

Conclusion.

As you can see, with the exception of confusion when charging at home, incorrectly connecting wires does not bring anything good, so do not experiment and approach this process with all care and responsibility.

Stories of car owners.

Svyatoslav:

“Recently, in a hurry at home, I got confused with the wires while charging, indeed, everything was fine with the battery, but the charger had to be replaced: there was some kind of cheap charger, there was no fuse in it, so it burned out completely, but the main thing is that the battery is fine.”

Sergey:

“I don’t know how you can wait 1-2 minutes when lighting a cigarette, as soon as I touched the second terminal on the donor car, it sparkled so much that the thought of completing the connection did not even arise, they quickly turned everything off and reset it, only then did they realize that there was something wrong with the polarity got it wrong."

Vlad:

“Fuses are always the first thing to look at, not only when everything seems fine, but also when the car won’t start. They are the first thing that flies when the terminals are confused.”

Konstantin:

“I was always surprised how people can mess up terminals, but last week I encountered this myself - I installed the battery late in the evening, when it was already dark, and so I got it wrong. As a result, the car stopped starting, although the starter clicked. I went through all the fuses, everything is fine, checked the generator and so on, in general, it turned out that the battery simply died... although the headlights turned on, it was clear that the power had dropped significantly.”

Video.

The question is: what will be the consequences if the battery terminals are mixed up? We will consider this topic, since novice car owners should know this information. It's hard to imagine that the terminals can be mixed up when installing a battery.

This can be done when charging the battery, especially in a hurry. It is much more difficult to do this on a car, because the terminals are of different sizes, but it happens.

So what will be the consequences if you mix up and connect the battery terminals incorrectly? To give the correct answer to this question, it is necessary to consider possible cases of such a connection.

Let's start with the easiest one according to the consequences of the case, this is when the clamps that connect the charger to the battery are mixed up. The chargers do not have terminals with different sizes; they are quick-detachable, and it is easy to confuse them. Factory-made chargers will react to this by blowing the fuse.

Homemade chargers may not have such protection, but a sign of an “accident” can be given by the strong hum of the power transformer. If such an error was quickly eliminated, then there will be no special consequences for the battery.

It will be much worse for him if he continues to “charge” like this for some time. In such cases, a process occurs in the battery that experts call reversal. It harms the battery, reducing its service life, but it is possible to correct the situation a little. To do this, you need to completely discharge the battery using a car light bulb (preferably from a brake light). After this, having correctly connected the charger to the battery, it is fully charged.

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What happens if you mix it up?

What are the consequences if you mix up the battery terminals on a car?

Several connection options and their consequences are possible.

The terminals are mixed up when installed on a vehicle with the engine running;
The battery is installed with the ignition off.

First point will cause much more trouble to the driver than the second one. When changing the polarity of the battery, it can be damaged, as well as other electronic devices of the car. This applies mainly to older cars that do not have factory protection against incorrect battery connection. Most modern generators are equipped with electronic relays that control battery charging, for which polarity reversal is unacceptable.

If the battery is connected incorrectly with the ignition off, the consequences will be less severe. In this case, previously turned on electronic devices, watches and other devices usually come out. Sometimes blown fuses installed in their power supply circuit help out, but provided that they meet the necessary requirements for the maximum current in the protected circuit.

Possible faults

A battery left incorrectly connected for a long time can cause a fire. The same consequences may occur.

May also be harmed, if installed on the vehicle. This threatens a complete failure of all vehicle systems. It needs to be replaced, which will significantly “lighten” the owner’s wallet.

Negligence and inattention can damage your car alarm. She prefers to work only with her poles.

Be sure to pay attention to the wiring, and not just the one that comes from the battery. It happens that wires that were under load during connection melt and short out. Modern cars provide some protection against incorrect connection. A fuse is installed at the positive terminals.

We considered the question: What will be the consequences if the battery terminals are mixed up? Also, to prevent short circuits, electronic units are protected by diode bridges with fuses. The fuse blows, but the unit is in good condition. Do not be too hasty when installing the battery, it can literally be expensive.

Reversing the battery polarity when connecting is one of the worst things that can happen to a car.. According to the consequences, polarity reversal is on the list of misfortunes after fire and water hammer. The car won't start, won't drive - it needs a good electrician and possibly a lot of money for repairs.

The current in the “battery-switch-electrical appliance” circuit goes from plus to minus. The electrical wiring in the car is mainly “positive” wires connected from the device through a fuse, switch or relay to the positive of the battery and the diode bridge of the generator. On the downside, all electrical appliances (ECU, generator, light bulbs, radio, sensors) are connected through the body of the car. The entire body is the negative wire, and it in turn is connected to the negative of the battery / generator.

For example, for ordinary light bulbs it makes no difference in which direction the current flows through the filament, because this filament will always be a resistance in the circuit, limiting the current consumed. For example, through a 50-watt light bulb, no matter how you connect it to the circuit, a current of 4 Amperes will flow through the circuit.

For a radio, amplifier, and most electrical appliances and sensors that are more complex than an incandescent light bulb, incorrect connection is fatal. The circuitry of these devices assumes that they will only work when connected correctly. For example, if connected correctly, the ECU consumes a current of 2 A, and if connected incorrectly, a short circuit current of 1000 Amps will flow through it. If the connection is incorrect, some parts burn out within microseconds, the resistance decreases to zero, and a short-circuit current from the battery flows through the device. If there is a fuse in the circuit, it will blow, but unfortunately after damage to the electrical appliance itself.

A car battery is capable of delivering a short-circuit current of 1000 A -1500 Ampere!

Various possible consequences of polarity reversal are described on the Internet. Drivers who mixed up the polarity when connecting the battery ended up having to replace: fuses, diode bridge, generator, heater, radio, amplifier, ECU and a number of sensors. There is no special list: this will burn, but this won’t. The current will follow the shortest path and the least resistance. Current up to 1500 Amperes! Only a practical “experiment” can show which electrical appliances in a particular car will get in its way.

It is logical that a well-charged battery with a capacity of 100Ah is capable of delivering a powerful short circuit current through/to electrical appliances if connected incorrectly. In theory, fewer problems will be caused by incorrect connection of a discharged old battery with a capacity of 50Ah.

There will probably be fewer problems with cars in which the plus from the battery goes to the devices via separate wires through separate fuses and in which more than one or two wires go from the minus of the battery to the body. In theory, such an advanced battery connection scheme should reduce the short-circuit current in a single device and in case of incorrect connection of the battery. The likelihood of survival of electrical appliances increases.

Automotive electrical appliances do not have 100% reliable protection against polarity reversal, due to the impossibility of creating such an effective protection system!

Also, when organizing protection against polarity reversal, the difficulty is that the minus in the car is the hardware of the car (its body). Accordingly, if the polarity is reversed, the current will flow directly to almost all electrical appliances: radio, ECU, stove, light bulbs - through the housing. That is, bypassing switches or relays that until that moment opened or limited the current of the correct polarity. And when reversing the battery...

It has long been known from the practice of service centers that some customers can reverse the polarity of the battery in such a way that no protection will help.

The terminals in the car and the current terminals of the starter batteries are made of different thicknesses and diameters (foolproof). The negative terminal cannot be placed on the positive terminal of the battery - the positive terminal is thicker than the diameter of the terminal. The positive terminal is also marked with a red plastic cover. A red cap is placed on the positive terminal of the battery. The polarity of the battery current terminals is indicated on the case next to the terminals by the “+” and “-” icons. Designers, in order to prevent the car owner from mixing up the polarity of the battery when connecting it, complicate the process of self-replacement: covers, latches, air ducts that cover the battery from “tampering”. It’s safer and easier to replace the battery at a service center.

Maintaining correct polarity when installing the battery is vital for your car!

The most interesting case of reversed polarity was found on YouTube. The owner of the car turned to the service with a request to find out: why, after installing the battery, which he removed for recharging, the electronics and fuses burned out and the car stopped starting? The polarity of the battery was not reversed during installation. The positive terminal was put on the plus of the battery, and the negative terminal on the minus. But... as auto electricians found out, the battery itself was reversed when charging)

Be careful when servicing, replacing and even charging your battery, do not repeat the mistakes of others!

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This can be done when charging the battery, especially in a hurry. It is much more difficult to do this on a car, because the terminals are of different sizes, but it happens.

What happens if you mix it up?

What are the consequences if you mix up the battery terminals on a car?

Several connection options and their consequences are possible.

The terminals are mixed up when installed on a vehicle with the engine running;
The battery is installed with the ignition off.

First point will cause much more trouble to the driver than the second one. When changing the polarity of the battery, the diode bridge of the generator, as well as other electronic devices of the car, can be damaged. This applies mainly to older cars that do not have factory protection against incorrect battery connection. Most modern generators are equipped with electronic relays that control battery charging, for which polarity reversal is unacceptable.

If the battery is connected incorrectly with the ignition off, the consequences will be less severe. In this case, previously turned on electronic devices, such as a radio, clock and other devices, usually come out. Sometimes blown fuses installed in their power supply circuit help out, but provided that they meet the necessary requirements for the maximum current in the protected circuit.

Possible malfunctions if the battery is connected incorrectly

A battery left incorrectly connected for a long time can cause a fire. The same consequences can occur if you improperly light a cigarette from another car.

May also be harmed on-board computer, if installed on the vehicle. This threatens a complete failure of all vehicle systems. It needs to be replaced, which will significantly “lighten” the owner’s wallet.

Negligence and inattention can damage your car alarm. She prefers to work only with her poles.

How to determine: phase, zero and ground

For two-wire wiring:

Important: When determining the phase in the wiring of a house or apartment, it will be necessary to apply voltage to this same wiring. In this regard, subsequent work and experiments become unsafe for life. Therefore, think 100 times whether you need this; it may be better to call a professional electrician who has a permit. Life is much more valuable than the money he will take from you.

If you were indifferent to my warnings, then let’s move on and read point by point, like two wires determine where the phase is and where the zero is.

1. Unplug all appliances.

2. Turn off the power to the apartment or house; the voltage should be turned off completely.

3. Expose the two wires with which you are going to “sort things out.”

What happens if the support bearings are reversed?

I don't mean that you need to completely remove the insulation from the wires, just that their ends should be slightly exposed and stripped, and also be at a distance from each other so that they do not accidentally touch and a short circuit does not occur.

4. Apply voltage again, including to the wires you need.

5. Take an indicator screwdriver. If you don't have it, then you need to buy it. It costs a ridiculous amount of money, like a loaf of bread. Therefore, there is no need to look for other methods and say that: “I don’t have any screwdriver, maybe a light bulb would be better.”

6. The indicator screwdriver should be in the right hand. You only need to take it by the dielectric handle. Touch the end of the screwdriver to each of the wires in turn. In this case, the index finger of the right hand should be placed on the tip of the handle, which should be metal.

The wire on which the indicator lights up is phase, and the second wire, naturally, is zero.

This entire instruction is very suitable for two-wire wiring, but there can be 3 wires, that is, zero, phase and ground.

For three-wire wiring:

You can determine the phase in a three-wire wire in exactly the same way: the indicator will light up. The indicator screwdriver will not respond to ground and zero.

Zero and ground are defined differently in different cases. Some determine by the colors of the wires: brown - phase, blue/cyan — zero, green yellow/striped - Earth. However, in this case, you need to rely on electricians who should not have mixed up and used a specific color for a specific wire. That's why this method is immediately eliminated.

You can take a socket with a light bulb and two wires, screw one to the phase determined by the indicator, and with the second touch the two remaining wires in turn: where the wire lights up is that wire and zero. However, the light bulb may also light up if it comes into contact with earth. You can measure the voltage one by one using a voltmeter. In a phase-zero pair, the voltage must be greater than in a phase-ground pair.

Tips on how to find out 0 and ground:

1. Climb into the shield and turn off the protective grounding. On the remaining pair of wires the load (lamp) will work. This is if you know exactly where the ground is in the shield.

2. Close the phase to one of the remaining wires. If the plugs are knocked out, then zero. If not, then the ground. Provided that you have plugs and you are not afraid that all the wiring will burn out. And it's quite dangerous.

3. There are special indicator screwdrivers with a battery, IEK sells the same ones (these yellow ones), so it’s convenient to distinguish the ground from zero. We identify the neon phase, turn off the packet/input machine (this only works if it is bipolar), poke the remaining ends, the one that lights up is ground, the one that doesn’t light up is zero.

4. Using an AC voltmeter, measure the voltage between the unidentified wire and the heat supply battery (pick off the paint and touch the metal). The “grounding” wire will have zero potential, the “zero” wire, due to phase imbalance (different phase loads), the potential can be from zero to 20-30 volts.

5. If you have a three-wire network, then there must be an RCD, then determine the phase wire, having first disconnected the entire load (i.e. it should not be shorted anywhere on the devices). After determining the phase and connecting to it (for example, an incandescent lamp), connect the second wire to any of the remaining wires (make all connections with voltage relief), turn on the RCD, then turn on the input circuit breaker, if the RCD does not turn off, then the second wire is zero, and if the RCD turns off, then this is a protective grounding.

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Hello, there is a need to connect a hob instead of the old stove after renovation. What remains from the old plate is a terminal block with 3 wires (phase, neutral, ground), but from the point of view of the tester, there is a phase and two zeros. 🙂 Question: 1. how to determine who is zero and who is grounding? 2. How important is it not to confuse them? (I suspect that in the 504 series house there is no separate grounding and these wires are connected in the panel to a common zero bus. Thank you.

Savin Alexey Nikolaevich 4 years, 7 months ago

Connect these two wires with the heating radiator, the one that shows less resistance is ground, if the resistance is the same, then there is no difference, you can set any wire to zero.

Eliseev Eduard Mikhailovich 4 years, 7 months ago

Most likely, this is the case. To do this, you need to open the shield and determine by the color of the wires from your stove which one sits where (on the ground or zero). And 3 wires are good if you install an RCD on the stove (electricians know this).

Eremenko Dmitry Alexandrovich 4 years, 7 months ago

there was no land in Savdep, zeroing was used if the automatic machine was not installed. then without limiting which wire to use as ground

Trifonov Andrey Sergeevich 4 years, 7 months ago

Take a tester and check for voltage, between zero and phase it will be about 220V.

Karpov Vyacheslav Nikolaevich 4 years, 7 months ago

He asked himself, he answered himself.

What happens if you mix up the battery terminals?

Determine by cable color. Whether they connect or not, look at the shield.

Kuskov Dmitry 4 years, 6 months ago

If the wires are the same color, then the ground zero should be slightly longer than the working zero and the phase wire. And if an RCD is installed on the hob, then if the zero is confused with ground, it will work. By the way, if you connect the VP not to the working zero, but to the protective zero, part of the current will go past the meter. You can get a hat for this.

Ermolaev Vadim Petrovich 4 years, 6 months ago

IT WAS TOGETHER IN THE SCOOP... YOU NEED TO CHECK ASAP THERE IS NO DIFFERENCE... AND THERE ARE SAME COLOR - WHITE... AND THE COUNTER CAN'T BE FOOLED SO... THE JUMPER IS AT ZERO... PURE POWER SUPPLY TO THE VOLTAGE COILS... ONLY PHASE TERMINALS MATTER

Dear visitor! You are in the archive of the old forum on mastergrad.com

change zero to phase (+)?

alladin Oct 14 2004 10:17:23	In the apartment, all light switches open zero, i.e. In theory, if you don’t turn off the machine and go to change the light bulb, it might shake. I don’t know who did this (the house is an old Stalinist one), maybe this was the custom before? The question is whether it is possible to simply take the shield and swap the zero with the phase, i.e. what was previously zero will become a phase. Do I risk burning something?
AndreyMax (Moscow, Russia) Oct 14 2004 10:33:08	Theoretically, you can burn it, But you can call and check before supplying 220V But if your neighbors have some tricks on your wiring, you can burn it. In general, only because of the light bulbs - it is suggested not to take a steam bath.
alladin Oct 14 2004 14:02:00	What does it mean for the neighbors to have feints?
AndreyMax (Moscow, Russia) Oct 14 2004 14:24:20	Well, maybe the ground wire goes further to them, or some of their sockets are powered. Maybe they have wiring from the ground to the battery... Of course it's unlikely - but who knows...
Crab (Moscow) Oct 14 2004 14:57:00	He can take a steam bath and switch the phases to zero on the breakout boxes. “...it’s troublesome, but it’s for the best...” Prof.Vybegallo
Rosta (Ryazan) Oct 14 2004 15:26:19	I think it is possible, if only you are 100% sure of your wiring. In old houses with two-wire wiring, they install sockets of a new type (Euro) with a ground contact, placing it on the neutral wire. Technically incorrect, but it provides some kind of “grounding”.
alladin Oct 14 2004 15:40:05	no, the earth weighs in the air in my shield What confuses me is that the machines are turned off section by section. 1. sockets 2. sockets 3. light in the rooms + old sockets 4. light in the bathroom and hallway + old sockets 5. washing machine (socket) + light in the kitchen This is such a zoo, I’m afraid it won’t let me in one phase at a time If you change it only in the shield, it will take too long and troublesome to move around the apartment.
Gennady B (St. Petersburg) Oct 14 2004 15:41:33	alladin! If you decide to “change the polarity”, check the wiring in the sockets. The connection in the socket, which Rosta reviews POSITIVELY, will play a tragic role in your switching!
ziv (Cherepovets) Oct 14 2004 16:14:07	Apparently in the "electrician" You can change the zero and phase at the entrance to the apartment. Perhaps they were simply mixed up somewhere in the apartment during renovations or something else.
ziv (Cherepovets) Oct 14 2004 16:15:26	Gennady B, I think his sockets are simple.
alladin Oct 14 2004 17:16:46	where I wrote “old sockets” - there are simple ones (without ground) Where there are sockets, there is earth, but it is all wired into the panel and is not yet connected anywhere (because there is no earth...) I just didn’t intend to change the machines for new sockets (No. 1, No. 2) but No. 3 and No. 4 would give up, No. 5 is questionable because there is a mixture of both new and old. Waved means that I pull the wire out of the machine and put it on the ground. From the ground, I plug a couple of this wire into the machine.
Rosta (Ryazan) Oct 15 2004 15:32:24
IS (Chelyabinsk) Oct 15 2004 16:30:51	to Rosta > > Check your ground wire for a short to zero in the apartment wiring. Since the house is old, there is most likely no earth wire there in nature. There are only two wires and God knows where the phase goes and where the zero goes. I wouldn’t be at all surprised if some of the switches break the phase, and some break the zero (although in this particular case the author of the topic wrote that all switches are made the same).
alladin Oct 15 2004 17:54:18	maybe not the same, but it’s easy to check I turn off the light and check with a tester whether there is a phase or not But I think that everyone is breaking zero.
amp (Moscow) Oct 16 2004 12:09:33	I thought only in my grandmother’s house (centre, 50s) such madness =) But no... maybe before it was really possible to break zero? At least, of course, if I bothered with any alterations, I would re-tighten all the wiring, install a normal shield and sockets with ground. Expensive, tedious, but right.
MaiklF Oct 16 2004 13:34:49	Naturally, an old house has no land. If you need to ground Euro sockets, you can use the “zero” only by laying this “zero” with a separate wire from the electrical panel. If the grounding contact of a Euro socket is connected to the WORKING “Zero” in the socket itself, this is not a buzz, and you should get rid of it (Otherwise, when an electrician, after some kind of repair, mixes up the input ends in the panel and places the neutral wire in a phase, the housing equipment connected to such an outlet will be under voltage. Voltage will also appear on the housing if the working neutral wire burns out somewhere in the electrical wiring). As for setting the switches to “zero”. As a rule, this occurs in old houses and villages. Once upon a time (I don’t know the exact date) there was a rule according to which it was forbidden to put switches on “phase” in order to protect the operator from electric shock in the event of a possible technical malfunction of the switch or the presence of moisture (water) in the switch. What happens if you mix up the battery terminals? Well, mistakes existed even in the PUE. Specifically in the case of alladin, I don’t see any problems. Elimination of mistakes with connections of switches is eliminated by the simplest switching of common input wires (for example, those suitable for its electric meter) in places. The neighbors have nothing to do with it. They have their own electrical wiring diagram - their own input ends and their own electric meter, respectively (unless, of course, we are talking about a communal apartment 🙂). And there will be no problems with sockets either, because... alladin writes that the grounding contacts are hanging in the air. And more about European sockets. A wire intended for PROTECTIVE “Zero”, i.e. to connect to the grounding terminal of a Euro socket, try to place it in the electrical panel separately from the common “zero” terminal (where the thread is further away in the panel, under a separate bolt/screw/nut). In order to protect your expensive equipment from accidental mistakes of a local electrician.
Alew (St. Petersburg) Oct 16 2004 16:39:19	MaiklF raised a question that is relevant to me: If an electrician mistakenly or deliberately connects a ground wire to a phase, how will an RCD and a two-pole circuit breaker react to this? And will they protect my expensive equipment? Thank you.
MaiklF 17 Oct 2004 12:26:27	If an electrician mistakenly swaps the phase with zero, then: - for a two-pole circuit breaker it is all the same, and it will continue to perform its main functions of protecting the circuit. - for RCD - it depends on the RCD model. For some, such switching is permissible and the device (RCD) remains fully functional, but for some it is not and the device (RCD) will not work. In any case, RCDs are not intended to protect equipment! THEIR goal is to protect a person from electric shock and protect the electrical circuit from fires associated with leaks due to violations of the insulation of live parts. Regarding the principle of operation of the RCD, I give a link where everything is explained briefly, simply and clearly: http://www.vashdom.ru/articles/ikm_uzo.htm By the way, a circuit breaker also cannot be considered as equipment protection (there are exceptions - an engine protection circuit breaker, for example). The machine serves to protect a circuit (electrical wiring line, for example) from exceeding the maximum permissible currents (usually in the event of a short circuit (short circuit), or when the permissible loads are exceeded, when an extra kettle is plugged into an outlet :)). Other devices are called upon to protect the equipment. - From power surges - stabilizers, for example. — Various types of filters for interference. - For uninterrupted operation of equipment - UPS (uninterruptible power supplies), as a rule, they have solid filters, and they perfectly save from voltage surges. - From watering equipment with water, when watering flowers - attentiveness and accuracy. - From breaking equipment, a toy thrown at it by a child - suggestion and a belt (for some), education is shorter. - Yes, from dust - a vacuum cleaner (by the way, a very necessary method of protection)
Margaret (Saint Petersburg) 17 Oct 2004 15:57:36	Can I ask a question from someone who doesn’t understand anything about electronics? If, after all, the ground in the socket is connected to zero, but everything is sourced. in the center of the city there is a “zeroed neutral” (according to electricians once), then what exactly will happen if someone changes something (connects the ground to a phase or something) in the common panel (everyone who can rummages through it) ? In some cases there is a surge protector, in others there is not. And what happens if the washing machine and electric oven are not grounded at all? For people and for technology?
IS (Chelyabinsk) 17 Oct 2004 17:41:56	to Margaret > > “zeroed neutral” (according to electricians once) Probably "grounded neutral"? So, in theory, she is grounded everywhere. > > what exactly will happen if someone changes something (connects the ground to a phase or something) in the common panel (everyone who can rummages through it)? In some cases there is a surge protector, in others there is not. If someone swaps phase and zero at the entrance to the apartment, you will get a phase on the body of all supposedly grounded devices. Those. touching a “grounded” washing machine and a bathtub or water supply pipes at the same time will be no different from sticking your fingers into a socket. > > It won't be a problem. True, the safety level will potentially be lower, but in practice this is not particularly important: previously, domestic washing machines had no grounding at all.
Margaret (Saint Petersburg) 17 Oct 2004 23:22:06	Thanks for your reply, IS. Of course, I wet myself, grounded neutral. The thing is that these words don’t mean anything to me (due to misunderstanding), I just repeat them like a parrot :). At the same time, we were always told that we did not have any land. It is also impossible to connect to the panel in the front door... So I'm trying to figure out what to do. Electricians from the housing office refuse to do anything for us (it’s a long story to explain why - in short, the residents of the house are arguing with the entire city administration, so we have continuous problems with small things - electricity, heating..), those whom we tried to hire clearly nothing They don’t understand, there’s no money for cool specialists... > > And what will happen if the washing machine and electric oven are not grounded at all? For people and for technology? > It won't be a problem. True, potentially the level of > security will be lower, but in practice this is not particularly > important: previously, domestic washing machines > had no grounding at all. What about warranty repairs of household appliances? Everywhere in the instructions it is written that, they say, we are not responsible for anything if it is not grounded. And what could still be, at least as you write, not terrible? How can this level of security manifest itself as a lower one? Can I get cheeky and have one more question? We also have an intermediate panel (that is, there is one in the apartment, there is a common staircase one, and there is an intermediate one for two apartments, although the second apartment has long been transferred to an office and what has been done for them is unknown). So, in it our (going to us) automatic machine (at 25 amperes) gets very hot, sometimes sparks if you turn on a lot of lights (this never happened before)… - besides the housing office electricians, can anyone fix this, otherwise it’s scary? (This machine sparked about 7 years ago, they called an emergency at night (then they still came to such calls, now they don’t), they replaced the machine with a spare one, which we had at home (for these 25 amps), as long as we had the machine before they didn’t specify then... Sorry for the abundance of questions, it’s just somehow scary to live... in St. Petersburg.
IS (Chelyabinsk) Oct 18 2004 08:41:42	> > That is, it is better not to connect the ground in the socket to zero at all? We have this only for computers. And a surge protector won't help? Rework sockets? It's better to have no ground at all than to have a connection in an outlet. A surge filter has a completely different purpose - it only catches voltage surges. quoted1 > > And we also have automatic machines (old models) set to phase and zero. They did this to us once. Is that also wrong? The machines must be double, i.e. so that when the machine is triggered, both wires would break simultaneously. > > So, in it our (coming to us) automatic machine (at 25 amperes) gets very hot, sometimes sparks if you turn on a lot of lights (this never happened before)... - except for the housing office electricians, someone can fix this, otherwise scary? This is what the housing office electricians do, and in the circumstances described, they need to be called urgently. They, of course, will dodge, but we must insist. If something happens, threaten to sue for failure to fulfill official duties.

For modern cars, this problem is irrelevant - the space under the hood is so tight that it is not convenient to put the terminals on the battery in the correct way. However, a person is only human to sometimes do impossible things unintentionally. You can buy the battery itself with the wrong polarity and put it in place of the old one. When lighting a cigarette, all cars have the risk of connecting the battery terminals incorrectly; in the dark or in a hurry, this may not happen.

Consequences of incorrect battery connection

Let’s immediately dispel the myth that a battery connected “backwards” starts the engine in the opposite direction. Let's start with the starter: if the stator has a winding and not permanent magnets, then when the polarity is reversed, the direction of the current will change simultaneously in both the stator and the rotor, the starter will begin to rotate in the same direction as before. Think about the commutator motors of electric drills, grinders and other tools - they operate on alternating current, the direction of which is constantly changing.

With permanent magnets on the stator it will actually start to rotate in a different direction, but the engine will not be able to turn over. Bendix will not allow force to be transferred in the “wrong” direction, that’s what it is designed for.

Even if you managed to spin the engine in the opposite direction, the four-stroke engine begins to take air from the exhaust manifold and throw exhaust gases into the intake manifold. So neither a carburetor nor an injection engine can be started this way, unless a diesel engine with a mechanical injection pump starts.

If the driver made a mistake during installation, then one of the most serious consequences will be that the generator will definitely suffer. Look at the diagram of its diode bridge (using the example of the simplest “Zhiguli” circuit):

A semiconductor diode is an element with one-way conductivity; it is not for nothing that its symbolic image looks like an arrow. It conducts current in the direction of this “arrow”, but not in the opposite direction. When the battery is connected correctly, while it is not working (the voltage on its windings is less than the battery voltage), the diodes are locked - for the battery, the generator is a load that consumes several milliamps due to the presence of a small reverse current in the diodes.

If you mix up the terminals on the battery, the diodes in the bridge will open and the battery will be short-circuited through them. This will lead to overheating of the diode bridge and failure of the diodes with a characteristic odor and popping noise due to the destruction of their cases.

Burnt out generator diode bridge

But polarity reversal is not always harmful for on-board electronics. Any electronic device, if it was not assembled by Chinese children in labor lessons, has protection against polarity reversal. It is simply implemented using the same diodes: here they are open when connected “correctly”, and when connected “incorrectly” they cut off the load from the on-board network. However, diodes along the power supply circuit are rarely used in powerful current consumers - radios and radios. And they contain elements that are extremely vulnerable to polarity reversal - electrolytic capacitors, installed to smooth out voltage ripples precisely in the power circuits.

Electrolytic capacitors have a high specific capacitance and are therefore popular in electronics. But their weak point is that they work only at a certain polarity of the voltage on the plates; when the polarity is reversed, heating occurs, abundant gas evolution occurs (the capacitor swells), then an explosion. The larger the capacitance and dimensions of the capacitor, the stronger all this is - if a capacitor of a few microfarads clicks slightly, then the “cans” of thousands of microfarads used in amplifiers explode.

Failed capacitors

And a lot of relays in the wiring can make the same sound as the diodes in the alternator bridge. The fact is that in the windings of electromagnetic relays, when the voltage is turned off, a sharp surge of voltage occurs, which has reverse polarity relative to the power source. To eliminate the harmful effects of such pulses on the operation of sensitive electronics, it is customary to use diodes connected in the reverse direction. While voltage from the on-board network is applied to the winding, the diode is locked, and when the winding opens, it opens with an inductive surge pulse and extinguishes it. When the battery polarity is reversed, such diodes will burn out.

Short circuits in the network

What happens if you short the battery terminals? Given the ability of starter batteries to briefly deliver current of hundreds of amperes, an object that shorts the terminals (for example, accidentally caught between the “plus” and the car body) will melt. More massive metal objects can become tightly welded to the terminals or body, causing the battery to go “zero.” At risk are cars where the battery is installed in the trunk - you should not carelessly throw towing eyes there, it is unknown where they will end up under the influence of shaking while driving.

Since such short circuits occur hidden from the owner (a key accidentally dropped during repairs can at least be immediately seen), they are the most dangerous - there is a high probability of ignition in the trunk.

With such short circuits, problems with on-board electronics are possible. The standard ones on German cars are blocked after this, and their functionality is restored only after forced unlocking from a diagnostic scanner.

Cars with CAN wiring are sensitive to power surges. There is a risk of sporadic errors appearing in the controllers' memory.

Incorrect lighting

If the driver mixes up the battery terminals when lighting a cigarette, then the following happens: we get two batteries connected in series, the outputs of which are short-circuited. We get a short circuit already under a voltage of 24 volts. The vast majority of sets of wires sold in stores, whose core cross-section is already insufficient, will instantly burn out, leaving burns on the hands of the unlucky driver. If the wires have a sufficient cross-section, then they will have time to heat up before burning out.

Therefore, always check that the wires are connected correctly. While factory kits at least have color markings, homemade wires are often cut from one piece and do not differ in color. You can mark them with colored electrical tape on the “crocodiles” - this will reduce the risk of incorrect connection.

The “positive” terminals are connected first - first the crocodile is attached to the battery being lit, then to the battery being used. The ground is connected in the opposite direction - first on the cigar battery. Thus, the circuit is closed at the last step on the car being lit.

Since it is equally important to correctly disconnect the battery terminals, the disconnection procedure is also strictly defined. The ground is disconnected first, after which any manipulations with the wires will not pose the risk of a short circuit.

Remember that lighting for on-board electronics is an emergency situation that creates an increased load on the generator and excessive voltage surges in the network of the vehicle being lit during rotation of the starter.