Incorrect polarity connection that has caused LED failure will typically result in no light emission and open-circuit LEDs.
LEDs, being diodes, will only allow current to flow in one direction. And when there's no current-flow, there's no light. Luckily, this also means that you can't break an LED by plugging it in backwards. Rather, it just won't work.
The wires connected to the LED lights need to be plugged into a power source correctly in order for the light to turn on. Generally, red wires indicate a positive connection and black wires indicate a negative connection.
LED lights require a certain voltage, such as 24 or 12V. When they run at higher voltages, they become extremely hot. Extreme heat damages the LED lights or the soldering around them. Due to the heat damage LED lights start to dim, flicker, or may die entirely.
LED polarity
This means that LEDs (and other diodes) have positive (+) and negative (-) sides to them. For an LED to work it needs to be connected to a voltage source with the correct side. The voltage supply side of the diode is the positive (+) side, this is called the anode. The negative side is called the cathode.
By nature, LED lights are polarity-sensitive. If the voltage is of the wrong polarity, it is said to be reverse-biased. Very little current will flow, and the device will not light up.
So anything from about 4.5 to 5.5 Volts is safe for these LEDs and 6V is the 'rated absolute maximum'. Any higher and they'll burn out quickly.
You have a 12 V supply and each LED might need up to 3.5 V. (12 V)/(3.5 V) = 3.4 LEDs max. Since you can only have whole LEDs, the answer is 3.
Increasing heat from power dissipation causes a failure of the LED die. The change in colour, e.g. red and green LEDs going yellow at high currents, is probably because the die is actually glowing hot, i.e. near failure.
A.K.A. as long as you're feeding it DC power your lights will work just fine, grounded or not. The only way a cheater plug or an ungrounded connection will affect your lights is if a power surge blows your lights out!
The colors of the wires are red, black, and white. Red becomes the first positive with black the second positive. The white light becomes ground. The 3 wire light can best be installed as a blinker and brake.
If the LED has two leads with leads that are equal in length, you can look at the metal plate inside the LED. The smaller plate indicates the positive (anode) lead; the larger plate belongs to the negative (cathode) lead.
There would be a shock hazard, and some devices might not work correctly. Depending on where exactly the wires are flipped, ground fault detecting circuit breakers may become ineffective. All around, this is a bad idea. Save this answer.
With reverse polarity, the hot wire feeds electricity into the socket and you'll get zapped if you touch it. Inexpensive circuit analyzers will let you know whether an outlet is wired correctly.
Nothing will break. It is like shorting the pins of the LED together. In that case, there is no voltage across it, so it can not be damages.
Quite intuitively, providing more than 12V DC on a 12V LED strip is not a good idea, because you may cause the LED strip to be over-driven, burning out the diodes or causing excessive heat buildup that can damage both the circuit and on-board components.
Is one better than the other… Series, Parallel, or Series/Parallel? The requirements of a lighting application often dictate what type of circuit can be used, but if given the choice, the most efficient way to run high power LEDs is using a series circuit with a constant current LED driver.
You cannot run 240v lights on 12v. You can, however, run 12v lights on 12v. The aim seems to be to run safe voltages into your garden. You can connect some of these in series to raise the voltage, but I would strongly recommend not exceeding 3 in series, for 36v supply.
LED lights are unlikely to start a fire. The bulbs don't get hot enough to ignite anything. The biggest risks are faulty wiring or overloaded circuits. This is often caused by the way they are installed, rather than an issue with the light itself.
Yes, 12V can certainly cause sparks if there is a connection that is opening and/or closing.
Voltage that is too high can cause premature failure of electrical and electronic components (e.g. circuit boards) due to overheating. The damage caused by overheating is cumulative and irreversible.
Sometimes it's easiest to just use a multimeter to test for polarity. Turn the multimeter to the diode setting (usually indicated by a diode symbol), and touch each probe to one of the LED terminals. If the LED lights up, the positive probe is touching the anode, and the negative probe is touching the cathode.
You can try to find the longer leg, which should indicate the positive, anode pin. Or, if someone's trimmed the legs, try finding the flat edge on the LED's outer casing. The pin nearest the flat edge will be the negative, cathode pin. There might be other indicators as well.
The longer lead is the Anode and will always be connected to the positive side of your circuit. The shorter lead is known as the Cathode and will always go to the ground / negative side of your circuit.