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Answer: If the spark comes from a hole or crack in the insulation on the cord, it means the wire inside is exposed. That can be extremely dangerous. Stay away and ask an adult to disconnect the cord at once, and have it repaired or replaced.

Answer: The toroidal coil magnet in in Geneva, Switzerland generates 4 teslas, which is about 100,000 times as powerful as the Earth’s magnetic field.

Answer: First of all, we would have to assume that the wire formed part of a circuit. If there’s no circuit then a current is not present. A magnet can only induce a current in a wire if the wire is between the magnet’s two poles. The wire and the magnet must be moving relative to each other.

Answer: As you’ll see in the Electricity and Water section of this site, water is a good conductor of electricity, and this is why it is dangerous to mix the two. If your body comes in contact with water and electricity at the same time, the water will help conduct the electricity through you to get to the ground. This means you would get an electric shock, which could possibly be severe! Therefore, using any plugged-in appliances around water (such as blow-dryers, radios, and shavers) increases your risk of electric shock. So does shooting high-power water squirters at power lines. Check out our section on water and electricity at

Answer: A technician will use what’s called a solar inverter. This type of inverter removes the electrical power, either from your solar panels or batteries, and turns it into AC power, that is ready and usable for your household appliances.

Answer: If you are ready to go 100% solar, then disconnecting from your utility is the easy part! You’d just tell them you’re closing your account, and a technician would come out and take care of it.

Answer: First, you’d need to make sure you could maintain an adequate supply of electricity when the sun isn’t shining (like at night). For that, you’d need either an array of large batteries that can store enough energy to keep your house powered 24/7, or a diesel generator, or both. (If you use a generator, it needs to be properly housed and vented according to local and state regulations. There might also be regulations about using big batteries, too.)

Answer: The first thing to know is that a non-contact “voltage tester” isn’t a voltage meter—it’s a voltage detector. It works by telling you if there is electrical potential in a wire (or a metal object in contact with a wire). It does that by detecting the electromagnetic field around the charged wire or object. To measure the voltage in a wire, you need a voltage meter, which becomes part of the circuit when its two contacts are applied to the wire.

Answer: The physical size of the main switch on an electrical panel varies by the switch manufacturer. It also depends on the type, size, and age of the panel and the building it serves. For instance, some older panels don’t have a main switch.

Did you know that the size of a main switch can also determine the amount of electricity that is controlled? While this can vary, the main switch for a large office building controls a much greater amount than a switch for a small studio apartment. The code standard for a main switch that serves a 3-bedroom, 2-bath home is 200 amperes (amps).

Answer: When the lamp breaks, its power cord or the cord's connection to the lamp could become damaged. A damaged cord or connection can allow water to easily reach the electricity that runs through the lamp. Electricity flows easily through water, so if you were to touch the wet cord--or even the puddle around it--you could suffer a serious electrical shock. Always keep water away from electrical appliances, whether they are broken or not!

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