How does bad wiring cause fire?

There are several ways a fire can start. A loose connection under heavy load can raise resistance, which has the effect of raising the voltage beyond the rating of the wire. Even 4 prong plugs can catch fire because of this. Shorts can also catch fire. Many causes here, but a short is like arc welding and it can be very hot.
Too much load on the circuit can also be a problem, where somebody puts in a circuit breaker rated to more amps than the wire gauge amp rating. Most home wiring is 14 gauge, rated to 15 amps. Some people get tired of tripping the breaker and put in a 20 amp (or larger) breaker. The wire is being asked to carry more power (watts) than it should, which can cause the wire to heat up. If the overload is bad enough, the heat will catch the insulation on fire.
Poor grounding tends to be less of a direct fire issue than a real safety problem. Poor or no grounding can kill by electrocution in cases where your body becomes the best path back to the box or earth. Some people strip a conductor and wrap another wire around it to make a connection. This is just inviting an electrical fire. Connections of wires should be made with wire nuts and twisted together. Loose connections on switches and outlets pose another problem.
When tightening a wire around a terminal screw on a device, bend the stripped wire in a half-moon shape and put the open end towards the right. Tighten the screw in a clockwise motion until tight. This will draw the copper around the screw, thus closing the loop tighter. If you have the open end the other way, the half moon will actually open up a bit, causing the connection to not be as secure. These are all things to avoid with your wiring. Be careful when installing anything to avoid a fire.www.electricalservicesfl.com

Choosing Aluminum or Copper Wiring.

The biggest difference between the two metals is that copper is just a lot more stable metal than aluminum. And the worst problem for electricity is heat. It’s important to have a stable metal when it gets hot. Aluminum is fine, but it’s not as good as copper over time because the instability of that metal, when it heats up it contracts and expands. As it cools down, it contracts and heats, it expands. This is usually called, “cold creep”. The tightness of the wiring decreases with each progressive warm-cool cycle experienced.

With that happening over years and decades especially at your main service, wall plugs, or something that causes a loose connection and it starts arcing. That arc can then create a fire over time. This doesn’t occur with copper if it’s installed properly and it’s tight at the beginning when it’s installed. The other problem with aluminum is oxidation. Both metals are exposed to air and copper oxidizes, as you can see when it turns green, but it doesn’t affect the connection of the wire. When aluminum oxidizes, it creates this crust that builds on it, this crust can sometimes get as much as a quarter inch thick. Including the fact that the metal is not as compatible to the heat and temperature problem. With that crust building up, it will also create a gap between the connections that can cause arcing.

So copper is always better than aluminum and everything except price. And the main reason that it’s being used is because it’s so much cheaper. When it comes to costs, aluminum is more affordable than copper wire. With aluminum, you require just about half of what would be required if copper wire were to be used. Where extensive wiring is to be undertaken in a home, the difference between the two materials can give you significant savings. Also aluminum is lightweight and easy to work with. It is also a flexible material which increases job efficiency. Because of how light aluminum is, it becomes helpful when wiring needs be done over long distances. The use of lighter materials over long distances makes the job less rigorous. Aluminum also reduces corona, an electric discharge associated with high power transmissions. 

Copper on the other hand has one of the highest electrical conductivity rates amongst metals. This makes it easier soldered with. It also makes it possible for smaller conductors to be used to transmit power loads. Smaller conductors are easier to transport and install. They also cost less which helps manage wiring costs. Due to its high ductile properties, copper can be formed into very fine wire. This adds to the versatility of copper wire. Copper has a high tensile strength. It can undergo extreme stress but show minimal signs of wear and tear. This makes the wiring more durable than aluminum. Due to its great resilience, high durability, low maintenance and high performance, copper wiring also adds to home value.

The obvious choice when choosing a metal to wire your house with or any electric job would be copper. Even if the cost is higher, it’s worth it in the long run.

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