# amperage vs current

While circuit breakers or fuses offers good protection against overloading wires and overheating them, they are not absolute protection. The size of the wire dictates how much current can safely pass through the wire. Common sizes include 14-, 12-, 10-, 8-, 6-, and 2-gauge wire. The higher the amperage rating of the circuit, the larger the wires need to be in order to avoid excess heat that can melt wires and cause fires. There is a big difference between the two though as watts is a comprehensive measurement of power while amps is just the quantity of current … In other words, an enough power is required to pass in the human body for proper electric shock. Current will kill you but some amount of voltage is required to flow that current in the body breaking the human body resistance. Whenever a circuit is extended or rewired, or when any new circuit is installed, it is critical that the new wiring is made with wire conductors that are properly sized for the amperage rating of the circuit. I (A) = P (W) / V (V). Electrical current is measured in amps. So, for example, running a laptop computer with a very small amperage demand on a 20-amp circuit wired with 12-gauge wire is perfectly fine. Both these devices are designed to sense current overloads and to trip or "blow" before the wires can overheat to the danger point. Some wire is stranded, while other wire consists of a solid copper conductor. The current I in amps (A) is equal to the power P in watts (W), divided by the voltage V in volts (V):. The number of devices connected to the circuit usually determines how much current will flow through the wire. There is the potential for danger anytime a device or appliance tries to draw more power on a circuit than the wire gauge is rated for. 115 volts motor - single-phase : 14 amps/hp; 230 volts motor - single-phase : 7 amps/hp; 230 volts motor - 3-phase : 2.5 amps/hp; 460 volts motor - 3-phase : 1.25 amps/hp; Always check nameplate information before designing protective devices, wiring and switch gear. Every now and then one of our electric-related articles will surface an old debate: what's really dangerous: voltage or amperage? For standard non-metallic (NM) cable, these amperage capacities are: These ratings are for standard copper NM sheathed cable, but there are instances where these amperage ratings vary. Amps vs Watts. The potential for danger is most pronounced with the use of light household extension cords. On the other hand, there is no danger whatsoever by plugging appliances with mild electrical loads into circuits with heavier gauge wires and a higher amperage rating. One more thing to keep in mind is to select the style of wire that best fits your needs. Timothy Thiele is an electrician who advises residential DIYers on how to make home installation projects safe and easy. Electrical current is measured in ampacity, and each wire gauge has a maximum safe carrying capacity. For example, there is aluminum wiring in some homes, and aluminum wires have their own ampacity-carrying capacity. If you've shopped for electrical wire, you have likely noticed that there are many types and sizes of wire to choose from. I (A) = P (W) / (PF × V (V)). So the main cause is the voltage and current as an effect is the killer at specific rate for specified period. In standard usage, though, the wire conductors in conduit or NM cable for household wiring will be 14-, 12- or 10-gauge wire that is a solid copper conductor. Each wire size, or wire gauge (AWG), has a maximum current limit that a wire can handle before damage occurs. But they are not foolproof, and it is still important to guard against exceeding the amperage rating of any given circuit by plugging too many appliances into them. In installations using metal conduit, the solid wire doesn't always pull as easily if the conduit has a large number of bends. Once the proper amperage is determined, though, it is critical, that the wire gauge used in the circuit is appropriate for the amperage of the circuit breaker. Wire is sized by the American Wire Gauge (AWG) system. DC watts to amps calculation. It is important to pick the correct size of wire so that the wire doesn't overheat. The most recent post that raised the issue was last week's Frigidaire wall oven heating issue where I warned readers to turn off the breaker because '220 volts can be lethal.' Should the circuit breaker fail to operate correctly, that heater will draw more current than the wires can safely handle, and could heat the wires to the point of melting the insulation around the wires and igniting surrounding materials. Different types of wire are intended for different uses, but with any of these wire types, knowing the right wire size, or gauge, is key to making the right choice. That is not to say you are necessarily at risk just because you have aluminum wiring, because those connections may work forever if not overloaded. Many a household fire has occurred when a light extension cord with 16-gauge wire is used to power a heater or heating appliance of some sort. For example, plugging a heater rated for 20 amps into a 15-amp circuit wired with 14-gauge wire poses a distinct danger. The circuit will draw the power asked for by whatever is plugged into them and no more. https://learn.sparkfun.com/tutorials/voltage-current-resistance-and-ohms-law Introducing "One Thing": A New Video Series, The Spruce Gardening & Plant Care Review Board, The Spruce Renovations and Repair Review Board, Kitchen, bathroom, and outdoor receptacles (outlets); 120-volt air conditioners, Electric clothes dryers, 240-volt window air conditioners, electric water heaters, Electric furnaces, large electric heaters. Aluminum wiring was once widely used, but because it was found that aluminum had a greater expansion profile under load, it often loosened wire connections and sometimes caused electrical fires.