What size fuse should you use with 8 guage wire

This is an in-depth fuse tutorial explaining everything you need to know about fuses and how to size a fuse. For your fuse to do its job correctly and protect your wires, it should be rated about 1.

Actually, the load of the circuit should have nothing to do with choosing a fuse size. So you just bought your stuff at Oznium and are getting ready to plan your installation while USPS gets it to your door. One of the first questions to ask when planning your installation is what size wire to use, which will later determine what fuse to use. Current is measured in Amperes, abbreviated to Amps or just the letter A. Add the values and divide by to get your total current in Amps.

You can use this value in the fuse size chart above to determine the minimum wire size required. Put 1. That table tells you that you should have no smaller than 21 gauge wire for your circuit. Fuse rating is the amount of current needed for the fuse to blow or break. When this happens, it stops the electrical power from flowing through the electrical circuit. The fuse rating is a valuable piece of information because it helps you to protect your electrical circuit and therefore should never be neglected.

Every electrical circuit will need a different amount of electrical current, what is just right for one electrical circuit may be too much or too little for another. Do the right thing and protect your circuit. Hopefully this guide helps you to install all the products here at Oznium quickly and most importantly, safely. Anyone who needs additional information or has specific or more complex installations, feel free to get in touch or post a question below.

what size fuse should you use with 8 guage wire

I have a question what size fuse in my car car should I run with a W LED high beam and low beam Just want to know what size I should be running to get the most out of my LED headlights whatever information you can give me that would be helpful thank you. Or If there is some pre installed factory wire and you have changed the lights. If the wire shorts out and has too large a fuse installed it could melt the insulation right off the copper conductor and get so hot that it could start something on fire!

If I misunderstood what you were asking I apologize. That is only one part of the considerations of properly fuse protecting a circuit. I am installing a 20 amp max marine waterproof 12VDC socket above my rear bumper for accessories such as a tire inflator 15 amps. The cable run from the battery is approximately 15 feet. I want to ensure no power loss to plan on running a 10AWG wire.

Is that too much, too low, or about right? MIght install separate fuse box in the engine bay, so can add more accessories later.

My question is How we check fuse rating ok, Like if our fuse is 40A and on the fuse have written 40A by manufacturer but how we check it is 40A I think may be that fuse 50 and 30 A so plese provide answer. To check whether a fuse blows at a certain current, you need to run different currents through it until it blows.

I have a similar situation as a previous poster.

what size fuse should you use with 8 guage wire

I want to install an additional 12VDC 15A outlet in my car. Anyway, the pigtail with crimp is usually a 16AWG wire.Usually there are two kinds of battery cables people use often for high wattage power inverters in the market. Standard Cables :.

Use for inverters with DC input terminals that have threaded posts. PS Cables: These cables have ring terminals on the battery end, and stud terminals on the inverter end. Use for inverters with DC input terminals that have a tubular hole with a set screw. Most of Pooxtra Inverter's cables sets are Standard Cables which are constructed from high quality welding cable and feature heavy duty terminals, dual wall heat shrink, and high temperature terminal protectors.

We can make custom length cables for your application. If our cable size coming with inside package is not what you need, please call or send email to support pooxtra-inverter. Choosing the right wire size for your inverter DC battery is important, since a wire that is too small can overheat and possibly start a fire. The American Boat and Yacht Council ABYC publishes charts with valuable detail to help experienced boat builders and installers determine what wire size they need.

Although these charts are an excellent resource, they are a bit intimidating. We distill the information on these charts to a more manageable size for installers and boat owners alike. Quality marine wire, as specified by ABYC standards, will always be stranded rather than solid, and always tin-plated copper. A lower rating will decrease the current-carrying capacity of the wire.

Most electrical products include a rating label, or you can find the amperage rating in the documentation that came with the product. Note that the total length of the circuit is the round trip distance from power source usually the battery to the product and back.

What size guage power wire and fuses should be used in a mobile install?

Allowable voltage drop is based on whether a circuit is critical or non-critical. If you have specific questions about your installation please consult an ABYC certified installer. The cable size depends on the distance between battery and inverter, when connecting the inverter to the battery always use an overcurrent protection device, such as a fuse or circuit breaker, and use the thickest wire available, in the shortest length practical.

Cable size recommendations may vary among inverter brands and models; check the Owner's Manual for the model you purchase before you buy the wire for it.

But the cable we provide is durable and practical. Cart 0.Growing up in a family surrounded by electricians, we were always discussing codes and theory around the house. Much of what I know came second-hand through my dad but also through Mike Holt, a well-known electrical author and instructor I now have the privilege of calling a friend. Over and over again, I have heard HVACR technicians and electricians quote rules of thumb regarding wiring sizing, and I have witnessed and participated in many heated debates on the topic.

During service calls, being able to identify undersized conductors can help resolve compressor start issues or intermittent trips of breakers or fuses.

what size fuse should you use with 8 guage wire

Knowing appropriate and inappropriate breaker and conductor sizes will save you and your customers time and money. I am certainly not suggesting HVACR techs engage in performing work outside of their skills or licensures, but, in many cases, being able to identify the problem and making the repair are two different things. Here are some additional factors to be considered:.

Aluminum wire has a lower ampacity than the same gauge copper wire, meaning aluminum must be larger to accomplish the same ampacity job as copper wire.

These ratings on the data tag tell us exactly what minimum ampacity the circuit must be capable of carrying as well as the maximum size the circuit breaker or fuse may be able to protect the circuit against in an overcurrent condition. Take a look at the Lennox air conditioning condensing unit tag on Page Notice that the MCA is This means it is allowable to install this unit on a circuit breaker rated at 50 amps and a conductor rated at I know this goes against what many of you have been told and understood your entire career, but take a deep breath and read on.

NEC article was added because air conditioning and refrigeration systems are different from typical loads, like lights and heaters. Air conditioner compressor and fan motors are largely inductive magnetic loads and have different characteristics than purely resistive circuits. Article has specific guidelines for HVAC and refrigeration equipment manufacturers to follow when writing the equipment data tags as well as for electricians when sizing conductors. There is a lot there, but here are two highlights that directly apply to you as an HVACR professional.

If you hesitate at the thought of doing this math for every system you work on, the NEC Article In these overload conditions, the overload protections on the motors themselves are designed to protect the circuit. If the overload protection on the compressor or fan motor fails, the windings in the motors have a far lower ampacity than the branch circuit and will fail open or shorted before the branch conductor will fail. In the case of any significant ground-fault short, the overcurrent protector breaker or fuse will still protect the circuit.

In some cases, contractors have stated that certain municipalities are requiring that conductors be sized based on the breaker size instead of the MCA. This is not uncommon, but it is usually a matter of a respectful conversation about the above NEC articles. While certain local legislation may supersede the NEC with additional regulations, the NEC is a nationally recognized standard throughout the U.

It is rare that a building department will ignore entire articles of the NEC when it is brought to their attention in a respectful manner. When this is done, the conductor will be properly sized according to the NEC. While no standard is perfect, I have found that knowing the NEC and looking carefully at manufacturer listings and labels can save you time, your customers money, and help keep everyone safe.

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what size fuse should you use with 8 guage wire

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September 18, Report Abusive Comment Thank you for helping us to improve our forums.Behind these gold-colored switch panels lurked a year-old tangle of do-it-yourself wiring projects.

The amazing thing is that all of the systems still worked. Does your boat have a similar legacy of bad electrical work? Safety onboard begins with a reliable DC electrical system, properly installed with quality wiring, connections and components. This is critically important because, according to BoatUS Marine Insuranceproblems with DC electrical systems are responsible for 32 percent of onboard fires, more than any other category of causes.

In my several decades of owning and working on boats, I have personally seen more examples of scary do-it-yourself DC electrical projects than any other type of boat equipment disaster. Something about volt DC power seduces and encourages hack electricians to try their hand using household-grade wire and terminals.

This stuff really is not rocket science. This West Advisor will help you understand some basic standards and practices of DC marine wiring. Even if tinned copper, your wiring should not be run in bilge spaces or other areas subject to moisture from spray or dripping.

If conductors must be routed in the bilge or other areas where water may accumulate, the connections shall be watertight They should not be used in applications where subjected to vibration or frequent flexing and must never be used for volt applications. For safety, use only wire that is marked with size and type.

In general, wiring on boats should be of the stranded type, not solid copper wire used in household applications, which does not withstand the vibration found onboard a boat. Select wire color from the list below. This is a basic question you need to tackle when designing your own wiring. Installing overly large wire is expensive and adds weight, but installing wire of inadequate size is a safety concern.

There are four key variables you should consider: amperage or ampacity, temperature, whether the wires are bundled closely together, and voltage drop. Ampacity is defined as the current carrying capacity of a conductor or device—how many amperes of current you can run through it. Many electrical loads, such as LED lights, for example, draw a constant amount of amps so are simple to calculate by checking the specs of the device.

Others, such as power inverters or any device operating an electrical motor, will have a large spike in amperage when they start operating.When selecting the correct size of a battery cable to power your electrical system or project, a few factors need to be considered. You should know what is the maximum amount of current your system will need, how long the cables need to be, and the cost of larger cables versus smaller cables.

When figuring out the length you need, you will add together the lengths of both the positive and negative cables to get your total length. First let's talk about the importance of current when selecting your battery cable. Current is measured in units called amps. Each of your electrical devices will require a specific number of amps to operate.

Add up the current requirements of all your devices and this will be your maximum amperage needed. Sometimes, devices might be rated in watts instead of amps. In this case, simply divide the number for watts by your system's voltage to get the amperage requirements.

The second thing to consider when selecting the correct size battery cable is the length of cable you need. The length is important because as electricity flows through a battery cable, there is an resistance to the flow of that electricity which will generate heat in your battery cable and manifest itself in the form of what is called a voltage drop at the end of the cable.

Voltage drop is simply the voltage seen at one end of the cable minus the voltage seen at the other end of the cable. This voltage drop is influenced by the diameter of the copper conductors inside the cable, or the gauge size, and the total length of the cable - The longer the battery cable is, the higher the voltage drop will be, and the larger the diameter, or gauge AWG of the battery cable, the less the voltage drop will be.

Why is voltage drop important? At the source, or battery, you will read 12 volts using a voltage meter, but at the other end of the cable your voltmeter will only read If your circuit needs amps of current, the battery cable will be absorbing 2 amps 24 watts of current because of it's resistance, leaving 98 amps available.

Now your voltmeter at the other end of your battery cable will read Your cable will definitely get warm to the touch. This amount of voltage drop may begin to cause other devices to not work properly - light bulbs will be dimmer, fans and motors will be weaker, and if the voltage drop is high enough computer systems can fail, and even the cable itself can be destroyed leading to a catastrophic failure and even an electrical fire!

In summary, when selecting the correct size of battery cable, you need to take into account the total maximum amperage your electrical system requires, the voltage of your system usually 12 voltsthe total length that your cables need to be, and the amount of voltage drop you are willing to accept versus the amount you want to spend. Also, be aware of imported cable versus American made cable. Many imported brands are sized in millimeters instead of the gauge scale used in the USA.

Imported cable will often be smaller in diameter than American made cable, but be sold as it's gauge counterpart.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.

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.

The proper circuit size, as indicated by amperage, is determined by several factors, including the planned load on the circuit, the number of outlets or light fixtures, and the length of the circuit. 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.

If you've shopped for electrical wire, you have likely noticed that there are many types and sizes of wire to choose from. 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.

Common sizes include,8- 6- and 2-gauge wire. The size of the wire dictates how much current can safely pass through the wire. 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.

For example, there is aluminum wiring in some homes, and aluminum wires have their own ampacity-carrying capacity. 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.

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. But an evaluation and replacement with copper wiring may be a good idea. One more thing to keep in mind is to select the style of wire that best fits your needs.

Some wire is stranded, while other wire consists of a solid copper conductor. In installations using metal conduit, the solid wire doesn't always pull as easily if the conduit has a large number of bends. But solid wire is usually easier to secure under screw terminals, such as those found on standard switches and receptacles. In standard usage, though, the wire conductors in conduit or NM cable for household wiring will beor gauge wire that is a solid copper conductor.

Both these devices are designed to sense current overloads and to trip or "blow" before the wires can overheat to the danger point. 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. 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.

For example, plugging a heater rated for 20 amps into a amp circuit wired with gauge wire poses a distinct danger. 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.

The circuit will draw the power asked for by whatever is plugged into them and no more. So, for example, running a laptop computer with a very small amperage demand on a amp circuit wired with gauge wire is perfectly fine.

What I had to teach myself: types and sizes of electrical cable

The potential for danger is most pronounced with the use of light household extension cords. Many a household fire has occurred when a light extension cord with gauge wire is used to power a heater or heating appliance of some sort.

Most manufacturers will discourage the use of any extension cords with portable heaters, but if one must be used, it has to be a heavy-duty cord with a high amperage rating that matches the amperage of the appliance and of the circuit it is plugged into.

Amperage Capacities for Standard Non-Metallic NM Cable gauge wire 15 amps gauge wire 20 amps gauge wire 30 amps 8-gauge wire 40 amps 6-gauge wire 55 amps 4-gauge wire 70 amps 3-gauge wire 85 amps 2-gauge wire 95 amps.

Wire Use Rated Ampacity Wire Gauge Low-voltage lighting and lamp cords 10 amps gauge Extension cords light-duty 13 amps gauge Light fixtures, lamps, lighting circuits 15 amps gauge Kitchen, bathroom, and outdoor receptacles outlets ; volt air conditioners 20 amps gauge Electric clothes dryers, volt window air conditioners, electric water heaters 30 amps gauge Cooktops and ranges amps 6-gauge Electric furnaces, large electric heaters 60 amps 4-gauge. Related Topics.Choosing the right wire size for your DC electrical project is important, since a wire that is too small can overheat and possibly start a fire.

The American Boat and Yacht Council ABYC publishes charts with valuable detail to help experienced boatbuilders and installers determine what wire size they need.

Although these charts are an excellent resource, they are a bit intimidating. This technical brief distills the information on these charts to a more manageable size for installers and boatowners alike.

Alternator Wire Gauge Chart

Quality marine wire, as specified by ABYC standards, will always be stranded rather than solid, and always tin-plated copper. A lower rating will decrease the current-carrying capacity of the wire. Most electrical products include a rating label, or you can find the amperage rating in the documentation that came with the product. Note that the total length of the circuit is the roundtrip distance from power source usually the battery to the product and back.

Allowable voltage drop is based on whether a circuit is critical or non-critical. Although this process uses information from ABYC E to recommend wire size and circuit protection, it may not cover all of the unique characteristics that may exist on a boat.

If you have specific questions about your installation please consult an ABYC certified installer. The Circuit Wizard, at circuitwizard. It allows you to input detailed information including wire insulation temperature rating and other derating factors.

The Circuit Wizard is easy to use, and is accessible from any computer with an Internet connection. Look for additional articles on the topic of selecting circuit protection at bluesea. Found this article helpful? Get the latest when you sign up for our newsletter!

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