What Size Cable to Reach the Detached Garage | An Expert Guide


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Extending or placing an extra electricity panel for your detached garage is a very used option nowadays and is valid. Normally the detached garage is detached from the house, in electrical structure, and needs this power supply to have an optimal function. Now the question is what size cable to reach the detached garage.

A study found that some people feel more energized when they work on their feet rather than sitting at a desk all day. The researchers discovered this by comparing two groups: one was given aerobic exercise, and the other sat around for an hour with no activity. 

Afterwards, both were asked to do math problems in front of cameras while wearing electrodes connected to computers, counting how much energy was used per second during the task. There was a significant difference between these two measurements! For such reason, we will offer the relevant information that will decipher; what size cable to reach the detached garage.

What Size Cable to Reach the Detached Garage

A 10mm 3core would be sufficient for a wired connection, but if you’re also looking to set up wireless streaming then that’s going to require much more power. The best way of proceeding is by hiring an electrician who can assess the wiring and advise on what needs doing next so it’s not just guesswork!

A 10mm cable will suffice for accessing your Internet through wire-based connections; however, in order to have access from other devices via wireless means (such as smartphones or tablets), which are becoming increasingly popular among today’s population both the home users and business alike) much thicker cables need installing such as Cat5/6 grade cabling.

What Size Cable to Reach the Detached Garage

The cable size will depend on the functions that you will use in the independent garage. Thus, if you want only light or can perform other tasks, such as using an air compressor, drill, among others, it is necessary to calculate the total load. From this question, the size of the cable and the capacity of the distribution board is determined.

For this reason, we will handle common scenarios, based on our location in the United States, using 120-volt wiring. There are three possible approaches to using the correct wiring in the detached garage:

Wiring Issues

  • Extending an established circuit in the detached garage; if you are extending a lighting circuit or standard receptacles or outlets. On the other hand, if it is for standard receptacles and is operated by a 20 amp breaker, you can use 12 gauge wires. Note that if the breaker amperage is different than either of these, you must use the appropriate wire for the size of the breaker.
  • Install a new circuit to the detached garage; it all depends on the size of the breaker, the maximum load, and the type of wire to be used. The standard for a lighting circuit is to have a 15 amp circuit breaker and use size 14 wires, ideal for the required voltage of light bulbs. The standard is a 20 amp circuit breaker and 12 gauge wire to provide power to the outlets.
  • Install a sub panel in the detached garage; use the appropriate wire for the sub-panel breaker, usually 30, 40, or 50 amps. Typically, 30 amps can be size 10, 40 amps can use eight gauges, and 50 amps can use six. These parameters are evaluated when the sub-panel is relatively close to the detached garage.

We will show the distances accordingly for 120-volt circuits with various ampere ratings:

  • 14 AWG 50 ft.
  • 12 AWG 60 ft.
  • 10 AWG 64 ft.
  • 8 AWG 76 ft.
  • 6 AWG 94 ft.

We define AWG as the wire size in U.S. standard and the distance in feet.

Things to Consider when Installing a Sub Panel to a Detached Garage

Installing a Sub Panel to a Detached Garage
  • Find out if there are government regulations in your area that indicate minimum installation requirements, such as how high the sub-panel must be off the ground, type of metal conduit, type of ground rod, and so on.
  • Install approximately 20% above the power you anticipate needing to reduce the possibility of upgrading shortly.
  • Evaluate the complete needs to assess if a complete sub-panel is necessary or an alternative solution such as tandem breakers.

Wiring an unfinished garage

Acquiring an unfinished detached garage, relying on a wiring structure with no idea; the original idea can be frustrating. However, you can look at the other side, use what you own, and turn it into something convenient. In this way; we will offer options to use and shape wiring to meet your needs:

  • Since we have an unfinished garage, the wires will be exposed to plain sight, as they do not have a sheathing.
  • The success in safe, code-compliant exposed wiring is to use the framing members to protect and support them. In this way, no joist spaces are traversed; or studs with wires.
  • The idea is to follow the roof structure; route the cable along with the structure from the switch box to the next box. So, keep all wires attached to the ceiling studs, plates, and joists so they are not subject to abuse.
  • Keep all wires exposed and easy to see, and never run wires on top of walls; keep them on vertical surfaces.
  • Start by planning your wiring layout and nailing down all electrical boxes; run a wire from one box to another. After you have decided on your layout, spend some time carefully distributing the points to give yourself more light and outlets.
  • Remember that depending on the circuit breaker box’s capacity, the cable’s thickness will be the best way to distribute the power.

Size the power cable to my garage.

Defining the dimensions of the feeder cable of the independent garage goes hand in hand with the capacity of the circuit breaker. It will offer; the maximum distance and the size of the cable, guided by the amperages that it supplies. You must consider and define the necessary range of energy; to achieve the use of the implements in your workshop and garage, whether it is lighting or current for electrical appliances. Standard values for circuit breaker voltage on a 120-volt circuit are:

  • 14 AWG wire, maximum distance 50 feet; 15 amp circuit breaker.
  • 12 AWG wire, maximum distance 60 feet; 20 amp circuit breaker.
  • 10 AWG cable, maximum distance 64 feet; 30 amp circuit breaker.
  • 8 AWG cable, maximum distance 76 feet; 40 amp circuit breaker.
  • 6 AWG cable, maximum distance 94 feet; 50 amp circuit breaker.

Size cable to subpanel in a stand-alone building

Sizing a cable to sub panel for a stand-alone building is larger, but it still depends on the circuit breakers. You should use a circuit rated at 240 volts for this type of process because of the range. With this type of circuit, you can use smaller or larger wires to reach longer distances. The circuit breaker can generate a larger voltage, properly distributed to the independent building with the proper tools.

How do I get electricity from my home to my detached garage?

Moving electricity from your home to the detached garage should take into account the distance that separates them. Thus, choose the appropriate circuit breaker amperage to achieve adequate reach and power without loss. The more distance there is, the more amperage capacity the breaker must have; therefore, the size of the cable is bigger. Thus, if the distance between points exceeds 96 feet, you should consider a functional circuit at 240 volts; otherwise, you can work with 120 volts. Read more about Best Garage Door Opener App

How do I put electricity in my garage?

Putting electricity in your garage is a process of adaptation conditioned to the needs you want to cover. We will name the common steps to carry out this task:

  • Regardless of the method to be used, you must be clear about the approximate amount of energy you will need to meet your needs if you are only going to illuminate or need several outlets for electrical appliances. What type of appliances and how much they consume, choose the type of circuit breaker based on their amperages. In this way, we will have the size of the cable to be used to carry out the electrical installation.
  • Then you must mark the electrical points throughout the garage with their proper identification; sockets, switches, and lights. This will reflect the schematic and give you the amount in meters of cable and PVC pipes needed.
  • Install the PVC tubing per electrical point on your schematic, and then run the cable cutting the ends with enough tip to connect to the device. Repeat this operation until the schematic is complete.
  • Install the devices such as sockets, switches, and sockets, joining them with the tips of the cables in their respective space.
  • Finally, make the splices in the electrical junction box to complete the circuit. The neutral, phase and ground connections must be made. The circuit breaker must be ready to provide the necessary energy.

Frequently Asked Questions

What kind of wire do I need for a detached garage?

In general, a 30-amp subset works from 10 gauge wire, a 40-amp wire needs to be 8-gage, and a 50 amp subpanel needs to be 6-gauge. You’ll have a hefty 3- or 4-gage cable that uses 6-gage ground wires if you need a 100-amp subpanel.

What size wire do I need to wire my garage?

Normally you can use 20 amp breakers and 12 gages wires standard receptacles. You should use a suitable wire. Generally of the 30 amps, 40 amplifiers, or 50 amps, if you have the subpanel in your garage for the breaker size of the subpanel.

Can I run a 200 amp service to the garage?

While there is a breaker that is not bigger than 200 amplifiers on your side of the meter, you’re all right.

Does a detached garage need a separate ground rod?

Yeah, to the detached building, you need an electrode (ground rod). It would have given a very excellent grounding electrode to connect to the reinforcement of steel in the slab, but the ship sailed if this is already poured.

What size breaker do I need for a detached garage?

You will utilize the 50 amp breaker between the two structures to manage the load for most garages, using an 8/3 wire.

Is conduit required for garage wiring?

Typically, conduits are necessary when the wire can have potential damage or the weather. Generally, there is no need to fulfil requirements for this kind of cables walls.

Does a garage need a sub-panel?

What power you usually utilize when working in your garage depends on. You will need a 100-amp sub-panel if you are running welders and compressors requiring high power. Only a sub-panel of 50 to 60 amps is necessary if you are undertaking modest work.

What size wire do I need to run a 100 amp sub panel?

The cable has to have a suitable wire gage for ampering the sub-panel – for example. A 100-amp sub-panel will require #4 copper wires or, more generally, #2 aluminium wires.

Are 60 amps enough for a garage?

If you start utilizing a huge soldered, larger pump, or electrical heat, you’re not going to go big and have high-demand items. Sixty amplifiers will do you great things.

Does a detached garage need a main breaker?

Not at all! A separate structure fed by another building would require detaching the drivers to enter the building next.

What size cable should I run to my garage?

If all that you need is, 1.5mm2 should be OK. However, 2.5mm2 should also be safe. You must measure the distance from the supply to the garage. Even 2:5 mm2 would push for a 30-meter run.

What size wire do I need to run a 100-amp subpanel?

For example, #4 copper wires or #2 aluminium wires, more frequently. (Aluminum is frequently utilized for feeder wires since the costs of copper wires are generally significantly cheaper.)

Does a detached garage need a ground rod?

Yes! 6 AWG solid for a grounding electrode connection is the standard minimum size.

What size Armored cable do I need for a shed?

Between the home and shed, you can find 2.5mm of 3 core SWA underground. However, from the house to the shed are transmitted 20 amps RCD.

Will 1 0 aluminum wire fit in a 100 amp breaker?

No, Al #1/0 in-house service is good for a maximum of 125A; if the distance is much than 100′ or so, it may be 100A.

Can you run a 100 amp sub panel off a 100 amp main panel?

You can operate a 100 amp substratum from a 100 amp main panel, as the total amperage of the box can be double, indicating that you can run a subpanel of up to 200 amps.

Can I run a 100 amp sub panel off 200 amps main?

The ideal way to use a panel with the main breaker and main lugs is to take 200 amps from a 200 amp panel.

Bottom Line

We then have all the pertinent information needed to decipher what cable should run to the detached garage. Correctly using this material will allow you to find the right size; to supply electricity to your detached garage. In this way, elaborate your scheme adapted to the needs and uses of your independent garage. Intending to use the necessary energy resources to use electrical appliances, air compressor, a power outlet, and have the necessary lighting.

We recommend professional advice or electrical inspector; count on the help of people with experience in electricity, an electrician will help you do a proper job. You must know the area to try to make any electrical installation if it is the case. It is delicate and unsafe to perform any electrical operation without prior knowledge or experience. There is no need to risk your electrical equipment and endanger your integrity.

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