What SIze Of Transformer Do You Need For Landscape Lighting.

If you need to tap electricity from a power source for your outside lights, you will need to run it through an outdoor landscape lighting transformer.

The question most people running outdoor garden lights do not care to answer first is what size of a transformer is needed and how much power each type of light to be installed in the garden needs? This post will answer those questions and more.

Landscape lighting transformers are available in 3 types:

1) 120 volt to 12-volt Landscape lighting transformers.

This landscape lighting transformer is the most common type and is able to power up to 12 lights. The wattage of these lights can vary from 50 watts up to 400 watts.

If you plan on adding more than 12-15 lights, we recommend that you purchase a 240-volt landscape lighting transformer so you can spread out your wattage load between two 120 volt transformers (see instructions directly below).

2) 240 volt to 12-volt Landscape lighting transformers.

If you plan on adding more than 15 lights, we recommend that you purchase a second 120 volt landscape lighting transformer and connect them together using this connector.

Then feed both of your 120 volt landscape lighting wiring from one spot. This is a very common installation.

3) 240 volt to 120-volt Landscape lighting transformers.

This landscape lighting transformer is a lot less common and provides a 24-volt current that powers your lights directly off of a 24 volt(+) power source. This typically powers low-wattage 60-watt lights or LED light strings.

This is also another transformer that is very popular is a 120/240-volt with a 5 amps rating. It can power up to 12 low voltage light fixtures with a maximum of 2,000 watts at a time or 10 low voltage lights with a maximum of 1,600 watts at a time for 120-volt lighting fixtures.

4) step down transformer.

The latter two allow you to power your landscape lighting using standard household voltage (120 volts). You can use these transformers to operate your outdoor lighting fixtures that are made up of low voltage (12 volts) lights.

One very important thing to remember is you cannot mix 120-volt and 12-volt lighting fixtures on the same circuit.

Here are some tips to consider when looking for a transformer:

1) How many watts does it take to power the outdoor lighting fixtures that I have?

The wattage of the lights you plan to use outdoors play a big role in choosing a transformer. For example, if you plan to use 200 watt lights and your transformer is only rated for 150 watts max, you will not be able to use all of the lights at the same time. Make sure to look at the light manufacturer’s specifications on the box or ask your supplier about how many watts can you run at the same time with a transformer.

If you plan to use more than one type of lighting fixtures, i.e., low voltage and 120-volt lights on the same circuit/transformer, One of One Touch Landscape Lighting’s step down transformers is recommended because it can power both types of light fixtures at the same time

2) What are the voltage, wattage and amperage of my lights?

Both wattage and amperage of your lights are very important when choosing a transformer. The voltage rating of the transformer should match the voltage rating of your lights.

The wattage of light is how much energy they consume and amperage is how much electric current they need to work properly. You may want to know this for planning purposes or you can ask a Landscape Lighting’s sales representative about this information.

3) What size of transformer do I need for my landscape lighting project?

One of the popular and widely used Landscape step-down transformers is favored the most as it can power both types of light fixtures at the same time, even though they use different voltages. This is because it has a built-in switch that allows you to set it to the voltage your lights require.

3) What is the total length of wire needed for all lights on a circuit?

The total length of your wire needed for your lights to the circuit is one of the most important factors when choosing a transformer.

The longer your wiring runs, the higher voltage it loses over distance. To compensate for this loss, you need to choose a transformer with a slightly higher wattage rating than what is required by your lights.

This will give you enough wiggle room so that the lights don’t dim every time they reach a long distance.

Getting one of the popular Landscape Lighting’s step-down transformers is recommended as it can power both types of light fixtures at the same time.

The switch inside the transformer allows you to choose 120 voltage or 12 volts for your lighting fixtures, making this transformer one of the most versatile choices available.

4) Do I want one or more transformers on each circuit so I can add additional light?

Additional lighting after each circuit will require more wattage.

If you want to power multiple fixtures on the same circuit at once, you will need more watts than if each light is powered individually (one by one). If this is your plan, you will also need to choose a transformer with a higher wattage rating than your original requirements. Another option would be purchasing another transformer for each circuit.

If you have a large landscape lighting project, it would be ideal to talk with Landscape Lighting’s Technical Sales Representative who specializes in helping its customers properly size and power their landscape projects.

They can help you determine the most cost-effective way to light your entire landscaping project after carefully looking at your requirements, design and budget.

If you are using LED light bulbs, then it is recommended that you use an outdoor-rated GFCI outlet with a built-in timer and ground fault interrupter (GFI) protection; if not, make sure the circuit breaker in the panel box where any new wiring is installed has been upgraded to 120 volts.

You can also install a dedicated line from the electrical service panel or individual meter to serve only as an outdoor lighting receptacle.

The most common types of transformers used in commercial landscapes are:

  • 1) 50 amp – This is the most common size that one would need for landscape lighting. If you are using 50 watt light bulbs, you will need a 50 amp transformer.
  • 2) 80 amp – These are typically used in commercial applications with larger wattage lights or large areas of coverage.
  • 3). 100 amp – Usually are needed for large commercial landscapes. This is used in applications with higher wattage lights, LED lights, or larger areas of coverage.
  • 4) 120 amp – Usually are needed for very large commercial landscapes that have many fixtures or are used to power stringers that feature multiple sets of light bulbs, etc.

The above recommendations are general guidelines and it may be necessary to go up or down in transformer size, depending on the wattage of the lights and their distance from the transformer. Be sure to check with an electrician before making any purchases.

50 Amp Landscape Lighting Transformer

The 50 Amp landscape lighting transformer is not your average home-sized unit; it is usually found in commercial landscaping. They are not designed for household usage and maybe only suitable for outdoor use.

80 Amp Landscape Lighting Transformer

The 80 Amp landscape lighting transformer is perfect for medium to large commercial landscapes, or where several fixtures have to be connected. These units allow for more lights per circuit and can handle larger wattage lights.

100 Amp Landscape Lighting Transformer

The 100 Amp landscape lighting transformer is the type to use when higher wattage lights are used, or in very large commercial landscapes where many fixtures need to be connected for maximum output. In addition, it will power stringers with multiple sets of lights.

120 Amp Landscape Lighting Transformer

The 120 Amp landscape lighting transformer is for very large commercial landscapes. They allow for more wattage lights, a high number of fixtures and larger distances between the transformer and the end of the line/fixtures. It is also suited to powering stringers with multiple sets of lights.

The 120 Amp also allows for more wattage lights, a high number of fixtures and larger distances between the transformer and the end of the line/fixtures. It is also suited to powering stringers with multiple sets of lights.

There are many things that you need to keep in mind when shopping for your landscape lighting transformers. Here are some factors that can help you:

  • If the transformer is located close to the lights, then its size will be relatively smaller than that same light at a greater distance from it.
  • Take into consideration the number of fixtures and the wattage of each fixture. The larger your property, the more likely you’ll need a larger transformer. If you have twenty lights that are 50 watts, then your transformer will need to handle a total of 1,000 watts. A 100 amp landscape lighting transformer can handle up to 2,500 watts while a larger 120 amp model can handle up to 3,300 watts. Also consider how long you plan on leaving the lights on each night and weather conditions for where you live. If you’re in a very wet area, you will want to use lights that are more resistant to water.
  • If you plan on powering stringers and other attachments to your landscape lighting system, then you’ll need a higher wattage transformer than if you were just using wall packs or spotlights throughout the landscape.
  • A high-quality transformer can last for several years. When you choose a landscape lighting transformer, it is important to consider the reputation of the manufacturer and how well they stand behind their product.

How long Do Landscape Lighting Transformers Last?

High-quality transformers can last for several years. Consider your options and do your research before making any final decisions on which type of transformer is right for you or your business. Be sure to check with an electrician before making any purchases.


As there are plenty of types of transformers out there, you might be wondering which one is right for your budget and business/home landscape. Here are some types of transformers that are available on the market today:

1) String Isolator Transformer

These are typically small in size and are great to use with string light systems. They control power to the lights in the stringers.

This means individual 12-volt transformers power each light in a line of string lights, allowing you to control all your strands at once rather than one by one. Many are small enough that they can be hidden away or disguised as another item.

The end of the strand is usually hooked directly to a transformer that is then plugged into an electrical outlet. Once the light strands are connected together, you can use one single switch or remote control to turn all of them on and off.

2) Dry Location Transformer

This type of transformer is designed for outdoor use and can handle exposed wiring in weather conditions where water may be present. It is best used for electrical items that are not directly in the ground.

3) Wet Location Transformer

Just like the dry location transformer, this type of transformer can handle exposing wires and is designed to be used outdoors. The main difference between the two kinds of transformers is that this one can work with wet locations, including underground. It is important to note that this type of transformer is larger than its counterpart.

4) Hardwired Transformer

This type of transformer can be installed directly in the ground, rather than plugging it into a socket somewhere else on your property. This is a great way to handle wiring within an underground irrigation system or other locations where you do not want an above-ground transformer. This type of transformer is usually used indoors or underground and can be hard to access once installed.

5) Power Inverter Transformer

Also known as a plugged-in transformer, this type of transformer attaches directly to an electrical socket (usually 110 volts) and allows you to run low voltage lights from the outlet. This is a great option if you are wanting to make your own custom lighting system without having to mess around with any wiring.

6) Power Inverter Transformer Bundle

This type of transformer allows you to use the power inverter together with adapter cords, allowing you to attach up to three single-outlet transformers at once. This helps to eliminate the need for multiple outlets and can be a great option for areas that have limited electrical sockets.

It also helps cut down on additional wires running from battery packs or other devices, which can lead to tripping hazards if not well-planned out.

7) Line-voltage Transformer

This type of transformer is a traditional outdoor transformer and can be used to power up to six lights at once. The transformer operates on line voltage, which is the average amount of electricity that comes into your home or business from an electrical company.

It should not be connected directly to any other light strands, as it is designed only for short-range outdoor lighting.


My goal in this post was to help you determine the size of the transformer that you need for your outdoor landscape lighting. As a general guide, a transformer is what converts 110 volts to 12 volts or 24 volts, depending on the type of lights you are using. The larger your transformers are, the more wattage they can handle.

So if you have a large yard with many light fixtures, it would be wise to purchase a higher voltage transformer so that all of your bulbs will work at their full potential.