A complete low voltage landscape lighting system consists of many components: low-voltage transformer(s), direct burial cable, waterproof wire connectors, and luminaries rated for outdoor use. However, the transformer is arguably the most important piece of any system. Not only does the transformer convert line-voltage electricity (120V) to safe low-voltage (12V), but it will also serve as the main control device of a lighting system and should offer: durability, reliability, simple installation and ease of use.
Selecting the correct low voltage transformer for a project is key in allowing a landscape lighting system to functional properly and will also help minimize issues with lights failing due to incorrect voltage input or faulty wire connections.
If you’re looking for help with understanding AMP®’s low-voltage transformers and how to select the best transformer for your upcoming projects, continue reading for some key features to consider.
AMP® Low-Voltage Transformer Styles
AMP offers three distinctive transformers styles, each offering unique benefits to consider:
Slim Line Transformers
AMP® Slim Line transformers are specially designed with compact housing for low-profile installation on the exterior of a residential or commercial building. Transformers typically aren’t manufactured with aesthetics as a top priority — the easier it is to conceal a transformer during installation, the cleaner and more refined the layout of a system will be upon completion. Various control options for internal timer devices are available, including traditional mechanical timers and photocell timers for dusk-to-dawn settings. This allows for flexible control capabilities based on the application. In addition to the compact design, Slim Line transformers also offer utility patented clamp-style wire connectors. These connectors are quick and easy to use and allow for secure, gas-tight wire connections without the need for tools.
The one small drawback to the compact design is capacity. For commercial projects, Slim Line transformers are not offered in larger models (600W, 900W, or 1200W); the physical designs required for these capacities would defeat the purpose of the unit being easy to conceal.
Overall, AMP®’s Slim Line transformers are quick and easy to install; they feature easy-to-conceal designs; and offer traditional, non-complex control devices. These transformers are ideal for most small-to-medium-sized landscape lighting projects.
Clamp-Connect Transformers
AMP® Clamp-Connect transformers offer the same quick and easy-to-use, clamp-style wire connectors available in the Slim Line series. However, higher capacity versions are available for larger projects (600W and higher).
Clamp Connect models offer control options similar to Slim Line transformers with traditional mechanical timers or photocell timers for dusk-to-dawn settings. Digital timers and select outdoor-rated Bluetooth/Wi-Fi-enabled timers can also be used in the internal timer socket within the Clamp Connect transformers.
The main benefit of Clamp Connect transformers is the time they save contractors during installation, troubleshooting, or expansion. Wires can easily be inserted into taps during installation, easily removed for troubleshooting, or easily adjusted to account for expansion per a client’s request — all without the need for tools. The reliability and speed of the clamp-style connectors make these transformers extremely popular for most landscape lighting projects.
Multi-Tap Transformers
Low-voltage transformers with traditional screw-style wire terminals are still widely used in landscape projects. Though old-fashioned, these classic designs offer unique benefits. The main benefit is, of course, related to the wire terminals.
The one limitation of clamp-style wire connectors is the number of wires you can securely insert into the wire taps; only one wire should be inserted per clamp with a maximum wire gauge of 10AWG. With a screw-style wire terminal, you can insert and securely fasten more than one single wire (the exact number will vary largely based on the wire gauge(s) used). This allows for an increased number of wire runs, providing flexible design options that give contractors more creative control over their landscape lighting designs.
Overall, traditional screw-style transformers may require tools and a bit more labor when securely inserting wires into the terminals, but they allow for an increased number of runs for endless design creativity while still offering flexible control options. These transformers are tried and true and will likely remain a staple of the landscape lighting industry for many years to come.
Determine the Capacity
After establishing your preferred style of transformer, you’ll need to determine the general capacity needed for your project. To do so, you will need to add up the total combined wattage of all fixtures being used; this includes the total wattages of all bulbs used, as well as the wattages listed for any integrated LED fixtures. As a general rule, total light fixture wattage should not exceed 80% of transformer capacity. This number should be 20% less than the transformer’s wattage capacity.
For example, let’s assume a proposed design includes 14 spotlights consuming 5W of power each and 10 path lights consuming 3W of power each. The total combined wattage in this scenario would be 100W. So, a single 100W transformer would not be recommended for this – a secondary or larger transformer, such as the 150W model, would be required.
