Whether you are looking to do it yourself, or have a professional outdoor lighting company design and install it for you, it is important to understand the basics of proper landscape lighting wiring. Having some basic knowledge will help you easily determine how well a company may be installing their systems. You will be able to ask a few simple questions and determine if a company is taking shortcuts in their installation. If they are taking a short cut in one aspect, most likely they are taking short cuts in other areas. This may not make much of a difference for the first couple of years, but if you want to invest in a system that will still look great 10-15 years later, then this information will help you out.

The first wiring configuration is a simple daisy chain. In this case a wire is run and each fixture is simply connected on to the wire as the wire goes by each fixture. This is the simplest and most basic wiring system. If you have read my post on choosing the right fixture, the typical bullet light that is so commonly used comes with an 18″ lead of wire. This fixture then has a “pinch connect” or cheap wire nuts that are used to tap into the main wire.
The benefit of this configuration is the simplicity of it. The major drawback to this wiring system is the voltage drop. You may have seen a home facade with architectural lighting and noticed that it is much brighter on one side of the home than the other. This happens when someone does not use the right wiring system and when they have a transformer that is not powerful enough to make certain that each light will be at the 11.0-11.4 voltage range. On the daisy chain system the first light is going to receive more energy and burn brighter than the last light. If they are a very short distance apart, it is sometimes not that noticeable, but in longer wire runs this becomes more pronounced.
You also have more connections with the daisy chain method. Each connection represents a weak point that can be a potential problem down the road. If the company is using simple pinch connectors, you can expect a 10-15% failure rate over a ten year period. If you have 40 lights, you may be looking at 5-6 service calls to fix this problem. If the company you chose to work with was $500 cheaper, but used a daisy chain wiring system, you have to take into account the additional cost and time of fixing the problems that will come.

The second wiring configuration is a T-wiring system. In order to compensate for the voltage drop installers begin to run the main wire to the middle of the fixtures it is powering. This wire diagram then looks like a “T”, hence its name. This does reduce the voltage drop to the last fixture, but it does not help with the number of connections that will be used. It actually adds one additional connection for each main wire. Your lighting project will look better with a T system, but you will still have the same, if not more, service issues in the future.

There is yet another system, a “loop” method that was used in the past, but since it is used so infrequently today, creates polarity problems, and does not solve the connection problem, I will not spend time on it unless someone really wants to hear about it. (If you do, please write me a comment on this post, and I’ll be happy to give additional information on this).

The fourth and best wiring system is called a “hub” system. On this system each fixture comes with a 15′-20′ lead of wire. The main wire is run to the center of the fixtures. All the fixtures’ wires are run to this main wire and all the wires are connected. You can think of this as spokes on a bicycle tire, the only difference is that there will only be 2-4 fixtures for each hub. Rather than having a connection at each fixture, you now only have one connection at the hub. This dramatically reduces your connections and potential problems.

There are manufacturers who believe it is best to keep the connections above ground. They use a PVC pipe with a top on it. Each hub then is 2-3 inches above grade. It is not totally out of the elements, but it is protected. I believe it is better to simply use a true underground connection that is designed to be waterproof and last underground. This allows us to hide the connections so that you do not have pipes sticking up all over your property and it actually does a better job protecting the connection.  I spent over 5 years researching and finding the best connections available.  Since I have had competitors coming to our blog, I do not share that specific information here, but my installation team and I use them on all Outdoor Lighting Perspectives of Northern Virginia installations.

Besides the overall durability of the system being much stronger, you also have the most even voltage distribution possible. It does not matter if the lead wires are 20′ or 5′ as long as they are all the same distance from the hub.

So to sum everything up, if someone is coming to your home:
1. Find out which type of wiring system they will use.
2. Find out how powerful the transformer is. You will want at least a 12-15 volt transformer and many transformers should range from 12-22 volts to ensure that each fixture will end up at the same voltage when the job is complete.

The more educated you are in the process, the quicker you can weed out the contractors that truly have no clue what they are doing, and compare companies to ensure you are getting the best value for your hard earned dollar.