A quick, inexpensive yet durable method for making an outdoor wiring connection.
Sample Fixtures With Less Than 25′ Lead Cables
The Problem – Fixture Cable Needs to Be Longer
So you are using the hub method of wiring and not all of the fixtures in the design you are installing have lead cables long enough to reach the intended hub location. So, one or more fixture lead cables will not reach the intended hub location. You could extend the Home Run (HR) cable and add another hub location. But what if it is a fixture that is rain gutter mounted to illuminate a dormer, second story gable or attractive chimney and the fixture cable only reaches to somewhere in the middle of the downspout? I’ll describe a method of creating a robust (electrically, physically and hermetically) connection in this article.
A quick and inexpensive way to make a solid electrical connection is to use a corrosion resistant non-insulated “Butt Splice”. These connectors that allow the 2 ends of the connecting wires to “butt” up against each other are also known as “Barrel Connectors” or “Butt Crimps”. The insulated version for hobbyists and technicians doing repairs in protected areas are very common. When performing a connection that will be in the earth or exposed to water it is important that the connection be corrosion resistant, well protected from moisture and not easily separated if the cable gets snagged whilst someone is working nearby.
A Brass Butt Crimp Type Connector With a Tin Coating for Corrosion Resistance
The description I am provided is detailed and a bit lengthy but the actual process is quite quick for someone who has made a few of these simple connections. You may jump to the video at the end of the article if you want a quick visual summary.
What will I need?
The tools you will need are a wire stripper, proper crimper and a heat gun. (A separate post will be made for Tools use for low voltage lighting)
Examples of 2 Types of Crimpers – Note the One on the Right is Favored as it Accepts Two Sizes of Crimps
The supplies you will need are the proper size butt crimps, proper size double layer heat shrink and UV resistant nylon wire ties.
The marked and unmarked wires are separated and the ends stripped of insulation in preparation for connecting. Only strip enough to allow the wire ends to reach the mid point wire stop in the butt crimp.
Slide the shrink tubing over one end of each of the wires. If you forget to do this, you will have extra practice stripping and crimping. 🙂
Carefully slide the butt crimp over one stripped wire and crimp the connector with the crimper center between the mid point wire stop and the end of the butt crimp. Repeat this for the connecting wire.
The butt crimps are available in different sizes to accommodate various ranges of wire sizes. The same for the heat shrink tubing. In this example the wire is 16 AWG No-Ox Low Voltage Landscape Lighting wire and the splice is an Ideal #14-#16 size. The heat shrink tubing is a 3/16″ ID size.
Slide the shrink tubing over the crimped connection and center with the butt crimp. Using a heat gun begin heating the shrink tubing starting at one end and working towards the opposite. Provide heat around all sides of the shrink tubing. There is an adapter for many heat guns that distributes the heat around the wire more uniformly than an open ended one like I use. (I’ll add details about this in the Tools post that is forthcoming)
More on Connections
In a separate post I will cover other types of connections such as connecting to an existing hub circuit and making a repair to a damaged cable.
Alternative ways to connect two wires together. (Forthcoming)
I feel the best way to assure a solid and durable electrical connection is to solder the connection. The most efficient way to do this is to use a solder pot. Trust me, I have tried other methods such as a micro torch and a high output soldering gun. They are SLOW and cause minor degradation of the insulation. Once the connection is soldered it is covered with a dielectric grease filled, direct burial wire nut. The wire nut does not serve to hold the conductors together, that is done by the solder. But, it prevents the conductors from creating a short circuit by directly touching another conductor or contacting a conducting surface. Plus, the dielectric grease seals the end of the wire to prevent wicking of moisture into the stranded wire causing a slow degradation of the conductors.
Here’s the steps I follow. They may be confusing but the pictures and short video may prove helpful.
If the HR cable is looped at this point, cut it at the loop to create two ends. Separate the 2 wires of all cables (HRs and fixture) to about 10″. Strip the ends of all the MARKED wires back 1-1/4″. Place a wire tie snuggly around this bundle of wires. Repeat the stripping and bundling for the UNMARKED wires. Focusing on one bundle at a time, carefully align the insulation ends of each wire in the bundle. Once these are aligned, carefully and firmly twist the conductors together. Snug the wire tie to help limit movement of the prepared bundle. I place a length of stretchy electrical tape snuggly around the bundle at less than 1″ from the ends. The tape acts like a sticky rubber band to hold the stripped ends in alignment and prevents the twisted conductors from unraveling. Repeat this for the second bundle. Additionally, you may place a standard, indoor type of wire nut on each twisted group to temporarily hold the conductors together.
Marked and Unmarked Wires are Separated and Bundled in Preparation for Soldering
Two HR Cables and Four Fixture Cables in This Prepared (for testing and soldering) Bundle
This process is repeated for each location of a hub. Once all hub location wiring connections are prepared, the system may be tested by connecting the HR(s) to the transformer and applying power. Once all the fixtures are verified to be functioning, the power may be removed and the connections soldered.
Soldering is a very quick process once the solder pot is up to temperature. I recommend preheating the solder pot for 30 minutes before you are ready to begin soldering. Cold, windy weather conditions will require even longer preheat times.
The soldering process is simple but respect for the fact the metal is molten (very hot) is very important. Wearing safety glasses and gloves is recommended. Different types of solder may be used. The most common is 60/40 lead/tin (60% lead & 40% tin) so understanding the importance of using heated lead in a ventilated area is important. Even more important is to not allow the lead to get in your mouth. Sounds like a strange thing to say but lead on your hands can find it’s way into your mouth if you grab a sandwich after handling lead without washing your hands, for instance. Flux is also a material you want to keep out of your body along with the fumes it generates when heated. So use sensible practices and read up on these two materials.
The flux is applied to the ends of the bundled conductors about half the size of a BB by dipping the conductors into the flux. With the solder pot very close to the bundle, insert the fluxed conductor bundle straight down into the center of the molten solder up to the insulation but not touching the insulation. As the conductors reach temperature you will notice that the solder intimately contacts the conductors and begins to wick up the strands. The video below demonstrates this process.
By cutting into a soldered connection it is visible how solid this connection actually is.
Dissected Soldered Hub Connection
If a system is expected to be expanded at a later date a 12 – 18″ length of HR cable may be soldered into the bundle and capped for later use.
The hub method reduces the number of connections to the HR cable which saves installation time and soldering at the connections greatly improves reliability of the wiring system.
More on Connections
In a separate post I will cover other types of connections such as extending a fixture cable, connecting to an existing hub circuit and making a repair to a damaged cable. (Forthcoming)
Installing a PVC Sleeve Under a Walkway to Allow Passing of a Home Run Cable to Another Garden Bed
First things first. This guide is not, in any way to be an interpretation or substitute for rules that govern any geographical locations specific requirements related to low voltage lighting. The intent is to help one be efficient at installing robust low voltage lighting systems.
A Couple Points on Terminology
I tend to use the terms cable and wire interchangeably. A wire is technically a single conductor item and a cable is a multiconductor item. Please be aware of this. I also call a fixture with a light source in it a fixture when technically the fixture is what holds or contains the light source (technically an illuminant, but who says that!) and the fixture with a light source (illuminant) installed is a luminaire. In my defense, who rotates only their tires?
There are several steps that may be completed BEFORE you even get to the job site. This will save you precious time in the outside world. This is extra important if you are working in the late fall and winter when daylight is less abundant.
Here are preparation tasks to consider: populate the directional fixtures with the light sources then label them to match your lighting design document (more on this in a separate topic), gather up and wire tie your “extra” wire near each fixture (I typically leave 2-3′ for extra wire at each fixture for future repairs or relocation), charge and set any programable controls such as digital time clocks, check that you have all your consumables (such as wire label, wire nuts, wire ties, hardware, etc.) on hand for the job.
Place the Fixtures
The first item to get out of the way is to place the fixtures where they will be mounted. This is NOT installing them, but getting them where they will be installed. If you have an assistant, they may follow you and start mounting the fixtures where they will reside. I typically place the fixture with the mount resting EXACTLY where I want to be. This way my assistant knows precisely where to mount the fixture. You may use flags as well. Flags will allow you to pre-mark the location before the install day simply by putting the fixture number on the flag. Hardscape mounted fixture locations may be marked using tape. Tree light fixtures and gutter mounted fixture locations can be pointed out using a laser pointer.
Pull the Cable
Since I predominately use the “hub” or “spider splice” method of wiring (more on this in a “connections” topic) I pull the fixture cables (typically a 25′ lead) from a group of no more than 6 fixtures within a 40′ diameter area to a central, convenient location. This will be where my home run (HR) cable (from the transformer) will connect to this group of fixtures. I create a gentle “knot” with these (up to 6) fixture cables so that they do not get separated or pulled from the hub location.
Home Run Route From a Backyard Through a Crawlspace to the Front Yard
I repeat this process for all the fixtures. When done, I have identified where my HR cables will connect to each group of fixtures. If a hub location will have a pass through HR cable (power continues on to another hub) I limit the number of fixtures connected to that hub to 5. More than that and the bundle becomes too large to allow the installation of a wire nut.
With the spool of home cable (HR) (typically 12 AWG, 2 conductor, Low Voltage, Underground Feeder) placed at the transformer location (mounted so that it can rotate, there are several methods) I label the cable about 10″ from the end with a wire marking label. I then proceed to pull the HR roughly along the path that I would like the wire to be buried. Typically I will follow the foundation of a home or other hardscape edging. The goal is to intersect each of the hub locations. This usually requires the HR to loop out into a planting bed from the hardscape edge to make this intersection. Leave at least 18″ of extra HR at each hub location.
3 Hubs (or Spider Splices) in a Home Run Circuit
Make the Connections
This is the critical part in satisfying the physical requirements of the electric current. You will want to make robust and reliable connections at the HUB that will survive the aggressive environment they will be in. The hub method of wire is the fasted method to install a lighting system and it results in a very low number of connection points.
This section deserves much detail so it is covered fully in the Connections post
Mount and Connect the Transformer
This is a straight forward process. The location is determined by where there is available electrical power from a GFCI protected outlet, a location that is not going to cause an eyesore and is close to the area where the fixtures will be mounted. This could be inside or out. Common indoor area are garages, crawlspaces and utility rooms. However, the most common location is outside on the end or back side of a home. Transformers should NOT be mounted directly against vinyl siding as they can get warm enough to melt the siding in certain applications. The bottom of the transformer should be 12″ or more above the ground surface.
Most professional grade transformers will have at least one top and bottom mounting screws. A simple method to mounting the unit is to locate and install the top screw, hang the transformer by the top screw, plumb the transformer, mark the location of the bottom screw and install the bottom screw.
I will say that there are times when I locate the transformer and then remove it and lay it on it’s back to make the wiring connections. I find that this gives better access and a better view of the low voltage terminal blocks.
Out of Eden Employees Working a Project in Maryville, TN
If you are using conduit to guide the low voltage from the soil to the cavity of the transformer, don’t forget to route the HRs through the conduit and fittings in the appropriate order before making the connections.
For consistency, I always connect the marked wires to the common side. This assures that I never inadvertently connect two wires from a single HR to a common (or 12 volt side). This of course results in no voltage on that HR. Teaching your mentees this method helps assure you have less troubleshooting to do.
In most cases I connect all the unmarked wires in the cable to the 12 volt terminal of the transformer when using LED light sources. The light sources I use have a typical operating range of 8 – 25 volts but the nominal voltage is 12 volts. Early on I used the 15 volt terminal but found that I was experiencing more light source failures than expected. I expect that by running at a higher voltage the system was less voltage surge resistant. Of course, having 12 volts at the transformer terminal does not equate to 12 volts at the light source. Voltage drop in the cabling will cause some loss. Since the current in an LED system is very low, the voltage drop is very little. If you have a long, heavily loaded HR I recommend checking the voltage at a light source socket. If it is close to or below the bottom of the voltage range specification for the light sources being used.
Test the System
Now that all your fixture and transformer connections are made, it is time to light the candles! Plug in the transformer and turn on all the circuit protectors in the transformer. All the connected light sources should come on. Verify this by examining each fixture. If it is still light out you may need a mirrored surface to verify pathlights. I use my cell phone and walk by each fixture and hold the phone facing up and look at the reflected image to verify the light source is on. The front facing camera works as well.
The last part of the system to be installed is the control. More on controls in a separate section. I generally leave this out until the system functionality has been verified.
Soldering the Connections
Once all the fixtures are verified the connections may be made permanent by soldering them. This process is covered in detail in the Connections post.
Cover the Cables
Now that the system is verified the cabling may be buried and/or covered. The enclosures for the hub connections (like Spider Splices) may be put in place. The NEC has been requiring a burial depth of 6″ for low voltage underground feeder cabling. If you are working with an assistant this time consuming step may be taking place in part while the connections are being made and the system tested.
Fine Tune the Light
Once the sun begins to dim, it is time to fine tune the system you have just created. Fine tuning can be enhanced by having a second person who stands back a distance and provides feedback while you are adjusting. The view is different when at a distance than when kneeling near a fixture. But, even at the fixture you can see if light being wasted or not. Wasted light is light that is not reflecting off a desirable surface, object or just going into outer space. Architectural lighting seems to be the fussiest about getting the focus or aim just right. Remembering from lighting design 101, one wants to create a continuous path for the eye to follow and to have no glare and no black holes. If the lighting design was developed correctly this should be achievable with careful adjustment of the fixture aim and at most a change in light source beam angle or lumen output. Fixture adjustments should be locked once the aim is established.
New Construction Architectural Lighting Kingsport, TN
Professional Outdoor Lighting does not just happen. There is a concerted effort to visualize the scene after dark and create a plan that brings the visualization to life. It does not matter if you are a DIYer (Do It Yourself – er) or a contractor who works in the outdoor world, there are certain steps you can take to make your project match your visualization.
OK, that was not much of a “Welcome!” but I hope is sets the tone for how this blog will be used. My goal is to publish content on topics related to achieving professional results using low voltage LED landscape and architectural lighting fixtures and light sources.
Design, equipment choices, installation information and tips along with opinions (yes, mine) will be shared. There will also be a few posts on troubleshooting, one of my favorite topics!
Just Garden Geeks 