UV light sources can be built up in all types of configurations and there isn’t a single right way to build it. The main goal is to present the desired UV-C light intensity at the point or points of interest. In this article, we will describe an example build to create a light array using four UV-C germicidal 40W fluorescent bulbs. In this build, we are using Panasonic GL-40 germicidal fluorescent bulbs. They have a rated UV output of 20W each So an array of 4 would have a total UV-C output of 80W. For more of an explanation of how UV-C light sterilizes surfaces, please check this article and the references at the bottom of it..
The Build
For this build, the main things we were concerned with are ease of assembly and providing a stable base and framework to mount the fluorescent light fixtures. To do this, we will use similar framing techniques as you’d use to build a simple wall. This consists of a top plate, bottom plate, studs for support, and a base. For this build, we only used 2x4s since they were readily available.
To start, we first lay out the fluorescent light fixtures to get the spacing down. In this case, we spaced the studs out 30 cm apart so that there is a bit of a gap between the fixtures. Based on experience, you may want to add a bit more spacing between the fixtures. We had trouble drilling a hole through the middle stud to route our wiring through.
Once the stud spacing is marked out, cut the top place so that the edges are flush with the studs. Measure out the bottom place but leave additional room on both sides to attach the stands for the base. When you’re done, it should look something like this.
The two feet that form the base of the lighting array are approximately 1 m long. We’ve found that this provided very stable support and prevented the array from falling backwards or forwards. We used standard 65mm deck screws for the complete build.
Next we mounted the fluorescent lighting fixtures using 35mm deck screws. We located them towards the top end of the 2×4 studs, which were 2m (6 ft) long. The two end fixtures can hold one fluorescent light with the middle fixture able to hold two fluorescent bulbs.
The Wiring
Please note that if you don’t feel comfortable wiring lights up for mains connections, we recommend contacting an electrician or someone that has electrical experience. Also please follow proper safety guidelines for electrical work.
We now need to wire up the fluorescent fixtures in parallel so they can be powered from a single plug. Luckily, fluorescent lights usually assume they will be wired in parallel and come with specific adapters for it. These particular fixtures use quick connectors which means you just take the copper wire from the electrical cable and stick them in.
Before we begin wiring things up, we need to drill an access hole so that we can route the electrical wire through. Fluorescent light fixtures usually have multiple access holes, with a main one near the designated cable connector.
Once the hole is drilled, we routed are cables through the access hole and to the fixture. We then stripped the insulation to reveal the copper wire. For quick release connectors, you just need to stick the wire inside the adapter.
It’s important to stay consistent with your wiring. For whatever color you use for the “hot” wire, use that same wire and color for the “hot” wire on each connector. Same goes for the “neutral” wire.
Since we’re in Japan, we’ll be connecting this to a two-prong outlet which is common in this country. For countries like the US where the third ground wire is common, we recommend to connect the ground as well for safety.
For the end fixture, you’ll have something like this.
Here’s the middle fixture with the parallel connections.
When the wires are connected, you’ll end up with something that looks like this. Each electrical adapter on the fluorescent lights have two sets of connectors. One set is for the incoming wires, one set is for the outgoing wires. This allows for easy parallel connections.
Now that the light fixtures are wired up, we used standard white fluorescent bulbs to test out the connections. Standard 40W fluorescent bulbs are cheap at around $5/ea while the 40W germicidal bulbs are around $20/ea. Once we verified the standard bulbs would light up, we were ready to test out the germicidal bulbs.
We first mounted the reflective shields. We’ll do actual testing to see if these shields reflect much of the UV light and whether or not they contribute to increased intensity at the points of interest. But for now, they also serve the purpose that they hide all the wiring and prevent people from touching it.
Once the reflectors were installed, we put in the Panasonic GL-40 germicidal bulbs.
Turning them on gives an intense Blade Runner glow. While testing and working with UV germicidal bulbs, it’s important to remember to wear safety gear and protective UV-blocking goggles.
Here are some more shots of the build with the UV lights on.
Good luck and please send us pics of your builds. We will be posting them on the Hyjeia Gallery page 🙂