A Guide For Yardlights.
If you have a yard light and you want some info for selecting one and maintaining them, it depends on which one you have. Let's take a look at some various kinds:
Bucket lights are a staple for residential yard lighting and rural street lighting. Here's an example of a bucket light.
They are fairly easy to maintain, due to their design. One of the most common troubles with bucket lights (due to a lack of maintenance)
is a large amount of bugs in the bucket assembly. This can be easily solved by wiping the refractor (the patterned clear part)
down or by spraying it. Don't forget to turn off the power! Another common problem is a bad photocell(light control), and this can cause problems such as dayburning,
which is when the light stays on during the day. A new photocell will fix this issue. For other problems (such as a loud fixture) I recommend going to a lighting forum and stating your problem there. I like lighting-gallery.net. When selecting a bucket light, look for ones that use a 12-inch bucket and use latches to hold the bucket assembly,
those are the high quality kind. The others use 9 inch lenses and screws to hold it on, you generally don't want them unless it uses a mercury vapor lamp and mogul socket.
Cobraheads are commonly used for lighting roadways and sometimes large areas. Here's an example of a cobrahead.
Usually, the most you will need to do with them is change a lamp or sometimes clean a refractor. Regarding optics,
cobraheads come in many options. The first step in deciding what optics you want is to figure out where you want it. For yards or
large areas, type 3 and 4 are ideal. But for roadways, type 1, 2 and 3 are recommended.
Then you want to figure out if you want drop-lens or FCO. Here is a comparison between them:
Drop-lens: Provides the best light control, but with increased skyglow compared to FCO.
FCO (flat glass): Crummier light distribution, but with almost no skyglow.
What is skyglow? It's when light shines into the sky, creating a glow. Astronomers don't like it, as it's harder to see stars when skyglow is present.
Another consideration for a cobrahead is what size to get. There are 3 sizes, small, medium and large. Small ones can use up to a 250 watt lamp.
Medium-sized ones can take a 400 watt one. Large cobraheads can use a 1000 watt bulb. Small cobraheads are the most common size for small to medium size roadways.
Medium-sized ones are most commonly used for big roads, highways, and parking lots. Large size versions are often found in big parking lots and sometimes large roadways, but they are getting rarer.
What kind of lamp (and ballast) will your yardlight use? Some common options include HPS, MH/PSMH, and MV.
HPS (High Pressure Sodium)
High pressure sodium lamps are probably the most common bulb type used in streetlighting, as they provide high efficiency light while being relatively inexpensive. HPS bulbs require a ballast and ignitor/starter. They have a distinct yellow-orange color.
MH (Metal Halide)
MH bulbs are popular for indoor areas and for outdoor floodlights. It makes a white light that's sometimes better than LED.
Metal halide comes in two varieties, probe-start and pulse-start. Probe-start is probably the most common kind of MH lamp.
It works by having a starting probe in the arc tube. However, this often causes color shifting. Due to this, pulse-start lamps are getting more popular.
It doesn't have a starting probe, so it has to use a high voltage to strike an arc. For streetlights, pulse-start is used.
MV (Mercury Vapor)
Mercury vapor was once extremely common for outdoor lighting, as it is more efficient than incandescent and was relatively inexpensive.
Before 2008, you could get MV fixtures. Today, if you want a MV fixture, you can use a MH ballast without ignitor, but this trick only works for wattages 175 watts and up.
If you're unsure what to do, send me an email.
You can also use a HPS ballast without ignitor, but only if the ballast and lamp are at least 250 watts. You also have to match the wattages.
Clear MV bulbs create a white light with a hint of blue and green.
Phosphor-coated ones usually make a warmer light, with higher color rendering capabilities.
Mercury vapor is sometimes seen as inefficient, but it's worth it if you desire the unique light that it makes.
There's always more info to come, so stay tuned.
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