“Hi. I’m Craig Bryant with Bryant Electric Service, and I’ve been in business in Austin for almost 30 years now. I’ve been asked by many people a lot of different things about electrical work, and so I hope I can help with answering some of your questions as well.

OK. I’ve been asked many times about the difference between aluminum and copper wire, and the biggest difference is that copper is just a lot more stable metal than aluminum. And electricity, the biggest enemy to electricity is heat. The hotter it gets, the more important it is to have a stable metal. Aluminum is good but not as good in that in the long run over many years or decades because the instability of aluminum, when it heats up it contracts and expands. As it cools down, it contracts and heats, it expands.

So that happening over time over years and decades especially at your main service or wall plugs or something then that causes a loose connection and it starts arcing and the arc can create a fire over time. That just doesn’t occur in copper ever if it’s installed properly and it’s real tight at the beginning when it’s installed.

So the other problem with aluminum is oxidation. As they’re both exposed to air, copper oxidizes as you can see when it turns green, but it doesn’t affect the connection of the wire. Whereas aluminum, when it oxidize, it creates this crust that builds on it. And you’ve probably seen it before, but this crust can sometimes get as much as a quarter inch thick. And besides the fact that the metal is not as compatible to the heat and temperature problem. With that crust building up, it will also create a gap between the connections that can cause an arcing.

So copper is always better than aluminum and everything except price. And the main reason that it’s being used is because it’s so much cheaper.”

relatively high ceilings. Drive by any industrial park, warehouse, or factory, and walk inside and what you will see is a high bay light.

But walk into any factory or warehouse and you will see different styles and options, wattage’s and configurations. Traditional high bay fixtures that were once common place were Mercury Vapor, which were then replaced with High Pressure Sodium and Metal Halide bulbs. As new technologies were introduced, and old technologies became more common, the old HID bulbs were replaced with Induction and Fluorescent light sources. And more recently with the more wide spread approval and popularity of LED, we started to see conversions from these older technologies to the latest energy saving LED High Bays.

A High Bay Fixture, depending on the light source, can take on many forms and shapes. If you consider a Metal Halide or High Pressure Sodium fixture, they typically consist of a large heat sink block at the top of the fixture that typically houses the fixtures ballast. Below is an aluminum or acrylic dome and at the top of the dome is the HID bulb. These bulbs typically come in two wattage’s, 400 and 1000. 400 Watt Fixtures tend to be installed in ceiling heights no higher than 30 feet, 1000 watt fixtures are typically 40 feet or higher. Interestingly enough, spacing of lights is similar to the height they are located off the floor. A fixture installed at 20 feet from the floor is installed in a 20X20 pattern, 30 feet in a 30X30 pattern, 40 feet in a 40X40 pattern. Of the 3 type of HID bulbs, Metal Halide tends to be the best option. High Pressure Sodium Bulbs are very low on the temperature color and have the warehouse aisles have the ability to focus the light where it is needed. A light designed for a warehouse aisle is a lot different than a light designed for a gymnasium or a factory floor. In these spaces, a light that can flood the area evenly is important, in a warehouse aisle, a light that can light up the face of the shelves and the floor below is important. And when selecting energy efficient options, its just as important to understand the technology and what it is capable of doing. Adding controls to a T5 fluorescent fixture is a good idea only if the ballast is designed to handle that requirement and not lower the life expectancy of the bulbs. Motions sensors and daylight controls that dim the light output based on occupants and the amount of daylight available in the space. Technologies such as metal halide and high pressure sodium are not a good choice as these technologies are not good at dimming or turn on or off quickly. Fluorescent can dim, but you need special ballasts for them. So knowing what you want to do and may want to do is important at time of purchase, because not having the proper equipment or options could mean a costly lighting warehouses, factories, gyms and readily available through the utility companies, and mass adoption means the technology of LED had matured to the point where the questions and disbelief of past years have gone away.