When it comes to lighting, we are used to lighting that shines from above, like the sun or the moon and many artificial light sources that mostly are used from the ceiling or poles. In my early career as a lighting director for movies and television we used to up light or semi up light certain features or backgrounds in order to create dramatic visual effects. Back When I owned an event lighting company in Israel, I had an opportunity to implement some of what I have learned in the motion pictures industry. Back then there was no culture of lighting for events, the little lighting that was done was mainly halogen floodlights hanging on high poles and flooding spaces with a glaring light. Bringing the techniques I’ve learned in the motion pictures lighting, I have started up lighting trees, bushes, walls, architectural features, backgrounds etc. This created a lighting effect that was beautiful, dramatic and overwhelmed people. During the many evenings and nights that I spent overseeing the events, I used to stand close to the entry to the event location and watch people’s reaction when they entered the space. I noticed an interesting thing, the beauty we created using these special techniques of lighting, was so surprising and “out of this world” that people would just stop in their place, breath deeply with a quiet sigh and soak the view with admiration. That taught me how powerfully lighting can effect human emotions. As I started designing for architectural lighting projects, I carried on my experience from both the motion lighting and event lighting and started using in floor lighting in my designs. The first notable project that this technique was implemented for was around 1992 for the Wailing Wall tunnels in Jerusalem. The effect was surprising, interesting, complementing to the architectural nature of the tunnels, warm and dramatic.

Electricity exists everywhere, from high voltage power lines to phones and computers. Understanding the basics of how it works remains essential to using it safely and efficiently.

When electricity travels from a positive lead to a negative lead in a circuit powered by a battery, it is considered direct current. This type of current powers electronics, LED lights, and cars. Alternating current is generated from rotation, usually by a generator. The direction of the current and the voltage flips as the generator completes a rotation. The faster the generator spins, the faster the flipping of current direction occurs. In North America, the typical frequency of AC power is 60hz or 60 alternations per second. The advantage of AC power is that the voltage can be stepped up easily by use of a transformer, which allows high voltage transmission. AC power is also useful for electric motors.

Specifically, power is a measure of energy usage over time. The standard unit of power is the watt and calculated as P (watts) = V (volts) x I (amps). Utility companies sell electricity in units of kW*h (kilowatt hours), which is simply one kilowatt of power delivered continuously over one hour.

The ENERGY STAR® Partner of the Year Award. Sea Gull Lighting’s focus remains on delivering on-trend, high quality lighting products with unparalleled customer service and best-in-class availability. For almost 100 years, they have built strong relationships and earned a reputation among channel partners, builders, contractors and homeowners to be among the very best. Sea Gull Lighting looks forward to the evolving business landscape, and with its continued commitment to serve, and to listen and learn from its valued customers, is poised for success as it soon enters its second century of operation.

High temperatures cause conductors to expand and hence increase in length. The converse is true for low temperature conditions. The change in length varies from one conductor to another depending on its thermal expansivity. The length of copper conductors, for instance, changes by 5 feet per 1000 feet of length when the conductor temperature changes from 100 – 0°, while aluminum changes by about 7 feet. The length increases with increase in temperature and reduces with reduction in temperature.

This increase or decrease in length is of great concern when installing power transmission lines between poles and towers, or when installing other power connectors. There must be an allowance for this change in length since it can cause catastrophes if it’s not there.

Weather changes are associated with increase and decrease in temperature and thus affect power transmission lines and other conductors. However, change in temperature is only one factor that affects power lines. Below are the changes that occur to power lines and other conductors as a result of weather changes:

The amount of heat dissipated from power conductors is reduced during hot and calm weather conditions. Basically, if the temperature of air around the cable is low, more heat is lost from the cable to the air. If the air is already hot, the exchange of heat is lesser. This low heat dissipation causes the lines to overheat. However, the rise in conductor temperature (overheating) worsens when cables are transmitting too much power than required. The first effect of this increased conductor temperature is snagging, which is the downward bulging of the cable between two poles, caused by the increase in the length of cables.

Snagging is largest during extreme hot weather (largest increase in temperature) conditions experienced in summer. The increase in length results to downward bulging of the cable due to the effect of gravity. Excessive sagging is dangerous if it goes below the accepted height clearance – cables could come into contact with trees, buildings and other structures underneath, causing electrocution and fires.

Excessive sagging represent an added weight on the power line and this increase may cause the line to fail or to pull down weak poles and towers. The effects can be small but gradual and so the poles and towers will finally come down or require some adjustment/replacement after some time, which is costly. This sagging can also cause the lines to short out. Excessive sagging is also costly since it leads to increased electrical resistance. This means that a sagged power line transmits lesser current than it normally does, thus causing under-feeding of electrical equipment and industries. It is also costly and time consuming to rectify a sag.