Issue #1: I bought a 60W LED power supply (aka. LED driver). Why do the instructions indicate that I can only draw 30W from the IT on a hot Summer's day?
An LED driver is usually rated under certain test conditions. It is a common industry practice to rate the output power level in 25 degrees C ambient temperature. However, an outdoor LED signage is usually facing a much higher ambient temperature on a hot Summer's day. The temperature can go as high as 45 degrees C in some sunny, desert states, such as Arizona and Nevada. In this situation, the output needs to be restricted so that the power supply itself can work under a less stressful condition and creates less heat. It is recommended to follow the output de-rating curve provided by the manufacturer to determine the maximum allowable drawing current in real world conditions.
Issue #2: My LED power supplies is going to be exposed to the air. Do I need to place it in an extra waterproof enclosure?
If the LED driver used is not design with true waterproof feature, an enclosure is definitely needed. The moisture in the air will eventually rust the case, get into the circuit board, short the circuitry, and create a hazard. There are true waterproof supplies available on the market. It is usually equipped with a fully sealed case with water and rust resistance paint on the outside. There are also water-tight connectors and the conduit used on the input / output wiring to make sure the moisture cannot leak into the case on the wiring interface. Look for the UL1310-Wet or the UL50 certificate from the manufacturer. It is the certificate UL (Universal Laboratory) grants to the manufacturer if their product passes the wet location usage test.
Issue #3: My LED power supply carries IP-66 certificate. Why does UL not recognize the certificate?
IP certification is granted by the European community. It is a pioneer regulation in determining a product's ability to survive in different dusty and wet conditions. However, UL does have its own set of standards by which it regulates the products sold in the US. If the whole outdoor LED signage system needs to acquire a UL certificate, it is better to implement an LED driver which meets UL's regulations, to avoid additional testing. UL879 is the regulation applied to the outdoor LED signage power supply. Because the power supply is not an end product, it can only be recognized, but not certified by UL.
Conclusion: The LED technology has been recently adopted in the LED industry. Because of the fact that it is a relatively new technology, there are myths about choosing the right LED driver to use in the signage. The top 3, most frequently asked questions about the LED power supply are answered in the article.
An LED driver is usually rated under certain test conditions. It is a common industry practice to rate the output power level in 25 degrees C ambient temperature. However, an outdoor LED signage is usually facing a much higher ambient temperature on a hot Summer's day. The temperature can go as high as 45 degrees C in some sunny, desert states, such as Arizona and Nevada. In this situation, the output needs to be restricted so that the power supply itself can work under a less stressful condition and creates less heat. It is recommended to follow the output de-rating curve provided by the manufacturer to determine the maximum allowable drawing current in real world conditions.
Issue #2: My LED power supplies is going to be exposed to the air. Do I need to place it in an extra waterproof enclosure?
If the LED driver used is not design with true waterproof feature, an enclosure is definitely needed. The moisture in the air will eventually rust the case, get into the circuit board, short the circuitry, and create a hazard. There are true waterproof supplies available on the market. It is usually equipped with a fully sealed case with water and rust resistance paint on the outside. There are also water-tight connectors and the conduit used on the input / output wiring to make sure the moisture cannot leak into the case on the wiring interface. Look for the UL1310-Wet or the UL50 certificate from the manufacturer. It is the certificate UL (Universal Laboratory) grants to the manufacturer if their product passes the wet location usage test.
Issue #3: My LED power supply carries IP-66 certificate. Why does UL not recognize the certificate?
IP certification is granted by the European community. It is a pioneer regulation in determining a product's ability to survive in different dusty and wet conditions. However, UL does have its own set of standards by which it regulates the products sold in the US. If the whole outdoor LED signage system needs to acquire a UL certificate, it is better to implement an LED driver which meets UL's regulations, to avoid additional testing. UL879 is the regulation applied to the outdoor LED signage power supply. Because the power supply is not an end product, it can only be recognized, but not certified by UL.
Conclusion: The LED technology has been recently adopted in the LED industry. Because of the fact that it is a relatively new technology, there are myths about choosing the right LED driver to use in the signage. The top 3, most frequently asked questions about the LED power supply are answered in the article.
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