LEDs are an excellent choice. But they come with a few “gotchas” (which we’ve been covering). Here’s another: you must pay careful attention to voltage drop. With LEDs, it’s not just an efficiency issue. It’s a survival issue.
In contrast to other low voltage lighting choices, LEDs are extremely sensitive to undervoltage (and to overvoltage). Some ways to address this issue:
- Calculate the voltage drop for your runs, and upsize conductors to compensate. Note that oversizing a conductor won’t increase the voltage, but undersizing it will decrease the voltage.
- Multiple tap transformers are often used to solve this problem. With other low-voltage lighting, wrong selection usually isn’t harmful. With LED systems, you must be very careful to select the right tap.
- Look for a packaged power distribution system that will work with your particular LED products; you may find one designed specifically for them and for the application in which you are installing them.
- Make the runs from the DC source as short as practical. Consider distributing smaller DC sources rather than distributing DC to all points from one central source. This will usually cost more in parts and labor, but in addition to mitigating the voltage drop problem it decreases the outage area in the event of a power supply failure.
- Minimize the number of connections between the power supply and the device (to zero, if possible).