Mike Dolt Enterprises
Mike Dolt Enterprises
User: mphillipps, Location: Jersey Shore
Asked on: Sunday, April 3, 2011 at 7:25 pm EDT
Answered on: Tuesday, May 14, 2024 at 3:42 am EDT
Question: I'm planning a 4-way lighting system for pathway garden lights. The line and load sides are ~250' apart. The load is going to be a 120v/500 watt transformer for low voltage lights.My calculation for VD is 250', 15A, 115v using #12 is 12.9%. If I were to #6 I could get the VD down to 3.2%.I don't want to us 500' of #6.Should I consider using a buck boost transformer.Any suggestions world be helpful
Using a Buck-Boost Transformer
Yes, using a buck-boost transformer is a good solution to reduce voltage drop and allow you to use smaller wire gauge.
Benefits of Buck-Boost Transformer
Regulates voltage to maintain a constant 120V at the load, regardless of voltage drop in the line. Allows you to use smaller wire gauge, reducing the material cost and ease of installation.
Calculation
To determine the appropriate buck-boost transformer, you need to calculate the total voltage drop (VD) in your system.VD = (2 Distance Current Load) / (Voltage Conductor Resistance) Distance = 250' (line and load sides) Current = 15A (load current) Load = 500W (transformer load) Voltage = 120V Conductor Resistance = 0.015 ohms/ft for #12 wireVD = (2 250' 15A 500W) / (120V 0.015 ohms/ft) = 12.9%
Transformer Selection
To reduce VD to 3.2%, you need to find a buck-boost transformer with an output voltage of 124.5V (120V + 3.2% VD). The transformer should also be rated for at least 500W.
Suggested Buck-Boost Transformer
MEAN WELL DR-500-124 Output voltage: 124.5V Power rating: 500WAdditional Considerations: Use #12 wire for the line side of the transformer. Use #14 wire for the load side of the transformer, since the current will be lower. Install the transformer as close to the load as possible. Consider using a surge protector to protect the transformer from voltage spikes. Flag for review