Advantages of a 24-Volt Lighting Transformer
The higher maximum load allowed by a 24V power supply not only increases the capabilities of your lighting system by letting you double the total wattage, but reduces the risk of voltage drop when you are powering a long run of lights.
Just like a 12-volt system, a 24-volt lighting system should not exceed 25 Amps on any single run. But where the 12V system maxes out at 300 watts per run (25 amps x 12 volts = 300 watts), the 24V system can power up to 600 watts (25 amps x 24 volts = 600 watts).
Does that mean a 24-volt transformer can power 4 times as many 12-volt lights?
No. 24-volt transformers should only be used with lights that are rated for 24V. If a 24VAC power supply is used with lights that are rated for only 12 volts, the lamps will burn out immediately. Always check with the manufacturer of your light fixture to confirm the required voltage.