Lamp life is rated in hours of operation. If lamps are rated for 4000 hours at 12 volts it means that at 4000 hours, 50% of the lamps are still working and 50% are not.

• For maximum light output, tune lighting circuits to provide between 11.5 and 12.0 volts as measured at lamp terminals when all of the lamps on the circuit are operating.
• For longer lamp life, adjust voltage down so lamps receive between 10.5 and 11.5 volts at the lamp terminals.
• Adjusting circuit load/run by using MultiTap Transformers can regulate voltage.
• To determine circuit voltage, use a Volt Meter
• For more information on voltage loading and run length see our Wire Guide.
  

Volts at Lamp	Lamp Life of Rated	Lumen Output of Rated
13v*	60%	340%
12.5v*	75%	175%
12v	100%	100%
11.5v	200%	80%
11v	300%	75%
10.5v	500%	65%
10v	900%	50%
* All low voltage lamps / fixtures are designed to operate at or below 12 volts. Exceeding 12 volts will cause short lamp life and overheating creating possible fixture failure.