Measuring Voltage at the Spider Splice
Voltage loss calculations
We recommend measuring field voltage at the fixture using our MR-16 Voltage Testing Tool (CTESTMR16) and S8 Voltage Testing Tool (CTESTS8) - these tools enable you to test voltages while all system lamps are lit, but they can only be applied to MR-16 and S8 socket types. For other socket types, and when you don't have these tools, voltage can be tested at the Spider Splice.
When measuring voltage at the Spider Splice, keep in mind the voltage loss between the Spider Splice and the lamp. This voltage loss varies according to the lamp wattage, lead length and wire gauge.
After taking the reading at the Spider Splice subtract the following to estimate voltage at the lamp.
Fixtures with 25' #16/2 lead wire: (CMU1CB, CCH1CB, CNO1CB, CBL1CB, CBL5CB, CWLWFLLEAD and CWW1CB)
20W: 0.3v | 35W: 0.6v | 50W: 0.8v
Fixtures with 25' #18/2 lead wire: (CNL1CB, CDL1CB, CDL2CB and CEWL5CB)
10W: 0.3v | 20W: 0.5v
Fixtures with 35' #16/2 lead wire: (CCTL1C, CCH5CB, CMU2CB and CSA1CB)
10W: 0.2v | 20W: 0.5v | 25W: 0.6v| 35W: 0.8v | 50W: 1.2v