Shock Hazard: Unburdened CT's should never be handled with primary current applied!
CT Calculation Helper
Enter the information below to calculate the burden resistor required for Current Transformers that do NOT contain a built-in burden resistor.
Do I need a burden resistor?
Some CT's contain a built-in burden resistor. If the CT is rated in Volts per Amp (for example 0.333V at 100A) then it already contains a built-in burden resistor.
If a CT is rated as a turns ratio, then it likely does NOT contain a burden resistor. The calculator below can be used to determine the desired burden resistor value.
A CT encloses a primary current (Ip) and produces a secondary current (Is) through the seconday winding of N turns (the turns ratio).
The voltage produced across the burden resistor (R) is given by the accompanying equation.
The following calculator can be used to determine a suitable burden resistor for use with the Z3 NetMeter: