FCSP Amperage Control

[Tony Burgh]

Inside the charger there are two wires in the charge cable to carry AC to the truck. There are two coils for current measurement. Instead of running each wire through each coil, both wires run through one coil and only one wire through the other.
Why is that?

Sponsored

 

[Maquis]

That’s to measure the current difference between the 2 wires. Normally the difference is zero (same current on both wires). This is used to detect a ground fault. If the currents do not equal, some of it is going on a different path, likely through an unintentional ground path. This is the GFCI function in the EVSE as required per the UL listing standard.

Edit - the above describes the CT with both wires running through it. The one with the single wire is to measure the actual charge current.

 

[Tony Burgh]

Thanks.

Sponsored