DC isolator
What is a DC isolator?
A DC isolator (DC disconnect switch) opens and closes the DC line between a solar panel string and the inverter on both the positive and negative poles together. It is designed to extinguish the arc that forms with direct current.
Where is a DC isolator used?
It is used in solar PV systems before the inverter's DC input, in battery systems and on DC distribution lines. It allows the panels to be safely disconnected from the inverter for maintenance, faults and emergencies.
Types and selection
DC isolators are chosen by voltage (600 V, 1000 V, 1500 V DC), current and number of poles. There are panel-mounted and enclosed outdoor types, and multi-pole models that disconnect several strings.
What to watch out for
Switches made for AC must not be used on DC lines; a DC arc cannot be extinguished and can cause a fire. The isolator's voltage rating must be higher than the string's open-circuit voltage in the coldest weather. Pole connections (+ and −) follow the manufacturer's diagram.
Terminals
DC isolator
- Panel side
- 1, 3
- Inverter side
- 2, 4
Try it in the simulator.
This component is in CoilPath with its real look. Add it to a circuit, wire it and see how it behaves in the simulation.