Isolator and AC Disconnect Switches: Safety and Function
An isolator switch is literally the “safety valve” of a solar system. Its primary role is to isolate a circuit: it disconnects the power supply to a system or component for maintenance or safety purposes.
In other words, what does an isolator switch do? It provides a visible air gap – a complete physical break in the circuit – so technicians know the circuit is completely off.
Unlike automatic breakers, isolator switches are manually operated (by flipping a lever) and ensure there is no voltage in the lines during servicing. As one guide explains, isolators “work by physically separating sections of a circuit – this is called an air break,” protecting people and preventing short circuits.
Because of this, an isolator is essential for any solar+battery setup. “Why do you need an isolator?” Simply put, to protect electricians and equipment. An isolator prevents electric shock by ensuring no current can flow during maintenance, and it allows owners to cut off their home’s power instantly in emergencies.
In solar installations, GRL’s DC isolator switches are used on the PV (panel) side, and AC isolator/disconnect switches are used on the inverter or grid side. Both achieve the same purpose: safe, complete disconnection. For example, GRL notes that in rooftop PV systems, isolators let technicians “de-energize panels before servicing, reducing risks of electric shock or fire”.
GRL’s isolator switches are built to high standards – often rated for 690 VAC (AC side) or up to 1,500 VDC (DC side) – and come in 1-pole to 4-pole configurations. They meet IEC and UL safety standards for solar use. By installing a GRL AC disconnect switch on the distribution box, a home can instantly cut off its inverter from the utility. On the DC side, GRL’s isolator fuse switches on PV combiner boxes or battery panels, allowing each string or battery module to be isolated. This comprehensive isolation ensures seamless and stable power: faults can be contained to one section, and the rest of the system keeps running.
PV Combiner Boxes: Centralizing Solar Arrays
A PV combiner box combines multiple solar panel strings into a single enclosure. Each solar string’s output feeds into the combiner box, which often includes DC isolator switches, fuses (or breakers), and surge protection devices. By consolidating the wiring, a combiner box like GRL’s makes system design cleaner and safer. If a panel string needs service, its line can be isolated at the combiner box with a simple switch, without shutting down the entire array. In practice, these combiner boxes dramatically improve system reliability and modularity: adding more panels is as simple as adding another fuse and switch inside the box. For South African projects, using a high-quality combiner box is standard – one local case study explicitly noted the use of a “PV panel combiner box” along with an AC distribution box and DC isolators. GRL’s combiner boxes are built tough (often IP65/IP66 rated) for outdoor conditions, ensuring that even during dust storms or rain, the array remains protected and uninterrupted.
All‑in‑One Storage Control Unit: Integration at Its Best
