With the structure standing, the electrical work begins — and this is where a solar system is either made safe or quietly made dangerous. Cable sizing, protections and earthing are invisible once the job is finished, which is exactly why they get cut.
Installation
Solar Electrical Work and Commissioning Tests
Power path
From panel DC to the load, and what protects each stage
Array
Strings wired to matched voltage
DC
DC protection
Isolator, fuses, surge arrestor
DC
Inverter
DC converted to usable AC
DC → AC
AC protection
Breaker, RCD, earthing
AC
Distribution board
House or plant load
AC
A battery sits on the DC side of a hybrid inverter; a bidirectional meter sits after the distribution board on grid-tied systems. Both add their own isolation and protection.
Electrical work
The electrical side is the critical part of the installation.
Wiring. Wiring and electrical components connect the panels to the inverter and to the supply. Properly sized and properly installed cable is essential to efficient generation — undersized cable wastes output as heat for the life of the system and is a fire risk at the same time.
Protections and earthing. DC isolation, fuses, surge arrestors, correctly rated AC breakers and a proper earth. This is the part of the bill that is easiest for a cheap quote to omit, and the part you will never see.
Inverter installation. Inverters convert the direct current the panels generate into the alternating current that homes and businesses actually use. Placement matters too: inverters lose life in direct sun and poor ventilation.
Connection to the grid. If the system is designed to export surplus units, a connection to the local utility is established. That step normally needs coordination with the utility company.
Commissioning tests before handover
Nothing is energised until it has been tested.
Commissioning checklist
What gets tested, and what it proves
String voltage and polarityEvery string matches design before it touches the inverter
Insulation resistanceNo cable damage or moisture ingress in the DC runs
Earth continuityFrames, structure and inverter are bonded to a sound earth
Protection operationIsolators, breakers and RCDs trip and isolate as intended
Structural checkRacking and building confirmed able to carry the array
Generation testMeasured output compared against expected for the conditions
HandoverMonitoring set up, customer trained, documentation issued
A structural engineer is involved where the building or the structure warrants it. Generation is compared against expectation for that day's weather, not against nameplate capacity.
In short
Electrical work and commissioning are what separate a system that runs for twenty years from one that fails or burns. Correct cable, real protections, a sound earth, and tests recorded before energising. Our own engineers do this work and stay reachable afterwards — the same people who commissioned your system answer the phone when you call about it.