Did electrical for 6.5kW solar system in Fendalton where couple wanted to cut their power bills and be more sustainable. Solar company handled panels and roof work but we did all the electrical connection. Installed inverter in garage, ran DC cables from panels to inverter, wired AC connection from inverter to switchboard, installed isolators for safety, set up monitoring system, and coordinated grid connection with power company. After inspection and approval their system went live. First month they exported more power than they used. Power bill went from $280 per month to like $40. They were stoked with the savings and liked watching their generation on the app.
Solar electrical work is specialized part of solar installation. Panels on roof are one thing but getting power safely into your house and connected to grid needs proper electrical work. High DC voltages from panels require careful handling and specific safety devices.
How Solar Systems Work
Understanding solar helps make sense of the electrical work.
Solar panels generate DC power from sunlight. Each panel maybe 300-400 watts. String of panels wired together produces high DC voltage - maybe 300-600 volts depending on configuration.
Inverter converts DC to AC power. Takes high voltage DC from panels and converts to 230V AC that your house uses. Modern inverters are smart - they optimize power production and monitor system performance.
AC power feeds into your switchboard. From there it powers your house first. Any excess power exports to grid.
Grid connection lets you export surplus. Power company credits you for exported power. When panels arent producing enough you draw from grid like normal. Net metering means you only pay for net power used.
Batteries are optional addition. Store excess solar power for use at night. More complex electrically cause batteries operate at different voltages and need special equipment.
Electrical Components of Solar System
Solar systems have several key electrical components.
Inverter is the main component. Converts DC from panels to usable AC. Mounted indoors or in weatherproof enclosure. Sizes range from 3kW to 10kW+ for residential. Must match panel array size.
DC isolator at inverter location. Lets you shut off DC power from panels. Required for safety so you can work on system without high voltage present.
AC isolator between inverter and switchboard. Shuts off AC side of system. Required by regulations and for safety.
Junction boxes on roof. Where panel strings connect together before running to inverter. Weatherproof boxes with proper cable glands.
Metering equipment tracks generation and export. Usually installed near main meter. Records how much power you produce and export.
Monitoring system connects to internet. Lets you see production in real time. Most inverters have wifi built-in and phone apps.
Inverter Installation
Inverter installation is core of solar electrical work.
Location matters for inverter. Usually garage or utility room. Needs to be accessible, protected from weather, not too hot. Close to switchboard reduces AC cable length.
Mounting securely to wall. Inverters are heavy - maybe 20-30kg. Need solid mounting to wall studs or proper backing. Must be level for proper operation.
DC connections from panels. Heavy duty cables run from roof to inverter. Usually through conduit for protection. Proper DC connectors rated for high voltage and outdoor use.
AC connection to switchboard. Dedicated circuit from inverter to main board. Size depends on inverter output - maybe 20 or 32 amp circuit.
Earthing inverter properly. Connected to earthing system. Critical for safety with high DC voltages involved.
Communication cables for monitoring. Network cable or wifi connection so inverter can upload data. Lets you track system performance remotely.
DC Cabling from Panels
DC cabling carries high voltage and needs special handling.
Cable sizing for DC circuits. Larger cable than you might expect cause DC voltage drop is critical. Undersized cable loses power and creates heat. Usually 4mm or 6mm cable for typical residential.
Cable rating for outdoor and UV. DC cables exposed to sun and weather. Must be rated for outdoor use. Special solar cable with UV resistant insulation standard.
Running cables from roof to inverter. Usually through conduit for protection. Path planned to avoid damage and look neat. Sometimes through roof space, sometimes external.
Proper terminations critical. DC connectors must be tight and secure. Poor connection causes arcing and fire risk at high DC voltages.
Separation from other cables. DC cables kept away from other wiring where possible. Reduces interference and keeps things organized.
Safety Isolators
Isolators are mandatory safety devices for solar systems.
DC isolator disconnects panels from inverter. Mounted near inverter usually. Rated for DC voltage and current. Must be accessible and clearly labeled.
AC isolator disconnects inverter from switchboard. Lets you safely shut down AC side of system. Required by regulations.
Lockable isolators preferred. Can be locked off for maintenance. Prevents someone turning system on while youre working on it.
Labels on all isolators. Clear signs showing what they do. Required by code so anyone knows how to shut system down safely.
Emergency shutdown at panels. Some systems require way to shut panels off at roof level. Additional roof isolator in these cases.
Grid Connection and Metering
Connecting solar to grid requires coordination with power company.
Application to power company before installation. Need approval to connect solar. They verify system wont cause grid problems. Usually straightforward but takes few weeks.
Export limiting if required. Some areas have restrictions on how much you can export. Inverter can be configured to limit export to grid. We set this up according to power company requirements.
Meter upgrade sometimes needed. Old meters dont record export properly. Power company installs smart meter that tracks both import and export. They handle meter swap but we coordinate timing.
Anti-islanding protection built into inverter. Prevents system feeding power to grid during outage. Safety feature so line workers dont get electrocuted working on dead lines.
Grid connection point at switchboard. AC connection from inverter lands on dedicated breaker. Wired so solar power feeds into house first before exporting.
Inspection and Approval
Solar installations require inspection before going live.
Electrical inspector checks installation. Verifies wiring meets code, isolators correct, earthing proper, labels in place. We arrange inspection after completion.
Certificate of compliance issued. Documents that electrical work meets code. Required before power company will approve connection.
Power company approval needed. They review paperwork and sometimes inspect. Once approved they enable export metering and system goes live.
Building consent might be required. Depends on system size and local rules. We check requirements for your area.
Testing before inspection. We test all circuits, verify voltages are correct, check safety systems work. Makes sure everything passes inspection first time.
Battery Storage Systems
Adding batteries makes solar system more complex electrically.
Battery types vary. Lithium batteries most common now. Maybe 10-15 kWh capacity for typical home. Some systems use lead-acid batteries but less common.
Battery inverter separate from solar inverter usually. Manages charging and discharging. Some systems use hybrid inverter that handles both solar and battery.
DC coupling vs AC coupling. DC coupled systems connect battery directly to solar DC. AC coupled systems connect after inverters. Different wiring and equipment for each.
Battery location matters. Heavy - maybe 100kg+ for whole system. Needs cool location cause batteries dont like heat. Garage often works if not too hot in summer.
Additional safety equipment. Batteries store lots of energy. Need proper fusing, isolators, emergency shutoff. More complex than solar alone.
Backup power capability. With right equipment batteries can power house during outages. Requires special wiring to separate critical circuits from non-critical.
Working with Solar Companies
Solar installations involve coordination between trades.
Solar company handles panels and racking. They mount panels on roof, install racking, run DC cables on roof. We coordinate timing with them.
We handle everything from roof down. Inverter installation, AC wiring, switchboard connection, isolators, metering. All the electrical work.
Sequencing matters. Usually solar company installs panels first. We come after to do electrical connections. Sometimes we do some prep work first like inverter mounting.
Communication important. We work with solar company on cable routing, isolator locations, system configuration. Prevents problems and delays.
Some solar companies have their own electricians. Others subcontract electrical work. Either way electrical work must be done by licensed electrician and properly certified.
Common Installation Challenges
Solar electrical installations sometimes hit issues.
Switchboard location far from good inverter spot. Long AC cable runs cost more and might need heavier cable. We find best compromise between inverter location and wiring practicality.
Switchboard at capacity. Adding solar requires free breaker slot. If board full might need board upgrade. Adds cost but necessary.
Roof design complicates cable routing. Multiple roof levels, odd layouts, limited access. We figure out practical path for cables.
Power company restrictions. Some areas have limitations on system size or export. We work within these constraints to get you maximum possible system.
Shading on roof affects performance. Not electrical issue but impacts system design. Solar company handles panel placement but affects total power production.
Did house in Riccarton where switchboard was on opposite end of house from best inverter location. Running cable through house would be destructive and expensive. We mounted inverter in garage which meant longer DC run from roof but kept AC wiring simple. Sometimes you gotta compromise.
Monitoring and Performance
Modern systems include monitoring to track performance.
Inverter connects to internet. Usually wifi but can use ethernet. Uploads generation data to monitoring portal.
Phone apps show real-time production. See how much power you're making right now. Track daily, monthly, yearly totals. Compare to previous periods.
Export and import tracking. See how much you export to grid versus import from grid. Helps understand your usage patterns.
Alerts for problems. System notifies you if production drops or inverter goes offline. Lets you catch issues quickly.
Performance comparison. See if your system producing what it should based on weather and season. Identifies problems with panels or equipment.
Maintenance and Troubleshooting
Solar electrical systems need occasional attention.
Annual inspection recommended. Check all connections, verify isolators work, test safety systems. Catch problems before they become serious.
Keep inverter vents clear. Inverters have cooling fans. Dust and debris block airflow causing overheating. Clean vents periodically.
Monitor production regularly. If output drops suddenly might indicate problem. Could be panel shading, equipment failure, or grid issue.
Check isolators operate smoothly. Test them occasionally to make sure they still work. Stuck isolator is safety hazard.
Inverter errors need investigation. Inverters show error codes if problems detected. We diagnose and repair issues.
Most common problems are inverter failures, isolator issues, loose connections. Panels themselves rarely fail but connections can corrode over time.
Cost of Solar Electrical Work
Electrical portion of solar installation is part of total cost.
Standard residential installation runs $1500-2500. Inverter mounting, DC and AC wiring, isolators, switchboard connection, testing, certification. This is electrical portion only - panels and racking separate.
Complex installations cost more. Long cable runs, difficult access, switchboard upgrades, multiple inverters. Maybe $2500-4000 for complicated jobs.
Battery additions run $1500-3000 for electrical work. Battery inverter, additional wiring, safety equipment, integration with existing system.
Repairs and service typically $200-500. Depends on problem. Inverter replacement is major cost but usually covered by warranty.
Total solar system cost including panels, inverter, installation is typically $8000-15000 for residential. Electrical work is roughly 15-20% of total.
Payback period depends on your power use. Average 7-10 years for typical system. After that its free power. Systems last 25+ years so you get many years of benefit.
Choosing System Size
System size affects electrical work and cost.
Small systems maybe 3-4 kW. Good for low power users or limited roof space. Smaller inverter and simpler electrical work.
Medium systems 5-7 kW most common for residential. Covers typical household usage with some export. Balanced cost versus benefit.
Large systems 8-10 kW+ for high power users. Might need larger switchboard capacity. More complex electrical work.
Export limitations affect maximum size. Power companies limit export in some areas. Might restrict system size even if you want bigger.
Future proofing worth considering. If you might get EV or pool heater later get slightly bigger system now. Easier than expanding later.
Three Phase vs Single Phase
Power supply type affects solar installation.
Most houses have single phase. Standard solar inverters designed for single phase. Straightforward installation.
Three phase houses need three phase inverter. Or three small inverters one per phase. Balances load across phases. More complex and expensive.
Export limitations on three phase. Each phase has export limit. Cant export full system capacity if production unbalanced across phases.
Phase balancing important. Try to distribute panels evenly across phases. Keeps system balanced and maximizes export capability.
Future of Solar Technology
Solar technology keeps improving.
Panel efficiency increasing. New panels produce more power in same space. Makes solar viable even with limited roof area.
Battery costs dropping. Home batteries becoming affordable. Eventually might be standard part of solar systems.
Smart inverters with more features. Better monitoring, grid support functions, integration with home systems. Makes solar more useful.
Vehicle to grid coming eventually. Use EV battery to power house or export to grid. Requires special equipment and regulations but promising technology.
Good electrical installation now means ready for future upgrades. Proper wiring and capacity means easier to add batteries or other equipment later.