Understanding your power supply dictates exactly what equipment you can install, from solar arrays to fast EV chargers.
l Single Phase: Standard for approx. 90% of residential homes. It flows like a single alternating wave.
l 3 Phase: Standard for commercial buildings and large luxury homes. It flows like three overlapping waves, providing constant, heavy-duty power.
The Visual Inspection (Main Breaker Panel)
The easiest way to begin identification is by opening your main breaker panel (switchboard). Locate the Main Switch, which is typically the largest switch in the panel.
The "Main Switch" Test
Locate the Main Switch (usually the largest switch at the top or bottom of the panel).
Single Phase (Residential) | 3 Phase (Commercial/Large Home) | |
Breaker Width | Single Pole (Standard width) or 2-Pole (Double width) | 3-Pole (Very wide, takes up 3 slots) |
Incoming Wires | 2 Wires: 1 Hot (Live) + 1 Neutral | 4 Wires: 3 Hots (Live) + 1 Neutral |
Service Fuse | Typically 1 Service Fuse on the utility side | Typically 3 Service Fuses on the utility side |
Note: While visual cues like three joined switches are a strong indicator of a 3-phase supply, they are not definitive. In some regions, single-phase 380V configurations exist, which can lead to visual misidentification. Always use a multimeter to measure the actual voltage to ensure accuracy before purchasing or installing equipment.
