Auto UPS Wiring for Partial Load – The Rest Load Depends on Main Power

Electrical Technology

Automatic UPS Wiring for Partial Load – Remaining Load Supplied by Main Power

Suppose you have two light bulbs, one ceiling fan, and a 2 or 3-pin socket in the first room, and one light bulb, two ceiling fans, and a 3-pin 2-gang socket outlet in another room. In a second scenario, you may have all the above-mentioned electrical appliances either in a single room or distributed across different rooms, as shown in Figure 1.

Now, the electrical wiring needs to be arranged in such a way that two light bulbs, one ceiling fan, and a 2-pin socket are powered by the UPS/Inverter (using backup power stored in the batteries) without interruption during a power failure.

The remaining load will continue to rely on the main utility supply or an alternate source such as a generator or wind power. This arrangement is especially useful in cases where uninterrupted power is required for critical equipment such as a personal computer or project work.

In the following UPS/Inverter wiring diagram, it is clearly shown that when the utility power is unavailable, the connected ceiling fan, two light bulbs, and a 2-pin socket operate through the batteries and UPS. This is because the UPS output Live (Phase) wire is connected only to these appliances, while the rest remain off during a power outage.

When the main utility power is restored, all appliances and devices in the wiring system (such as refrigerator, TV, computer, fans, lights, washing machine, etc.) resume normal operation as they are supplied directly by the main source. At the same time, the inverter also recharges the batteries from the utility supply.

Keep in mind that in this wiring method, only the Live (Phase) output from the UPS is connected to the selected appliances that require continuous power, since the Neutral wire is already common and connected to all sockets and appliances in the system.

However, you may also connect both Line (Live) and Neutral from the UPS to the backup appliances if required, as discussed in our earlier UPS/Inverter wiring diagrams.

Click image or open in a new tab to enlarge

Automatic UPS / Inverter Wiring Diagram in Case of some items depends on UPS and the rest on Main or Generator Power
Automatic UPS wiring for partial load & The rest depends on utility Power

Wiring Color Code:

We have used Red for Live or Phase , Black for Neutral and Green for Earth Wire in single phase. You may use the specific area codes i.e. IEC – International Electrotechnical Commission (UK, EU etc) or NEC (National Electrical Code [US & Canada] where;

NEC:

Single Phase 120V AC:

Black = Phase or Line, White = Neutral and Green/Yellow = EGC Grounding conductor

IEC:

Single Phase 230V AC:

Brown = Phase or Line, Blue = Neutral and Green = Earth Conductor.

Good to Know: For safety, use a proper wire size of 6 AWG (16mm2 or 7/064″) conductors when connecting the suitable sized inverter / UPS to the main 120V/240V panel board or 230V consumer unit.

General Precautions

You can find more step-by-step tutorials about UPS/Inverter wiring diagrams and connections, along with detailed descriptions and operating instructions. If you are still experiencing difficulties, feel free to leave a comment in the box below.

Resources and Related Electrical Wiring Installation Tutorials.

Related Articles
↑
Exit mobile version