How Backup Power Systems Operate

Various natural disasters can lead to prolonged power outages. Events like tornadoes, hurricanes, flooding, lightning strikes, ice storms, and blizzards can disrupt electricity for hours or even days. Even a simple issue, such as a blown transformer or a car hitting a utility pole, can result in a power outage for an entire neighborhood lasting one or two days.

Electricity is something we all rely on, so a power outage lasting more than a few minutes can quickly become frustrating. When the power goes out for an extended period, it can lead to significant issues that may be costly or dangerous.

• During winter, a power failure often shuts down your home's heating system. As temperatures drop, depending on your location, your home may become uninhabitable. Additionally, frozen pipes could cause substantial damage, potentially costing thousands of dollars.
• A power outage also affects refrigerators and freezers. In summer, frozen food will melt, creating a mess. If you've invested in bulk meat, like a side of beef, you could lose over $1,000 in the event of a multi-day power failure.
• If you require medical equipment powered by electricity, a power failure could put your health in jeopardy.
• In rural areas with private wells, a power failure can also cut off your water supply.

Fortunately, it's now easier than ever to purchase an emergency power system that can prevent these problems. In this article, we'll explore a range of options and discuss various ways to integrate them into your home, ensuring that you never have to worry about a power failure again.

Power Backup Solutions and Objectives

• You can purchase a generator powered by an engine. This engine can run on gasoline, diesel, or propane.
• An alternative is to buy an inverter, which you can power using your car's battery or a dedicated deep-cycle battery designed for the inverter.

• I only need a basic set of comforts – I want to power a few lights to avoid using candles, charge my cell phone, run an emergency radio, and operate a fan. A small generator or a compact inverter plugged into your car’s lighter socket can meet these needs.

• I want to power a microwave, TV, lights, and my computer to cook and get some work done. A 1,000-watt generator with extension cords will provide the necessary power for these devices.

• My main objective is to keep my refrigerator and freezer running, but I also want to power lights and small appliances. A 2,500- to 3,500-watt generator with extension cords can handle this.

• I want to power my well pump, water heater, furnace blower, a room air conditioner, refrigerator, and other essential household appliances. A 5,000-watt generator connected directly to your home's electrical panel can accomplish this.

In the following section, we will explore how to better understand your power requirements.

Assessing Your Power Requirements

Power is commonly measured in watts, and for an emergency power source, there are two important wattage ratings to consider: steady-state wattage and surge wattage. For example, a typical 60-watt incandescent light bulb draws 60 watts both when it is first turned on and while it remains on. In contrast, a ceiling fan motor may require 150 watts to start but only 75 watts to keep running. The additional power needed for startup is called surge wattage, which is common in any device with an electric motor. Below are the typical wattage requirements of some household devices:

As seen in the chart, a whole-house heat pump or air conditioner consumes a significant amount of power. If your home relies on a heat pump and you need to maintain warmth during a winter power outage, you will either need a very large generator, which can be quite expensive, or an alternative heat source like wood or propane.

If you plan to use sensitive devices such as TVs and computers with your emergency power system, it's essential to have proper surge protection. Additionally, for computers, an uninterruptible power supply (UPS) is necessary. When larger appliances like refrigerators start, even a small generator may struggle to provide stable power due to the surge. A UPS ensures your computer remains protected from sudden power disruptions.

To determine your power needs, calculate the combined normal and surge wattages for all the devices you want to run simultaneously. Here are two examples of how to do this:

1. If you plan to run a small TV and two 60-watt light bulbs, your emergency power system should have a continuous capacity of at least 220 watts and a surge capacity of 270 watts. Rounding up, you’ll need a system capable of 250 watts continuous and 300 watts surge.
2. If you need to run a refrigerator, color TV, and microwave at the same time, you’ll need 2,250 watts of continuous power and 3,800 watts of surge power in the worst-case scenario (if all three devices start at once). However, by managing your usage and ensuring they don’t all turn on simultaneously, your surge requirement drops to 2,400 watts. If you prefer to run only one device at a time, sizing your power system based on the refrigerator’s requirements will suffice, as it’s the largest power consumer.

Choosing Between an Inverter and a Generator

The drawbacks of engine-powered generators include:

• Fuel storage
• Noise (especially the more affordable models)
• Engine upkeep

At the Brain residence, we use a 5,000-watt generator. This allows us to power nearly everything in the house, including the well pump, water heater, and refrigerator. The only limitation is that we cannot use the heat pump, so we have gas logs as a backup heat source. We do manage our power usage by staggering it, but it's not a major inconvenience for us. For example, we run the refrigerator for an hour, then turn it off to power the well pump.

An inverter is an electrical device that changes 12-volt power into 120-volt power. Typically, you would use an inverter connected to your car’s battery or a deep-cycle battery specifically bought to power the inverter. For power needs in the 200-watt range, an inverter is a simple and affordable solution. If you want to scale up to around 2,500 watts, inverters can still be useful, but they tend to become costly (a 2,500-watt inverter could cost $600 to $1,000, plus the price of deep-cycle batteries and a charging system). Inverters offer two primary benefits:

• They operate quietly
• They require no maintenance (when powered from your car's battery -- if you set up a deep-cycle battery bank, you will need to maintain the batteries).

(It's worth noting that a large battery bank connected to an inverter plays a crucial role in most home-scale solar power systems. These systems use solar panels to recharge the batteries. For more details, see How Solar Cells Work.)

In our household, we use a 140-watt inverter. During the day, we run the generator, and at night, we hook the inverter to the car to power a couple of compact fluorescent bulbs that illuminate our house.

Connecting the Power to Your Home

• You can use extension cords to connect the generator to specific appliances.
• An electrician can wire the generator directly into your home's circuit panel, allowing you to switch the entire house over to generator power.

To switch your home to generator power, follow these steps:

1. I ground the generator.
2. I start the generator and allow it to run for five minutes to stabilize.
3. I connect the generator to the circuit panel.
4. I activate the generator's circuit breaker. (The electrician will install an interlock system to ensure that the panel's main breaker automatically shuts off when the generator's breaker is engaged, preventing the generator's power from escaping your home. For more details on this wiring, see Installing a Backup Generator.)

Three important points from the previous section:

1. It is essential to have a licensed electrician install the generator for you. A basic system installation will typically cost between $200 and $400.
2. Ensure that your generator is properly grounded according to the owner's manual. You can connect its grounding to your home's existing grounding rod or purchase an 8-foot grounding rod from the hardware store for about $12.
3. Make sure to disconnect your home from the power grid before activating the generator. Failure to do so can result in electrocution hazards for line workers. Additionally, your generator will attempt to power the entire neighborhood, which it obviously cannot do. Having the electrician install a positive interlock system ensures that the house's main breaker shuts off automatically when the generator’s breaker is engaged.