Generator and battery backup in the Phoenix Valley

Monsoon season runs from June 15 to September 30, and the storms that come with it bring high winds, microbursts, dust storms and lightning. Those can take down lines and leave neighborhoods without power, sometimes in the hottest stretch of the year.

For many households an outage is an inconvenience. For others it is a real problem. Think about anyone at home who depends on oxygen or other powered medical equipment, older family members who cannot handle the heat, pets, a freezer full of food, a home office, or a well pump.

If someone in your home relies on medical equipment, ask APS or SRP what support they offer customers in that situation, and keep a plan for where to go if the power stays out. Backup power helps a lot, but it should not be your only plan.

There are three common ways to keep power on during an outage, and each one fits a different household.

A standby generator sits outside on a pad, runs on natural gas or propane, and starts on its own when the grid goes down. Sized for it, it can carry a large share of the house, including the AC. A home battery stores power from the grid or from solar and takes over quietly with no fuel to manage. It covers fewer loads for a limited time unless solar can recharge it. A portable generator costs the least up front, but you have to start it by hand, keep it fueled, and connect it through a proper inlet with an interlock or transfer switch.

We help you weigh cost, noise, fuel, run time and what you actually need to keep on, then wire the system you choose.

Plugging a generator into a dryer outlet, or any other outlet, with a homemade double-ended cord is called back-feeding. It is never safe.

Without a transfer switch or interlock, power from your generator can flow out through your meter and onto the utility lines. Transformers can step that voltage up, and a line worker repairing storm damage down the street can be killed by a line they believed was dead. Back-feeding can also overload your house wiring, start a fire, and wreck the generator when grid power comes back.

The fix is simple. A listed interlock or transfer switch makes sure the house is never connected to the grid and the generator at the same time.

Wherever you run a generator, keep it outside and well away from doors, windows and vents. Never run one in a garage, even with the door open, because of carbon monoxide.

Every backup system needs a safe way to move the house from utility power to backup power. For standby generators and many battery systems, that is an automatic transfer switch that senses the outage and changes over on its own. For portable generators, it is usually a manual transfer switch or a listed interlock kit on your main panel, fed from an outdoor inlet box.

Unless the system is sized for the whole house, we usually move the essential circuits to a critical-load subpanel. Common choices are the refrigerator, some lights, a few outlets, the internet equipment, the garage door opener, a well pump and any medical devices. Everything else stays on the main panel and waits for the grid.

With a portable generator and an interlock, you choose which breakers to turn on and keep the total under what the generator can supply. We label the panel so that is easy to do with a flashlight.

In much of the country, backup power means lights and a fridge. In Phoenix in July, people want the air conditioning, and that changes the size of the system.

A central AC compressor draws a large rush of current when it starts. Keeping it running takes a standby generator sized for it, or a battery system with enough output and storage. A soft-start device on the compressor can sometimes cut that starting load enough to make a smaller system work. Because it goes on the AC unit, we confirm it suits your equipment first.

Heat matters for the backup equipment too. Generators lose some output in very hot weather, and batteries have temperature limits set by the manufacturer. A battery on a west-facing garage wall can run hotter than its label allows. We plan placement with summer temperatures in mind and size systems with some margin.

Many people expect solar to keep the lights on in an outage. A standard grid-tied system does not. It shuts off when the grid goes down so it cannot send power onto lines that crews are working on. To use your solar during an outage, you need a battery and equipment designed to separate your home from the grid.

Solar has to be approved by APS or SRP before it is connected, and adding a battery often means updating that approval. The bus rating and main breaker of your panel limit how much solar can feed into it, and a battery can add to that calculation.

We work alongside your solar company on the electrical side: panel upgrades, backup subpanels, main breaker changes and the wiring between your panel and the battery equipment. If your panel is too small, or it is a Federal Pacific or Zinsco, we will tell you before the battery goes in.

Start in winter or early spring. Standby generators and batteries can take time to source, permit and install, and you want the system in place before June 15, ahead of the first outage.

If you already own a portable generator, an interlock or transfer switch is a smaller job, but it still needs to be done before the storms. And if you are upgrading your panel now, it is smart to plan the space and wiring for a battery, even if the battery comes later.