Introduction
Adding a new circuit can be a daunting and even dangerous job. We show you how to do it with step-by-step instructions and life-saving safety tips.Circuit Breaker Installation: Know What You’re Getting Into
We believe in safe DIY. That’s why we’ve always been reluctant to show readers how to open a breaker box and connect a new circuit breaker. Even with the power shut off, there’s a chance you could touch the wrong parts and die. But then we figured if we didn’t show you, you’d just go search it somewhere else. And that scared us even more. So we’re going to walk you through the process, showing you the safest way to open the breaker box, wire a new breaker, and test your work.
You might be wondering why you’d even want to try to take on such a dangerous task as circuit breaker installation. There are a couple of situations where connecting a new circuit is beneficial or even necessary. First, the old one may have worn out. While they last a long time, these parts don’t last forever. If the circuit looks or smells burned, it needs to be replaced.
The other reason you might need to connect a new circuit has to do with the electrical load on the house. Certain appliances draw enough power that they need their own load, and the rest of the load is determined by how many things are being plugged in and operated. If you’ve remodeled and added a room to your house, or if you’ve added something big like AC or a hot tub, you may need to add a circuit.
Opening the main electrical panel, also known as the breaker box, and adding a circuit is actually pretty easy. You only have to connect three wires to add a circuit, and each circuit wire is color-coded. But there are some safety precautions, and if you ignore them, you could kill yourself. Really. If you follow our safety steps in order and to the letter, you’ll be fine. But if at any point you’re unsure how to proceed or feel uncomfortable with the project, call an electrician.
Stay away from the large wires and lugs. They’re always live, even with the main breaker (service disconnect) shut off. If you touch them, you could die. Cover the live areas with a cardboard shield to prevent accidental contact while adding a circuit. If you have any doubts about which areas stay live, contact an electrician.
When to call a pro
It’s perfectly okay to leave circuit breaker installation to the professionals if you’re not comfortable doing your own electrical work. It all boils down to your comfort level working with electricity. If you follow these steps and take the safety precautions outlined here, you can do this. But if you open the panel and have second thoughts, reach out to a professional electrician to get an estimate and discuss next steps.
Parts and tools for adding a new circuit breaker
Before you go shopping, open the door of your breaker box and copy the manufacturer’s name, the box model number, and the style numbers of the breakers that are approved for your box. Then buy one of those breakers. If your home center doesn’t sell the right model or brand, you’ll have to go to an electrical supplier. You cannot install a circuit breaker style that isn’t specifically approved for use in your box — even if it fits inside the box.
While at the store, pick up a few 1/2-inch plastic snap-in cable clamps to secure the new cable. They’re safer than metal clamps because you don’t put your hand in the panel to install them. And if you have a second, make sure to brush on the electrical code. This is for your own safety; you don’t want to commit any violations.
You have to shut off the power to your whole house, so you’ll need a powerful work light. An LED headlamp is also a great idea so you won’t have to juggle a flashlight, wire strippers and a screwdriver. Round up a utility knife, wire strippers, electrical tape, a circuit tester (not a voltage sniffer), and a flat-blade screwdriver or No. 2 square-drive tip for your multi-bit driver. If you’ve got those tools on hand, you’re ready to begin.
An Inside Look at Your Breaker Box
Your main breaker box, or electrical panel, might not be exactly like the one here. With any panel, find the large cables and the lugs they’re connected to. They’re the parts that are always live, even when the main breakers are switched off. Here’s how to know what’s what:
- A: Main lugs. They’re always live — even when the main breaker is off. NEVER TOUCH THEM.
- B: Main cables. The black ones are always live. And although they’re insulated, avoid touching them.
- C: Main breaker. Always switch it off before removing the panel’s cover.
- D: Breaker. The hot wire (usually red or black) from each circuit connects to a breaker. If you’re installing an AFCI breaker (as shown on the following pages), you’ll also connect the neutral wire to the breaker.
- E: Breaker bus. Distributes power from the main breaker to the individual circuit breakers. Each breaker snaps onto the bus.
- F: Neutral bus. All ground and neutral (white) wires connect here. If you’re installing a standard breaker, the neutral (white) wire connects here, too. If you’re installing an arc-fault circuit interrupter (AFCI) breaker, you’ll connect the neutral to the breaker and run a “pigtail” wire to the neutral bus.
- G: Breaker space. This panel has room for three more breakers. You can install your new breaker in any open space.
Your Main Breaker Panel Might Look Like This
The photo shows a different configuration where the large cables and lugs are located on the right-hand side of the circuit breaker box, rather than at the center. Take some time to familiarize yourself with these images and then compare them to your box before you attempt to do any circuit breaker installation.
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