Article Summary:
This guide will help you quickly identify if you have a 1st or 2nd generation Nest Protect, and if it’s battery powered or wired. All generations and types of Nest Protect are compatible and can interconnect with each other.

There are several ways to tell which type of Nest Protect you have. The table below summarizes what to look for if you're trying to figure out if you have a 1st or 2nd gen Nest Protect. If you need to determine if you have a battery powered or wired model, click the link below to skip to that section.

How to tell if you have a battery-powered or wired Nest Protect

Look at the design differences without taking your Nest Protect off the ceiling or wall. The most obvious physical difference is the rounded profile of the 2nd gen Nest Protect compared to the square profile of the 1st gen.

If you take your Nest Protect off the ceiling or wall, you can immediately tell by the backplate design: square for 1st gen, round for 2nd gen.

2nd gen Nest Protects also have a battery compartment door, while 1st gens do not.

1) Select the Nest Protect icon.
2) Tap the Settings icon (shaped like a gear) in the top right corner.
3) Select the Nest Protect that you want to check.
4) Select Technical Info.

1st gen

2nd gen

Look at the side

Straight edges

Rounded edges

Look at the backplate

Square

Round

Look at the back

No battery door

Battery door

Serial number (on the back label)

Serial #: 05A or 05C

Serial #: 06A or 06C

Look in the Nest app

Model: Topaz 1.x

Model: Topaz 2.x

How to tell if you have a battery-powered or wired Nest Protect

Look at the front

You don't need to take your Nest Protect off the ceiling or wall to tell if you have a battery powered or wired version. If you see a green light, you have a wired Protect. All wired Nest Protects (120V and 230V, 1st and 2nd gen) have a green power light on the front, just above the Nest logo. Battery powered Protects don't have this green light.

Note: The green light will turn off if there's a wiring problem, if there's a power outage in your home or neighborhood, or if power is switched off at the breaker or fuse box.

Look at the back

If you haven't installed a Nest Protect yet, you can easily tell whether it's a 120V or 230V, or battery powered model, by looking at the back. Wired 120V and 230V Nest Protects will have a power connector.