The Neutral Wire Guide
Let's hear from an expert
If you're just starting into building your smart home, especially smart lighting, you probably find yourself wondering what a neutral wire is and what if your house doesn't have one. We had expert Steve Lee back with us to answer the most common questions you may have about neutral wire.
What Is a Neutral Wire?
Since most Insteon-compatible wall switches and dimmers require a neutral wire connection to operate, you need to know if you have one of these in place. A neutral wire is a type of wire in which carries currents back to the source of power and or regular voltage. Essentially, it allows power to return to its original source. We will discuss the purpose of the neutral wire a bit later.
Why is this so important, though?
It’s not just Insteon switches and dimmers but most smart lighting in general that call for this neutral wire.
There are a few hardwired automated switches that don't need a neutral wire, but these are in the minority. Also, you'll be limited to incandescent lights.
Insteon is one of the few companies who have the solution to your problem.
Think do you want to use LEDs or another energy-efficient lighting? If you don't want to be stuck into a small segment of the smart lighting market, you'll need to resolve the neutral wire issue.
Insteon Remote Control Dimmer Switch
Neutral Wire FAQs
The standard electrical system in US home uses AC or alternating current.
With a regular 120-volt AC circuit, the neutral wire provides a return path to earth ground. If the neutral wire disconnects, it would stop the flow of the electricity and break the circuit.
The role of the neutral wire is to provide this path to the electrical panel to complete the circuit. The neutral wire is bonded to the earth ground inside the panel.
This neutral wire is insulated since it forms part of the electrical current circuit. The ground wire, by contrast, is sometimes not insulated since it’s not part of the circuit current flow.
In the bigger picture, the neutral wire forms part of the grounded electrode conductor (GEC). The connection of the neutral wire and ground system occurs only at the electrical panel. This is where the bond to the ground wire is made.
Smart switches need to stay powered up all the time, which is why the neutral wire is critical.
The neutral wire allows the completion of the circuit and the switch to have power even when it's turned to the off position when you want the lights off.
Without this neutral wire in place, the circuit is broken any time the switch is now in the off position. It remains has power when the switch is in the On Mode.
Why is this?
The circuit’s neutral wire is in the junction box holding the light fixture. The two wires that come down to the switch from the hot leg powering the light itself.
For smart switches that function without a neutral wire, a home hub is essential. The bridge is needed because the programming of your login and wireless network details are stored within the hub rather than on a micro controller inside the smart switch.
For this purpose, Insteon makes a highly effective solution with the home hub cheaper than most of the competition. We’ll explore this option below but how can you tell if your home has a neutral wire?
All houses have a neutral wire, so the better question is, "Do I have neutrals in my switch boxes?"
When you're renting a property, you should contact your landlord before updating your locks. Get permission in writing to protect yourself when it comes time to move out.
To answer this question, here are some guidelines:
- If your house was built anywhere from the mid-1980s onward, there’s a strong chance you’ll have neutrals throughout your home
- If you have an outlet on the wall near the switch, the switch box almost certainly contains a neutral
- If they are gang switches, then there's a much higher likelihood of having neutral wires.
If you’re still in any element of doubt, it’s time for further investigation…
Checking The Switch Box
Before you check in your switch box for neutrals, you need to observe all sensible safety precautions before touching any electrical wiring.
- Turn your breaker box off
- Remove the trim plate covering the switch
- Take out the screws from the switch
- Pull out the existing switch so you can examine the wires
- A white wire or group of white wires mean there’s a strong chance the box contains neutrals
At this point, you need to make sure the wire is neutral. The only way to do this is by checking the voltage (110V/120V) between the white wire and the hot wire in the box. The hot wire is normally black. In a standard switch or dimmer, the hot wire is using one of the 2 wires connected to the switch.
This is not acceptable in terms of either building codes or electrical codes.
While the ground wire and neutral wires might connect to the same place in your circuit panel, do not try to cut corners by using this approach.
We'll look now at how to overcome the issue of no neutrals with a couple of approaches.
What To Do If You Don’t Have a Neutral Wire
What do you do, then, if you want more energy-efficient lighting?
You've got three main choices:
1) Run a Neutral Wire
Call in an electrician and get him to run a neutral wire running from the light fixture to the switch.
You could also ask the electrician to rewire both the switch and light fixture, but this is more complex and therefore costlier.
Regardless of the option you choose, running a new wire inside your walls and ceilings might prove too much trouble so you could always opt for smart lighting that doesn’t demand a neutral wire. As we mentioned, though, your options will be more limited.
2) Use Smart Switches That Don’t Need a Neutral Wire
Some dimmable smart switches can be fitted with no neutral wire.
What’s crucial here is the dimming functionality. This reduces the flow of power from your light to your switch to a trickle. While this power will not be sufficient to activate the bulb, it will ensure the switch continues to communicate with the home hub.
Note: Make certain the dimmable smart switch you're looking at will work with the smart bulbs you have in mind. Unfortunately, much only work with older incandescent bulbs.
With any incandescent applications, the Insteon 2-Wire Dimmer Switch is an exact fit. It will only work with incandescent lighting, though.
Here are two solid choices that work with more contemporary, energy-efficient bulbs...
Lutron Caseta Wireless In-Wall Dimmer, White
Lutron Caseta Wireless Dimmer for LEDs
The Lutron Caseta is the connoisseur’s choice. Installation takes just 15 minutes, and you won't need a neutral wire at all.
You will need the Caseta Smart Bridge, but this allows for control in-app on your smartphone along with wide-reaching home automation with a range of compatible devices from Honeywell and Nest to ecobee and the SmartThings ecosystem.
You can use either 150-watt dimmable LEDs or 600-watt incandescent or halogen bulbs.
GE Z-Wave Plus Wireless In-Wall On/Off Smart Switch
Wirelessly schedule and control any hardwired light source, (requires a Z-Wave certified gateway
The Z-Wave-enabled GE does require a neutral wire either.
Max Load: 960W Incandescent, 1/2 HP Motor, 1800W (15A) Resistive
The Z-Wave Plus Smart Switch provides ultimate flexibility for your home lighting by creating custom scenes and scheduling timed events when you're either home or away.
3) Use Dimmable Smart Bulbs
If the idea of replacing switches or rewiring doesn’t appeal or falls outside your budget, you could consider using dimmable smart bulbs instead.
Smart bulbs might not prove the most cost-effective whole-house solution but, depending on your intended use, this is a viable workaround.
With the LIFX LED Bulbs, you leave your wall switch set to on and then take charge of the lighting remotely.
Some bulbs may require a hub or bridge, but you you'll be able to quickly install and take control right away in-app on your smartphone. With an Echo device or Google Home smart speaker, you can also use voice command with Alexa or Google Assistant, respectively.
Get an Expert
If you're in any doubt at all or you're not entirely comfortable working with electrics, hire a professional.
An electrician can quickly, easily, and safely determine if you have neutral wires in your switch box. If necessary, they can also pull neutral wires wherever you happen to need them.