What happens if you wire a smart light switch wrong?

Smart light switches are a great option for making your lights smart. Once your lights are connected to the smart switch, you can control them with your phone or a home assistant device. Depending on the brand and model, you may be able to control the brightness of your lights, turn them on and off by using your voice, and set them to respond to motion in your rooms. Of course, they need to be correctly wired for these functions to be available. 

Wiring a smart light switch wrong can result in the switch not working correctly. If the wiring creates a short circuit, it can lead to damage to the switch and/or a burnt-out fuse. Errors can also lead to electric shock, fire, and a violation of local wiring codes. However, errors can be avoided. 

Smart light switches (well, most of them) have been designed to be easily installed by homeowners. However, if you are not familiar with the normal wiring of a switch, you may find the task rather daunting. After all, smart switches are expensive. You don’t want to make a mistake in the wiring that costs you your switch! 

Before you start with the installation, you may want to know what exactly could go wrong. What would the consequences of an error in wiring be, and is it worth the risk of installing the switch yourself rather than paying an electrician to do it for you? You’ll find the answers to your questions below. 

What can happen when you wire a smart light switch wrong?

The switch may not work. If you do not connect the switch to the neutral wire, the switch will not have a power supply. It would thus not be able to listen for a command of turning on or off. In the case of a motion sensor light, it would not respond to movement. 

If the switch is part of a three-way system (where more than one switch controls the same light, for example), switching the common and traveler wires would result in only one switch working to turn the light on and off. 

Secondly, you could shock yourself. If you connect the hot wire to a ground screw without a functioning ground wire, you can shock yourself. 

If you damage the wires during installation, you could break the switch, or the wires could come loose. Loose wires present a danger when changing the light switch. 

Thirdly, you could create a short circuit in the switch. A short circuit can cause the breaker or fuse to pop. If the fuse does not burn out, the wires in the device may melt. This would damage the smart switch, most probably irreparably. 

If the wires in the circuit became hot enough, the resulting resistance could even cause a fire.

Fourth, incorrect wiring could violate local wiring codes. DIY homeowners often make the mistake of connecting multiple wires to a single terminal on a receptacle or switch, for example. A building inspector would fail this. This could lead to potential problems when trying to sell or rent out your house. 

Electrical hazards cause more than 300 deaths each year in the U.S. workforce.

When do smart light switches work?

Smart light switches work when they have been correctly wired to the lights that they control. Both the light and the switch itself require power. In the case of a single smart switch, the switch must be correctly connected to the lights via the hot wire and to the power source via the neutral wire.  

Connecting the switch to the neutral wire may be done using a small additional wire (which is usually included in the box with the smart switch) to create a pigtail connection. The short additional wire is stripped off at each end to tie one end under the wire nut together with the other neutral wires and the other end to the terminal screw on the switch itself. 

In the case of a three-way switch, more than one switch may control the same light. In addition to the connections required for a single switch, the system also requires a traveler wire (which is usually red) that connects one switch to the next. 

Take note that in a three-way system only one switch is connected to the lights. The second switch can send a signal to the first to turn it on or off and does not need to communicate with the lights directly. 

Tips for wiring a smart light switch

  1. Always make sure that the power is switched off at the breaker before removing the cover plate of the switch. 

If you aren’t sure which switch on your breaker controls the wires in the switch, you can use a voltage tester to check which wire is on. Of course, you would need to remove the cover plate for this. Proceed with caution! 

  1. Wear the correct clothing and use the correct equipment

To prevent electric shock, wearing a ground bracelet and shoes with rubber soles is recommended. You should also make sure that the tools you are using have rubber grips.

  1. Understand the wiring of a normal light switch 

I recommend taking some time to understand the wiring of a normal (non-smart) light switch before installing a smart light switch. This will make it much easier to figure out the different wires. 

The YouTube video below explains the wiring of a normal light switch very well: 

  1. Make use of the user manual

If you’re like me, you probably avoid reading user manuals at all costs and prefer to figure your appliances out yourself. Although this approach works well for many appliances (I’m sure you can figure out how to switch off a hairdryer on your own), I recommend making use of the user manual of your smart switch. 

Most manuals include detailed instructions with images of how the switch should be installed. Sometimes these instructions can become overwhelming, which is why point number 2 above is important. 

  1. Wrap your smart switch in electrical insulation tape 

Most people will hold on to the sides of a smart switch when removing it from the wall box. Unfortunately, most smart switches also have their terminal screws on the side. This can lead to short circuits and electric shocks, especially if the wiring was not done correctly.

To avoid this scenario, wrap electrical tape around your smart switch sides to cover the terminal screws once you have connected the wires to them. This will protect anyone touching the sides of the switch in the future. 

  1. Hold onto the top and bottom of the switch when removing it from the wall

Just in case the switch is not wrapped in insulation tape (refer to point number 4), always hold a smart switch at the top and bottom when removing it from the wall socket. 

  1. Mark wires clearly if necessary

If you have an older home, the hot wire may also be white like the neutral wire, rather than black. Once you have figured out which wire is the hot wire, mark it with a strip of black electrical tape to avoid future confusion. 

*We wrote a helpful article on how to install a smart light switch. Feel free to read the article to get some helpful and insightful knowledge.

Which smart light switch is easiest to install? 

The table below some of the top smart light switches (according to Tech Hive and Tom’s Guide), their “easy to install” star rating on Amazon, and some potential installation issues based on customer reviews. 

Smart switch brand and type“Easy to install” star rating on Amazon (out of 5 stars)Potential installation issues
C by GE 4-Wire Smart Motion Sensor Light Switch3.7Does not work with third-party products (all bulbs and other switches connected to this switch must also be C by GE switches)
Lutron Caseta Wireless Smart Lighting Dimmer Switch and Remote Kit4.6Compatibility with certain light bulbs may be compromised – check before you purchase
Enbrighten Zigbee Smart Light Dimmer with QuickFit and SimpleWire (43090)4.0Installation in SmartThings may require you to change the device type to “Zigbee switch” before it will function. You also need to add a skill on the Enbrighten app.
Leviton Decora Z-Wave Plus dimmer (model DZ6HD)3.6You might need to add a neutral wire for the switch.Several people have had trouble connecting the switch to a Leviton appKasa Smart Dimmer Switch HS2204.3The switch is quite large and if you have small light boxes, it might not fitLutron Aurora Smart Bulb Dimmer Switch 4.8If you forget that you have the dimmer switch installed, you may flick it too hard, and it can fall off quite easilyPhilips Hue Smart Dimmer Switch 4.8The switch doesn’t fit over many regular switches, so it needs to be installed next to the existing switch. This is more of an aesthetic issue. 
Ecobee Switch+ Smart Light Switch 4.1The device seems to have quite a bit of connectivity trouble, so it should be installed close to your router. You can also expect to struggle to connect it to your other devices.

Do I have to install my smart light switch myself?  

You do not have to install a smart light switch yourself. In fact, if you purchase the Noon Lighting System smart switch, you may not install it yourself. This system is only available through professional installers. 

You can hire a professional electrician to install a light switch for you. However, this is rather expensive, especially if you have more than switch to install. 

If you are inexperienced with switch wiring, it is recommended that you hire a professional electrician. Perhaps a good option would be to hire an electrician for one switch, watching how it’s done, and then trying it yourself for the next one. 

If you are renting your home and do not want to mess around with the wiring, investigate the option of a smart plug. A smart plug can be inserted into an electrical socket without having to change the wiring. 

We’ve covered an in-depth article on Smart Switches vd Smart Light Bulbs. Have a look!

How Much To Install A Smart Light Switch? Electrician Rates.

According to Fixr, the national average cost for installing a light switch is between $100 and $200. Smart light switches may cost more to install than regular light switches (up to $275) if the installation requires new wiring, connecting the switch to Wi-Fi, and programming different features. 

The cost of the switch is usually included in these rates. Electricians and contractors may add a mark up of up to 15% to the price of switches, so you could save some money by purchasing the switch yourself. 

These prices could be expected under favorable site conditions and should also include planning, acquiring material and equipment, preparing and protecting the area, setup, and cleanup. If conditions are not favorable (for example if there is a water leak in the area or cleanup is required before the installation begins) then the price will be even higher. 

The equipment required for installing a light switch includes connectors, fittings, fasteners, and mounting hardware. 

The cost of installing a light switch may be worth it if you only want to install a single light switch. However, if you need multiple switches installed, it might well be worth it to learn to install them yourself. 

Remember that electricians may also charge for travel costs. If you do have multiple switches to be installed, try to arrange for them to all be installed on the same day to save on travel expenses. 

How Much Are Smart Light Switches?

The cost of a smart light switch varies depending on its features. The table below shows the cost of some of the top smart light switches (according to Tech Hive and Tom’s Guide).

Home Streamliner’s Take: 

Since wiring a smart light switch can be a challenging and even dangerous task if you have never done it before, I recommend hiring an electrician once off to install a switch for you. This allows you to see how it should be done so you can avoid wiring your switches incorrectly. 

After that, installing additional switches yourself will save you a considerable amount of money and, in my opinion, is well worth the effort. 


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What Happens If You Wire A Smart Light Switch Wrong
What Happens If You Wire A Smart Light Switch Wrong? 2
HomeStreamliner
HomeStreamliner

This blog aims to share my research and first-hand knowledge in a helpful way. My goal is for you to be able to save time and find happiness in a streamlined home.