Do Smart Switches Need A Ground? What Happens If You Don’t Ground The Switch?


Tp-Link Smart Switch Back Wiring

Smart switches are beginning to replace older light switches in many homes. I’ve already replaced several in my own house. If you have an older house that doesn’t have a ground, you are probably wondering if it’s okay to install a smart switch without grounding it.

Smart switches will work without using a ground wire. It is okay to replace a switch and not use ground if one is currently not used. However, if installing a new switch or altering wiring, the circuit must be brought up to current NEC code by a licensed electrician, which includes a ground wire.

The ground wire is important for proper grounding, but does not affect how a switch works. 

Ideally, this question should be answered by a licensed electrician in your area, as they will know what code your local municipality requires. They will use the NEC (National Electric Code) published by the National Fire Protection Association (NFPA). The question is what year of the standard that the city currently requires.

All versions of the NEC standard can be found on the NFPA website, located here.

Why Are Smart Switches Grounded?

The ground wire is a safety mechanism in case there is a fault or a problem with the switch. 

In an electrical circuit for a switch, there is what’s known as the live wire, the load wire, and the return wire. The live wire is the wire that supplies the power. The load wire connects to whatever the load is, for example, a light bulb. When you toggle the switch, it connects the live wire to the load wire. . 

The electric current flows through the live wire, to the load wire, through the load (the light bulb), and finally through the return line, also known as the neutral. In newer homes, you will see the neutral wire in the junction box for the switch. 

A fourth wire, either a bare copper wire or with a green insulator, should also be in the junction box. If not, check if your junction box is made of metal. The ground wire may be attached directly to the junction box, but not visible. 

If something ever goes wrong with your switch and a short circuit happens, the ground wire provides an additional path for the current to return safely to the ground without endangering anyone or anything. 

If a short circuit did occur, the current would flow through the ground wire, causing a blown fuse or tripped circuit breaker – an outcome much more preferable than the fatal shock that could result if the current was not grounded.

What Happens If You Don’t Ground The Switch?

The ground wire provides a path from a faulty circuit directly to the earth’s ground. 

Here is an example. In the event of a partial short, where there is not enough current to trip the breaker, the ground will carry the current. If you happen to come in contact with any of the adjoining metal, you won’t get shocked. If a full short occurs, the current causes the fuse to blow or the breaker to trip and the circuit is turned out. 

By grounding your electrical system, you are giving it somewhere to go other than into you – possibly saving your life. 

The worst case scenario of not having a grounded switch is that someone gets shocked with 120 V, which can be fatal. The second worst case scenario is that a short circuit causes a fire, resulting in potential loss of life and loss of property. At a minimum, a fire will cause major property damage and smoke damage throughout the house.

As you can see, grounding is an important part of your home’s electrical system and keeping you and your family safe. There is a reason it’s there.

In Conclusion

My recommendation is to be safe and contact a licensed electrician if you need help.

The ground wire is a safety feature., but it is not a functional part of the circuit.Most likely your smart switch will work just fine without a ground wire attached, but there are a few that check to see if it is connected. Higher end smart switches will not work unless ground is connected. 

For example, some Lutron switches require a ground to work. That is one reason I like Lutron. They care about your safety and aren’t willing to sacrifice safety for higher profit margins.

If you don’t see a ground wire in the junction box, chances are you have a ground. Check all around the junction box, even behind it, for a bare copper wire. If you need to extend it, you can get a piece of copper wire and tie it to the ground with a wire nut.

In the past, regular switches were rarely grounded. It’s only the newer smart switches that require a ground.

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