Can a light switch go bad? How to tell

Can a light switch go bad? The answer surprises some people, but yes, being an electromechanical device, there are parts in a light switch that can wear out or become oxidized over time and eventually stop making good electrical contact. In this blog post, I’ll explain how to tell if your light switch is going bad and if it’s time to replace it.

Your light switch clicks

can a light switch go bad?
If a light switch shows certain symptoms, such as light bulbs burning out quickly, sparks, or making weird sounds, that can be an indicator it’s time to replace it.

One symptom I’ve frequently heard is that a light switch that clicks means it is going bad. Depending on what causes the click, that may not always be the case. In the past, some lights switches gave a mechanical click as you turned them on. I even found a stash of new old stock, unused light switches from a long defunct hardware store chain in the garage of a house I was renovating. Those switches clicked audibly when I operated them.

To know for certain if a click in the switch is problematic or just the way it was made, you can unscrew the bulbs from the light fixture so the switch isn’t controlling anything. With no load on the switch, there won’t be any electrical current. If you flip the switch and it still makes a noise with the bulbs unscrewed, that’s a mechanical sound. If the click goes away without a load, that’s the sound of electricity fighting resistance, and you don’t want your light switch to be putting up a fight.

All that said, sometimes people replace old light switches just because they want a quieter switch. If a click from your light switch bothers you, a new, quiet light switch is a quality of life upgrade that doesn’t cost a lot of money. New light switches cost about $1.

Sparks and other noises from the switch

Similarly, if you hear other noises when you flip a light switch, those noises are usually an indicator of electrical resistance. And if the problem seems to become more frequent over time, you’re not imagining things. That sound you hear is called arcing, and arcs attract dust and deposit the dust on the metal surface nearby. Every time this happens, it makes the arcs happen more frequently.

Sparks from a light switch

Generation X may remember parents telling us not to operate a light switch with wet hands, because it causes a spark and it could shock you. There’s less danger of that today since grounded light switches are much more common now.

If you operate a switch with dry hands and it sparks, that’s a good indicator of the switch is going bad and needs to be replaced.

Light bulbs burning out prematurely

Energy efficient light bulbs do more than save money. They also last longer. I got into the habit about 20 years ago of writing the date of purchase on my bulbs because I bought a bad batch that only lasted a few months, and back then bulbs were really expensive, so it meant I wasted a lot of money.

I learned two things from doing this. Sylvania bulbs gave me more problems than any other brand, and my bulbs didn’t last as long in bathrooms, regardless of brand.

I replaced the switches in my bathrooms and solved my problem. Most of the bulbs in my bathrooms are between 5 and 7 years old now.

Can you fix a light switch that went bad?

In theory, you can fix a light switch, but it usually is more trouble than it’s worth. New light switches cost around $1 and you will spend nearly a dollar in cleaning supplies and effort refurbishing a light switch that went bad.

But if you are a preservationist and you want period correct switches in an older house, cleaning an old switch in an ultrasonic cleaner will revive them if the problem is dirt or oxidation. If the problem is worn contacts, an ultrasonic cleaner won’t help.

So fixing a light switch is risky, but sometimes possible. You’ll have to decide if it’s worth the trouble for you.

If the light switch is dirty on the outside, it must be bad, right?

I’m sure you’ve heard people say their rule is if it’s dirty on the outside, it’s dirty on the inside. When it comes to light switches, dirt on the outside could be an indicator that there is dirt inside as well. But the opposite isn’t necessarily true. You can clean the outside of a switch, but cleaning the outside of a switch doesn’t do anything to help inside a switch.

And the things that cause a switch to get dirty on the outside aren’t the same as on the inside. The outside of switches gets dirty from use. The inside of switches get dirty from arcing and humidity as much as anything else. A light switch in a garage in Arizona doesn’t get much humidity, so it will last longer than a switch in a garage in Missouri, where it will be exposed to humidity accompanied by greater swings in temperature.

So the rule that a switch is similarly clean on the outside and on the inside is based on the assumption that cleanliness and humidity are related. That’s not a reliable assumption.

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2 thoughts on “Can a light switch go bad? How to tell

  • April 18, 2023 at 12:17 pm

    I live in a 120 year old house that had electricity from day one, so I know they wear out. My house still has a couple of lightly used original switches in the basement, but we had to replace the others (as well as the original outlets) because they wore out. We weren’t concerned with preservation — this house is old but not historically significant, and about the same age as entire blocks of nearby houses — so we didn’t make any attempt to extend the lives of the old ones.

    Some of those early switches took forms that aren’t commonly seen now. There were a number of switches with on and off pushbuttons; those went out of fashion many years ago. There were also a couple that were rotary switches rather than up-down; those have the disadvantage of not giving a clear visual indication of being on or off.

    The original outlets were quite distinctive because they had horizontal slots along with the vertical ones, interconnected. That wasn’t keying for higher current outlets, as it can be now — it was for DC! Way back then it wasn’t clear whether AC or DC would prevail, so outlets were made that could be used for either standard. (DC devices used plugs where the two prongs were collinear rather than parallel.)

    The builder was clearly also into belt and suspenders, as it were. Many of the locations that have wall-mounted lamp sconces also have gas pipes leading to them, as a provision for gaslights. We don’t believe they were ever used; they don’t have gas flowing to them now (they’re disconnected in the basement) and may never have had gas, but if that whole electricity thing hadn’t worked out they would have been easy to connect. The house originally had four circuits that went to a fuse box on the second floor; that box has long since been decommissioned and replaced with a larger breaker box in the basement. We also have knob and tube wiring in the walls, also decommissioned.

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