Are There Fuses In Dimmer Switches?

Fuses are clever bits of kit that help to protect the wiring in the circuit.

Their purpose is almost like an airbag in a car – if something goes wrong in the circuit, such as a bulb blowing, that causes too much current to flow, then the fuse’s internal wire will melt.

This causes the fuse to pop and break the circuit, killing the power.

Not everything has a fuse, though – they add an extra cost, so it depends on the manufacturer of the product and whether they think it’s necessary to install one.

So, are there fuses in dimmer switches?

Older dimmer switches did have fuses to protect the switch or prevent dangerous temperatures if the switch got too hot. Unlike most fuses, they were integrated and difficult to replace. Modern dimmers have generally stopped using fuses.

In this article I’m going to explain:

  • Which dimmer switches have fuses, and what their purpose was
  • How easy (or not) the fuses are to replace
  • The reasons modern dimmers don’t have fuses
  • Whether a faulty switch can blow the fuse

Is There A Fuse Inside The Dimmer Switch?

electric fuse box

Not all dimmer switches have a fuse.

It tends to be older ones that do, but they’ve decided not to include a fuse for most modern brands.

The fuses tended to be integrated, too, rather than something you could simply swap out.

There’s no real downside to including a fuse in a dimmer switch, so I’ll explain why they were used and the reason that most modern dimmers don’t incorporate them anymore.

However, if you have an older dimmer switch that includes a fuse, don’t be in a rush to replace it if it’s working fine.

What Was The Purpose Of The Fuse?

There were two main reasons for having a fuse in a dimmer switch. The first was simply to protect the dimmer in case of the light fitting failing.

Electrical components, as clever as they are, are delicate. For example, if a lamp blows on a circuit, there can be a surge of current.

The fuse would protect the dimmer switch by also blowing, which would break the circuit completely.

That way, the increased current couldn’t do any permanent damage to the dimmer.

Even more importantly, the fuses would serve as thermal protection.

This would mean that if the circuitry in the dimmer got too hot due to a surge in power, then the fuse would blow.

This would stop the switch from getting so hot that it caught fire, which could cause massive damage to your property as well as just being dangerous for your well-being.

Dimmer switches can get warm, but if they’re hot, then that’s the sign of a problem – switch off the light and have it looked into before you continue to use it.

Can Internal Dimmer Switch Fuse Be Replaced?

dimmer switch

What’s interesting about the fuses used in older dimmer switches is that they weren’t really the kind you can pop out and replace.

In most cases, they were integrated into the switch itself.

While most fused appliances or electrical items have a small compartment, you can either flip open or unscrew to remove a fuse. In dimmer switches, it was a lot more complex. It wasn’t designed to be something that your average homeowner could do.

What this means is that to protect the dimmer switch, the fuse was actually pretty redundant – because once the fuse blew, you’d likely have to replace the whole dimmer switch anyway.

It was still useful, and many experienced electricians lament the lack of fuses in dimmers (especially with cheap, poor-quality light bulbs available online).

That’s because even if it was pointless protecting the switch itself, it would stop overheating and it would protect the rest of the lighting circuit too.

Why Don’t Dimmer Switches Have Fuses Anymore?

installing a light switch

Fuses in dimmer switches are pretty beneficial, so why have modern dimmers stopped including them?

There’s a simple reason – cost.

Manufacturers like to keep the prices of their production down. In theory, they want to pass on those savings to you, the customer.

Fuses aren’t necessarily really expensive, but they are an additional cost that isn’t technically needed.

So while your dimmer switch is probably cheaper because it doesn’t include a fuse, that doesn’t necessarily save you money in the long term.

Because if your dimmer doesn’t have one, then any time a bulb blows, you could potentially see damage to the dimmer.

And while a lightbulb might cost you around $1 to replace if it’s incandescent, a dimmer switch is usually a lot more than that.

You can probably get a really basic one for under $10 but most start at $15 on Amazon.

That’s why it’s so important to not buy cheap bulbs – they’re much more likely to break.

Therefore you may end up having to repeatedly payout not just for new lights but also new dimmer switches.

Another common cause of dimmer switches being damaged is if your bulbs are installed ‘upside down’ or facing upwards.

When the bulb blows, a piece of filament can sometimes fall down and potentially short the circuit.

If your bulbs face upwards, then there’s a slightly higher chance of your dimmer being damaged.

Of course this is an extreme edge case, and with LEDs taking over the world, this scenario is extremely unlikely.

Can Faulty Dimmer Switch Blow The Fuse?

turning the fusebox

Yes, a faulty dimmer switch can also cause the fuse to blow.

If the switch’s wiring has been damaged in any way (which can often happen if you unscrew it to decorate the walls around it) or a wire has just come loose, then it could cause a surge that would blow a fuse.

Another potential reason is if your dimmer switch cannot handle the circuit you’ve installed it on.

Dimmer switches have a total wattage limit, and you need to make sure that that’s above the wattage of your bulbs in total.

It’s common for dimmers to be rated up to 600 Watts for incandescent bulbs or 150 Watts for LED and CFL bulbs if they are compatible.

600 Watts is a decent limit – it’s the average for 10 standard incandescent bulbs, so unless your dimmer controls multiple rooms, you’ll probably be fine. 

Final Words

Don’t be too alarmed by some of this article – it certainly isn’t my intention to put you off buying a dimmer switch.

As long as you’re sensible enough to buy quality bulbs to go with your switch, you will not have any problems.

But because modern dimmers don’t have fuses, I would avoid matching them with cheap bulbs.

As soon as those bulbs pop, there’s a good chance your dimmer will, too – and you don’t want to keep swapping the dimmer with your bulbs.

Have you got older dimmer switches installed at home, and do they have fuses? Any problems with blown lights and switches?

Leave a comment and let me know.