How to Install an LED Lighted Shower Niche: Step-by-Step Guide

Isaac Ostrom
Oct 20
7 min read

Updated: Oct 28

Hey guys — Isaac here, your Tile Coach. Today, I’m walking you through a full job-site install where we’re adding LED lighting inside a shower niche. Yep, we’re going to wire it, waterproof it, and dim it — all while keeping it safe and professional.

Now, before I go any further, let me be super clear: if you’re not a licensed electrician, don’t attempt this yourself. There’s a lot of 120-volt wiring in this setup, and one mistake can be dangerous. If you’re not trained or confident with electrical work, get a pro to handle the wiring side. You can still follow along to understand how it all fits together and communicate better with your trades.

That said, this is one of my favorite modern upgrades for showers — a lighted niche that looks like something out of a high-end spa. It’s clean, functional, and, when done right, totally waterproof.

So grab your notepad, because I’m breaking this one down step by step — from wiring and dimmer setup to waterproof soldering and final testing.

(Real Jobsite Walkthrough and Pro Tips for Waterproof LED Lighting)

Key Takeaways [TLDR for Homeowners & Pros]

Use an IP65 or IP68 waterproof-rated LED strip — regular LED strips won’t survive in a shower.
Always install a dimmer designed specifically for LED lights (regular dimmers won’t work).
Pull 120V AC power to the transformer, then convert it to 12V DC low voltage for the LED strip.
Use heat-shrink tubing and silicone sealant for watertight solder joints.
Mount the LED strip in a Schluter SG110 aluminum profile for protection and a clean finish.
Keep the transformer accessible in the attic for future maintenance.
Match polarity (+ to +, – to –) — reverse polarity will fry the LED strip.
Always test the system before closing up the walls.
Use shielded wire if your low-voltage cable crosses over 110V lines to avoid interference.

Understanding the Setup

For this install, I’m working in a bathroom where the shower and closet share a wall. That’s a huge advantage, because it gives us easy access to power.

We’re running a new 120V AC line from the closet’s existing switch box up into the attic, where it will feed a low-voltage transformer. The transformer converts 120V to 12V DC, which is safe and ideal for LED lighting inside the shower.

We’re also adding a new dimmer switch in the same box as the closet light switch, so we can dim the LED niche lighting separately.

The Dimmer Switch

This part’s critical — you can’t just use any dimmer.

You need one specifically made for LED lighting. The wrong dimmer can cause flickering, humming, or even damage the transformer.

The one I’m using here is rated for low-voltage LED applications and comes with a specific part number. Always double-check your dimmer’s compatibility with your LED system and transformer before wiring it in.

We’re replacing the single-gang box with a new double-gang remodel box, so we can keep both the closet switch and the LED dimmer together in one clean setup.

Step 1: Running Power and Setting Up the Switch

Once the dimmer and plan are figured out, it’s time to get power from the existing circuit.

Here’s the setup:

Hot line (black) brings power in.
Switched leg (red) sends power to the LED transformer.
White is the neutral, and bare copper is the ground.

We’re tying into the hot side of the existing closet switch, not the switched side. That ensures the LED circuit always has live power independent of the closet light being on or off.

After identifying the hot line, I install the double-gang box and pull 14/2 Romex (standard residential wire) up the wall into the attic. This new line will feed our LED transformer.

Step 2: Fishing the Wire Through the Attic

Time to head up top.

Once in the attic, we locate the new Romex line and run it to where we’ll mount the LED transformer. I always secure Romex with staples within a few inches of every junction box — that’s just code compliance and good practice.

The transformer location should always be accessible, even after the job is complete. You’ll want to reach it later if you ever need to replace a driver or troubleshoot.

Step 3: Preparing the LED Strip

Now for the fun stuff — the LED strip itself.

I’m using an IP65-rated LED strip. That means it’s designed for wet locations like showers and has a waterproof silicone sheath over the strip. Anything less than IP65 is a no-go — standard strips will fail or short out when exposed to moisture.

The strip slides into a Schluter SG110 aluminum profile, which mounts into the tile during installation. It’s one of the cleanest and most durable ways to protect the LED while keeping it flush with the tile surface.

I’ve already got the Schluter profile installed with the tile, so now we just need to pull the low-voltage cable up through the wall to connect it.

The cable I’m using is 16-gauge, two-conductor wire. It’s not shielded, but if your low-voltage wire runs parallel to 110V lines, it’s a good idea to use shielded wire to prevent interference.

Step 4: Soldering and Waterproof Connections

Here’s where the details matter most.

Whenever you join wires, especially in wet areas, you have to make watertight connections. For that, I always use heat-shrink tubing — two sizes:

Small ¼-inch shrink for the solder joints
Larger ⅜-inch shrink for the outer cable jacket

Before you solder, slide your heat shrink onto the wires — if you forget, you’ll have to cut and start over. Once the joint’s soldered, slide the tubing over the connection and shrink it down with a heat gun.

I also like to use silicone sealant to fill any entry points or exposed cable ends. It’s an extra layer of moisture protection and keeps corrosion out.

The goal is to make a completely sealed connection that’ll hold up for years behind the tile.

Step 5: Pulling the Cable and Mounting the LED

After making your watertight connections, it’s time to pull the low-voltage cable into the niche cavity using a pull string you set earlier.

Pull it gently to avoid stressing the cable. Once it’s through, connect it to the LED strip — red to red (positive), black or purple to black (negative).

The LED strip has pressure-sensitive adhesive backing. Peel and press it into the aluminum profile, applying firm pressure as you go.

At the ends of the strip and at the cable entry hole, I like to apply a bead of 100% silicone. This seals out any stray moisture and prevents the adhesive from peeling back over time.

If the strip ever fails down the road, the cable stays loose inside the cavity so you can pull the old strip out and slide a new one in without tearing up your tile.

Step 6: Installing the Transformer

Back in the attic, we hook up the 120V AC input and 12V DC output to the transformer.

High-voltage side:

Black → black (line)
White → white (neutral)
Bare copper → green (ground)

Low-voltage side:

Red → red (positive)
Purple or black → black (negative)

Make sure the polarity is correct — LEDs are polarity-sensitive, and reversing them will prevent the strip from lighting.

All connections go inside a junction box with strain-relief clamps, and we label the box for future maintenance.

Step 7: Final Wiring at the Switch Box

Now that the attic wiring’s done, we can wire the switches.

The closet light switch stays on its original circuit. Our new dimmer switch ties into the constant hot wire and controls the line feeding the LED transformer.

I like to bundle all grounds together with a copper crimp sleeve so you only have one pigtail going to the box. It keeps everything neat and secure.

When everything’s wired up, we can reinstall the switches and test the system.

Step 8: Testing and Dimmer Adjustment

Turn the power back on and check your work.

When you flip the dimmer on, your LED niche should light up immediately. The dimmer will let you adjust the brightness — all the way down for a soft nightlight glow, or up to full power for bright accent lighting.

Because LEDs are so efficient, you can leave them on at a low setting 24/7 for pennies a month.

I always finish up by aligning all the switch plate screws vertically — it’s a little OCD detail, but I think of it like centering a shower drain. Clean details make for professional finishes.

Step 9: Final Cleanup and Inspection

Before wrapping up, check these details:

All connections are tight and protected.
Heat shrink is sealed and cooled.
Silicone is cured around all cable penetrations.
Transformer is labeled and accessible.
Polarity is confirmed.

Once everything passes, go ahead and close up your boxes and enjoy the results — a seamless, glowing niche that adds serious “wow” factor to any shower.

Maintenance Tips

Access: Always mount the transformer where you can get to it later (like an attic). Don’t bury it.
Label the circuits: Makes troubleshooting way easier later on.
Avoid flicker: If your LED strip flickers, check for loose polarity or an incompatible dimmer.
Repairing strips: If a section goes out, you can cut and splice a new one in — just remember to reseal the ends with silicone.

Frequently Asked Questions (FAQ)

Q1: Can I use any dimmer for LED lighting?

No — you need a dimmer rated for LED low-voltage systems. Regular dimmers don’t communicate correctly with the driver and can cause flickering or burnouts.

Q2: What does IP65 or IP68 mean?

Those are waterproof ratings. IP65 handles splashes and steam, while IP68 can handle full water submersion. Always use IP65 or better for showers.

Q3: Can I install LED lighting without a professional?

Not if it involves 120V wiring. Always bring in a licensed electrician for the high-voltage side. You can install the low-voltage LED strip and niche components yourself after that.

Q4: Do I need to use heat shrink and silicone?

Yes — absolutely. Those two things make the difference between a 3-month light and a 10-year light.

Q5: What if I ever need to replace the strip?

No problem. The silicone seals can be cut, and the strip slides right out. Just feed the new one through the same cavity using the pull wire.

Wrapping It Up

And that’s it — we’ve installed a fully functional, waterproof, and dimmable LED lighted shower niche from start to finish.

This project combined electrical wiring, waterproofing, and precision finishing, and the end result looks incredible.

A few reminders before we go:

Always verify polarity before powering up.
Keep the transformer accessible.
Use waterproof-rated materials — don’t cut corners here.

If you do this right, you’ll end up with a modern, maintenance-free feature that takes your tile work to another level.

If you found this guide helpful, share it with other tradespeople or DIYers in the TileCoach Forum

Until next time — keep learning, keep building, and as always, keep your work clean and professional.