Can You Control a Swimming Pool Light with a Hot Tub Spa Pack?

Updated September 2026. I’ve checked the light outputs on current Balboa and Gecko spa packs (my old “1A at 10–12V AC” figure needed updating), added a compatibility table, the UK safety rules for lights in a hot tub, and what’s included with my lights today.

In short, the answer is yes. You can control a swimming pool grade light from a hot tub spa pack, and switch it on and off with the light button on your topside. But you can’t just plug a pool light into the pack. Here’s why, and how I solved it.

The old problem

When you build your own hot tub, there’s nothing better than having it lit up at night. But the LEDs designed for plastic shell tubs aren’t suitable for concrete or block tubs. They aren’t big or bright enough for a tiled tub full of water.

The obvious answer is a swimming pool light. So what’s the problem? In my experience there were several:

• The “swimming pool tax”, as I call it. They were expensive.
• The supply chain was ropey at best, with long lead times.
• You needed a specialist power supply that cost the earth.
• The lights themselves were, in my opinion, too big and bulky, and many need a niche set into the wall.

That’s why I created the buildahottub.com light: slim, bright, easy to install, and it doesn’t cost the earth. There’s more on choosing and fitting lights in Underwater hot tub lighting made simple and The ultimate guide to hot tub lights.

Why can’t you plug a pool light into a spa pack?

The problem was that a pool light draws far too much current to be plugged straight into a spa pack. If you press the light button on your topside and expect the light to come on, it won’t end well. Your board can go bang. I learnt that the hard way on my own build.

When I first wrote this, I said most spa packs only allow about 1A at 10–12V AC from the main board. I’ve checked the current tech sheets, and the real figures are a bit higher, but the point stands:

Spa pack	Light output	Roughly
Balboa BP601 (UK/EU)	10V AC, 2A max, shared with Chromazon3 (tech sheet)	20W
Balboa BP8	10V AC on/off, 2A max, shared with Chromazon3 (tech sheet)	20W
Gecko in.ye	12V DC, 1.3A max (parts4tubs.co.uk listing)	16W
Super Slim pool light	12V DC, 3A power supply (product page)	35W

So a pack’s light output is built for the small LED lights that come with shell tubs, not a proper pool light. There’s a second issue too. Pool lights, like most LEDs today, run on DC, while Balboa packs still give an AC light output. Gecko’s in.ye gives DC, but nowhere near enough of it.

That meant that, until the connection kit, you had to fit a separate switch for your light and couldn’t use the topside to turn it on.

The solution: a relay the pack can drive

If you’ve read the blog or watched the YouTube channel, you’ll know my background is in technology. I spent a number of years trying to solve this. The problem was that traditional relays are designed for a low DC voltage to switch a high AC voltage. That’s not what we needed. We needed a low AC voltage from the spa pack to switch another low DC voltage that powers the LED.

For a while there was a workaround using a power strip, but it was only available in the USA, so it was no good for my customers everywhere else.

Simple in theory, but it took me the best part of four years to come up with a solution and find the right components. Bingo! The buildahottub.com Hot Tub Light Connection Kit was born.

What is the Hot Tub Light Connection Kit?

The connection kit is a bridge between a swimming pool grade light and the spa pack that runs your hot tub. With it, the standard topside switches your pool light on and off.

• Input: a 2-pin AMP connector on a 50cm (20in) cable. This plugs into the light output on your spa pack.
• Output: a switching cable. Think of the box as a switch. It’s wired into the low-voltage side of your light’s power supply, between the 12V DC supply and the light, following the wiring diagram that comes with it.

Voilà! The light button on your topside now turns your pool light on and off. The kit only draws 0.04A (40mA) from the pack, which is far less than any pack can supply. In other words, your pack won’t go bang.

Specifications

Dimensions	120 × 60 × 30mm (5 × 2.5 × 1in)
Input (from the spa pack)	9.5–12V AC or DC
Current draw from the pack	0.04A (40mA)
Switching load	12V DC, 24V DC, or up to 240V AC, at up to 10A

Which lights and spa packs does it work with?

Lights

The kit switches 12V DC, 24V DC and up to 240V AC at 10A, so it works with pretty much any swimming pool light. On the 12V DC side, you can run up to three of my 35W lights through one kit. My advice, though, is to keep everything in and around the water low voltage, and switch the low-voltage side. If anything on the mains side needs wiring, that’s a job for your electrician.

Spa packs

• Packs with an AMP light connector, such as Balboa: plug straight in. The input accepts anything from 9.5V to 12V, AC or DC, which covers most packs.
• Packs with a different light connector, such as some Gecko packs: the input voltage is fine, but you may need to change the connector to fit your pack.
• ACC packs: don’t. ACC’s SmartTouch 1000 guidelines say not to connect the buildahottub.com pool light to the control unit, as it isn’t compatible. Use a separate switch instead.

Not sure what your pack has? My guides to reading spa pack wiring diagrams and identifying a Balboa circuit board will help. If the light button doesn’t do anything once it’s connected, check your pack’s setup and light timer settings. See Configuring a Balboa spa pack.

What about the buildahottub.com lights?

The good news is that my Super Slim DIY Hot Tub / Swimming Pool Light comes with the spa pack connection kit, along with its 12V DC power supply. It’s 8mm thin, surface mounted with no niche, IP68 rated and RGBW. You set the colour with the remote, and switch it on and off from the tub with your topside. In the UK it’s also available from parts4tubs.co.uk.

For smaller tubs, or to put several lights round a plunge pool, there’s also the Super Slim 6W spot light, in 4 packs and 6 packs. These come with their own power supply and remote. If you want to switch them from your topside, check with me through the shop before you order.

Safety: keep it low voltage

Water, wet people and electricity need respect. In the UK, the IET’s guidance on outdoor hot tubs applies the swimming pool rules in BS 7671 Section 702. Lights in or right next to the water should be supplied by SELV (separated extra-low voltage) at no more than 12V AC or 30V ripple-free DC, and switchgear and junction boxes shouldn’t sit within 2m of the water (SELV junction boxes are the exception). In practice:

• Keep the light’s power supply and the connection kit in the control room, well away from the water, in a dry, ventilated spot.
• Only put low-voltage cable into the tub.
• Have your electrician check anything on the mains side. In the USA, NEC Article 680 covers underwater lights, so check with your inspector.

There’s more on supplies, RCDs and GFCIs in Hot tub wiring explained.

Common mistakes

• Plugging a pool light straight into the pack’s light output.
• Assuming every pack’s light output is the same. Some are AC, some are DC, and they use different connectors.
• Connecting the light to an ACC pack.
• Mounting the power supply somewhere damp, or inside the tub surround with no ventilation.
• Forgetting to run a conduit or sleeve for the light cable before the walls are rendered.

Planning your own build?

Lights are much easier to fit when the cable route is planned before the walls go up. My DIY hot tub plans include the plumbing layout and a full parts list, so you know where everything goes before you start.

FAQs

Can I plug a pool light into my hot tub spa pack?

Not directly. A spa pack’s light output is only designed for small shell-tub LEDs, typically around 10–12V at 1–2A. A proper pool light needs more, so use a relay such as the connection kit, which lets the pack switch the light’s own power supply.

What voltage is a hot tub light output?

It depends on the pack. Balboa’s BP601 and BP8 give 10V AC at up to 2A. Gecko’s in.ye gives 12V DC at up to 1.3A. Check the tech sheet for your pack.

Will the connection kit work with a Gecko pack?

The input takes 9.5–12V AC or DC, so the voltage is fine. It’s supplied with an AMP connector, so you may need to change the plug to suit your pack.

Can I still change the light colour?

Yes. The topside turns the light on and off. You choose the colour or mode with the light’s remote.

How many lights can one connection kit switch?

It switches up to 10A, which is enough for up to three of my 35W Super Slim lights on the 12V DC side.

Got a question about lighting your own tub? Drop it in the comments below. I read them all.

Cheers,
Andi

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Thanks - Andi

 

Hi, Andi here. I own Buildahottub.com and also write all of the articles and info pages on the site. Some years back now, I built my own hot tub but struggled to find the information I needed. So, once my tub was complete, I started this website to help others in their own pursuit of hot tub and plunge pools DIY building information.

Fast forward to 2025, I've helped over 1400+ DIY customers just like you all over the world build hot tubs and pools. Have a good look around the site, there are lots of resources here. Please do get in touch if I can help you. - Cheers, Andi