Robotic Pool Cleaner Power Supplies and Transformers

How robotic cleaners get power

Robotic pool cleaners are self-contained units that do not use the pool's circulation pump. According to the U.S. Environmental Protection Agency's ENERGY STAR program, robotic pool cleaners are powered by low-voltage electricity and collect dirt in built-in filters. This low-voltage power comes from a transformer that converts standard household alternating current (AC) into a safer direct current (DC) or low-voltage AC that the robot can use.

The transformer is typically housed in a power supply unit that sits outdoors next to the pool. That unit is not waterproof, so it must be placed away from splashing, rain, and standing water. Many models include a short cable that connects the unit to a standard wall outlet, and a longer cable that goes into the water to the robot.

What voltage means for buyers

Voltage is the electrical pressure that pushes current through the cable. Robotic cleaners operate at low voltage, which is why they are considered safer than high-voltage pool equipment. The transformer reduces the voltage so that if the cable is damaged underwater, the risk of electric shock is much lower than with line-voltage devices.

When comparing models, you will see the input voltage (the household voltage the transformer accepts, such as 110-120V in North America) and the output voltage (the low DC or AC voltage that feeds the robot). Output voltages vary by manufacturer and model. Higher output voltage does not automatically mean better cleaning; it is simply part of the unit's design. What matters more is that the power supply is matched to the cleaner's requirements, which the manufacturer sets.

If you are buying a cleaner from a different country or from a brand that sells multiple regional versions, check that the transformer is rated for your local mains voltage. Many power supplies accept a wide range, but some are region-specific. A mismatch can prevent the unit from turning on or can damage the electronics.

Cord length and reach

The cable that connects the power supply to the robot determines how far the robot can travel from the unit. A longer cord allows the robot to cover a larger pool and lets you place the transformer farther from the water's edge. A cord that is too short for your pool will limit where the robot can go, often leaving the far end unclean.

Cable length is usually listed in the cleaner's specifications. For a typical in-ground pool, a cord of at least 40 to 50 feet is common, but larger pools may need a longer cord. Above-ground pools usually have shorter requirements because the pool is smaller and the power supply can sit close to the edge. Check the manufacturer's recommended cord length for your pool size before buying.

When the cable is in the water, it can tangle or snag on steps, ladders, and drains. Manufacturers design swivels and anti-tangle rings to reduce this, but the physical reach is still set by the cable length. If your pool is long or has an irregular shape, a longer cable will give the robot more freedom to navigate to every corner. For guidance on measuring your pool and matching the cable, see our cable length guide.

Transformer placement

The power supply must be placed on a firm, level surface that is at least a few feet away from the water's edge to keep it dry. It should never sit on the ground where puddles, sprinklers, or lawn irrigation can reach it. A common practice is to set it on a pool deck or a small stool, with the cable routed neatly to the water.

The power supply's outlet plug should be protected by a ground-fault circuit interrupter (GFCI), which is the same outlet type recommended for outdoor electrical use in the United States. GFCI outlets shut off power when they detect a ground fault, reducing the risk of electric shock. Before installing your cleaner's transformer, confirm that the outdoor outlet is GFCI-protected.

Some power supplies come with mounting brackets or a hook so you can hang them on a wall or railing. That keeps the unit elevated and away from moisture. If your model does not include a mounting option, a small shelf or a clean plastic bin with a hole for the cable can work, as long as it does not trap heat and the cable does not bend sharply at the connection.

Protecting the connection

The point where the cable enters the water is a frequent source of problems. Twists and sharp bends at the connector can strain the cable and cause intermittent power loss. Keep the cable straight near the waterline and avoid pulling it taut across sharp pool edges. Many cleaners include a strain relief or a loop that you can use to anchor the cable.

If you store your cleaner out of the water between uses, unplug the power supply and coil the cable loosely. Never wrap the cable tightly around the power supply while it is still connected, as that can bend the internal wires. If the cable becomes frayed or the connector cracks, replace it rather than attempting a DIY repair, since a damaged low-voltage cable can still cause overheating at the connection. For more on maintaining the cord and connections, see cable management and power cord maintenance.

Choosing the right setup

For most homes, the power supply that comes with the cleaner is the correct one. The main buying decision is whether the cord is long enough for your pool. If you are between two otherwise similar models, choose the one with a longer cable, because you cannot easily extend a robotic cleaner's power cable without affecting the voltage and warranty.

Cordless robot cleaners eliminate the transformer and cable entirely, because they use a built-in battery and a charging dock. If you have a very long, irregular pool, or if you simply do not want to deal with a cable on the pool deck, a cordless model may be more convenient. However, corded robots do not need battery recharging mid-cycle, and their runtime is effectively unlimited as long as power is available. For a detailed comparison, see cordless vs. corded robotic pool cleaners.

Always check the manufacturer's instructions for the minimum distance between the power supply and the water. While low-voltage power is safer than line voltage, the transformer itself is not waterproof. Keeping it dry also prevents corrosion on the prongs and outlet, which can lead to overheating.

What to pick for your pool

Questions

Does a robotic pool cleaner need a transformer?

Yes, unless it is a cordless model. Corded robotic cleaners receive power through a transformer that steps down household AC to a low voltage that is safe for underwater use. The transformer is part of the power supply unit that sits outside the pool.

What voltage does a robotic pool cleaner use?

Output voltage varies by model, but it is always low-voltage DC or low-voltage AC. The exact value is listed in the manufacturer's specifications. You do not need to match a separate voltage rating as long as you use the power supply that comes with the cleaner.

Can I extend the power cord of my robotic pool cleaner?

You should not extend or modify the power cord because it is sized by the manufacturer to deliver the correct voltage and current without excessive drop. Extending it can lead to voltage drop, overheating, or tripping of the GFCI. If the cord is too short, consider a cordless model instead.

Where should I place the transformer for my robotic pool cleaner?

Place the transformer on a dry, level surface at least a few feet from the pool edge, out of splash zone and away from sprinklers. It must never sit in standing water. If possible, hang it on a wall or use a small shelf, and plug it into a GFCI-protected outlet.

Is it safe to use a robotic pool cleaner in a saltwater pool?

Yes, most robotic cleaners are designed for saltwater pools, but the transformer should still be kept away from the water and from direct exposure to salt spray. Salt can accelerate corrosion on connectors, so rinse the cable and connector with fresh water after use if you have a saltwater pool. See our saltwater compatibility guide for more.