If your Eight Sleep Hub periodically reboots in the middle of the night, shows a flickering LED light ring, or emits an irregular electrical clicking sound, dirty power or an unstable wall outlet may be compromising the device. A fluctuating power supply stresses the Hub’s high-draw thermoelectric cooling engine and can permanently damage the internal control board.
Quick Answer
A pulsing or rebooting Hub is typically caused by a loose outlet receptacle, an overloaded bedroom circuit, or an inadequate power strip. Plug the Hub directly into a grounded 15A or 20A wall outlet, verify that the line voltage remains stable when the thermal engine engages, and replace any unrated extension cords immediately.
What Causes “Pulsing” Power in Smart Beds?
An Eight Sleep Hub draws varying levels of electrical current depending on its operating state. During idle standby, power draw is minimal. However, when the Peltier thermal engine shifts into maximum cooling or heating mode and the internal pumps and fans spin up, electrical current demand increases significantly.
[ Unstable Circuit ] ──> Voltage Drops Under Load ──> Hub Brownout / Reset
│
▼
Pulsing Lights /
Failed Thermal Engine
If the electrical circuit supplying the Hub has high resistance, caused by worn outlet spring contacts, back-stabbed receptacle wiring, or a cheap surge protector, the line voltage drops the instant the chiller demands power.
This drop causes the Hub’s internal power supply unit (PSU) to enter an undervoltage protection loop: the Hub reboots, the load disappears, the voltage recovers, the Hub tries to power the chiller again, and the cycle repeats. To the user, this appears as pulsing indicator lights or erratic reboots.
Signs Your Power Supply or Outlet Is Failing
Before assuming the Hub itself has failed, examine these common physical and operational symptoms:
1. Rhythmic LED Flashing or Clicking
If the Hub’s front indicator flashes and you hear a soft, repeating click from inside the chassis or the external power brick, the power supply is failing to sustain current under load. If you notice any discoloration or unusual heat around the power brick, review Melted Eight Sleep Power Cord? What to Do with Faulty 2026 Bricks for hardware safety protocols.
2. Random Midnight Restarts
If your bed turns off unexpectedly in the early morning, the culprit is often a voltage sag caused by other appliances cycling on the same residential circuit (such as a bedroom space heater, portable AC unit, or refrigerator on a shared line). When total circuit draw spikes, the Hub browns out.
3. Loose Wall Connection
Older wall outlets lose tension in their internal brass contact leaves. If the Hub’s plug slides out of the wall with minimal resistance, or sags downward under the weight of its cord, micro-arcing can occur. This creates high electrical resistance, generates localized heat, and interrupts power continuity.
Step-by-Step Power Diagnosis
Work through this checklist to isolate the electrical problem safely:
[Check 1: Direct Wall Outlet] ── Fails? ──> [Check 2: Test Different Circuit]
│ (Passes) │ (Passes)
▼ ▼
[Check 3: Inspect Power Supply Brick] [Original Circuit Overloaded/Faulty]
Step 1: Remove All Intermediate Power Strips and Smart Plugs
Bypass all surge protectors, extension cords, and smart automation plugs. Many consumer smart plugs and budget power strips are rated only for light inductive loads and cannot handle continuous draw from thermal cooling appliances without dropping voltage. Plug the Hub directly into the wall receptacle.
Step 2: Test Outlet Mechanical Grip and Voltage
- With the power plug inserted, wiggle the cord gently. If the Hub cuts power or flickers, the outlet contacts are worn and the receptacle must be replaced by a qualified electrician.
- If you have a digital multimeter, check the AC voltage at the outlet. A standard North American residential outlet should read between 114V and 126V AC. A reading that dips significantly below 110V under load indicates serious residential wiring drop.
Step 3: Test on an Isolated Electrical Circuit
Run a heavy-gauge (14 AWG or heavier) extension cord temporarily from an entirely different room—preferably a dedicated 15A or 20A circuit like a bathroom or kitchen GFCI outlet:
- If the Hub runs a full cooling cycle (-10) without pulsing or resetting on the secondary circuit, your bedroom circuit is overloaded or suffering from high-resistance line connections.
- If the Hub continues to pulse, reboot, or click on a known-good circuit, the internal power supply or brick has sustained damage. Proceed to Eight Sleep Won’t Power On? How to Test Your Power Supply to evaluate the brick’s DC output.
Protecting Your Hardware
To prevent dirty power from destroying your Hub’s sensitive microprocessors:
- Avoid Daisy-Chaining: Never plug the Hub into a power strip that also powers a CPAP machine, space heater, or television.
- Use a High-Clamping-Speed Surge Protector: If you must use a surge protector, choose a heavy-duty commercial unit with a minimum rating of 1,500 Joules and UL 1449 certification.
- Consider a Line-Interactive UPS: In areas prone to brownouts or lightning storms, an uninterruptible power supply (UPS) of 600VA or greater cleans incoming dirty power and bridges brief voltage dips, keeping your bed online without hardware resets.