Your hand feels tingly while using a charging phone? What causes it and is it still safe?

In the interest of time, who hasn’t used their handheld device while it’s still charging? And we mean plugging your handphone, tablet or laptop into an electric socket, not a power bank. 

You might recall feeling a buzzing or tingling sensation – more so if your device is “naked” (you don’t believe in getting a case) or it has a body made of metal. It’s unnerving enough to make you wonder: Will you get electrocuted if you continue holding your gadget? Will it affect your device? Should you get an electrician to check your home? 

We find out from the experts with the “power” to decipher “watt” is going on, and whether you can minimise the strange vibrations (okay, enough puns already).

WHAT’S CAUSING THE TINGLING?

That peculiar sensation is caused by a leakage current – “a tiny, safe amount of electrical current that escapes from the charger onto the device’s metal casing”, said Lay Leong Loong, a senior lecturer from Republic Polytechnic’s School of Engineering. 

“This leakage usually comes from the electromagnetic interference (EMI) suppression components inside the charger. Among these components are the capacitors, designed to help reduce electrical noise,” Lay continued. “In ungrounded chargers, which are typically the two‑pin plugs, these capacitors can cause a very small current to be felt on the metal enclosure of your device.”

As a result, said Li Zhen, the lead science educator with Science Centre Singapore, “when you touch your mobile phone or laptop during charging, the current may flow through your body, triggering nerve endings in the skin and creating a mild buzzing or tingling feeling”.

ARE THERE DEVICES MORE LIKELY TO PRODUCE THE TINGLING SENSATION WHEN CHARGING?

“Any electronic equipment with a metallic body or casing as well as high-power adapters,” cited Boey Kai Ming, the manager of Singapore Polytechnic’s School of Electrical & Electronic Engineering.

Metal and current are, of course, self-explanatory. As for high-power adapters (they charge faster), they should be fine if they come with a functioning three-pin plug that allows the current leakage to “escape” through the third pin – and not your body, said Lay. And by “functioning”, he meant that the middle pin has to be made of metal, not plastic, as is often the case with compact travel chargers. 

The next time you travel, take note if your gadgets feel zappier than usual when they're juicing up. 

IS THERE A DANGER TO OUR HEALTH? CAN WE CONTINUE HOLDING THE DEVICE?

The tingling sensation from a charging phone or laptop is harmless leakage current, not a dangerous shock, said Boey. “The energy you feel is extremely small – hundreds of microwatts from microamp currents – compared to the actual charging process that delivers tens of watts to your phone or laptop.”

As uncomfortable as the sensation may feel to you – and it can intensify and spread throughout your body – Li added that you can “safely handle the device while charging”. 

Lay explained that “safety standards such as IEC 62368 strictly regulate the maximum allowed leakage current, keeping it well within safe levels”. “However, if you ever do experience a real shock, stop using the charger immediately.” 

An electric shock would produce “acute, sharp pain” and cause you to lose control of your muscles, “which may prevent you from releasing your grip on the electrical source”, said Li. “If the current travels through the chest, the shock may interfere with your heart's natural electrical activity, potentially triggering ventricular fibrillation or cardiac arrest.”

WHAT DOES IT MEAN FOR PEOPLE WITH MEDICAL IMPLANTS LIKE PACEMAKERS?

“In general,” said Lay, “the leaking current is not at a dangerous level to affect pacemakers.” “Modern medical devices, especially implants, are designed to withstand everyday EMI exposure, including such leakages.”

Li agreed but cautioned that “each person and device may be different, so what is safe for one pacemaker user may not be safe for another”. “The best approach is for pacemaker users to avoid touching devices that cause noticeable buzzing or tingling feeling, and talk to their heart doctor about electrical safety for their specific pacemaker type,” he said.

In addition, it pays for pacemaker users to stay a safe distance away from high-power electrical equipment, strong magnets and induction stoves as they can “create electromagnetic fields that may interfere with how the device works”, Li added.

HOW CAN WE MINIMISE THE TINGLING SENSATION?

Other than switching to a grounded, three-pin charger, Lay also suggested adding a non-conductive casing for your devices, such as those made of silicone rubber or thermoplastic polyurethane (TPU). 

“Use chargers from reputable brands or those with certifications such as UL, CE, IEC or local safety marks,” Lay suggested. “Keep charging ports clean as dust can possibly interfere with the grounding. Cleaning with an air blower or soft brush helps.”

WHEN SHOULD WE CALL FOR AN ELECTRICIAN, OR CHANGE THE CHARGER OR CABLE?

Call in an expert if the tingling sensation is unusually strong, persistent or accompanied by other issues such as overheating, sparking or inconsistent charging, advised Boey.

“An electrician should be consulted if multiple outlets in your home cause noticeable buzzing, or if you see signs of electrical problems such as tripped circuit breakers, burning smells, black spots on cables or socket outlets, or loose sockets,” said Boey.

A sure sign to change your cable or charger, he added, is if the current one is visibly damaged, feels hot, or is from a low-quality brand without safety certification. “Poor insulation or faulty design can increase leakage beyond safe limits,” Boey cautioned.

Other signs for a new cable or charger, said Li, include:

• The cable shows visible damage like worn areas, exposed wires, cracked covering or bent plugs.
• The device charges inconsistently or stops working when the cable is moved.
• The cable or charger gets very hot during normal use.
• The plug does not fit tightly into the device or falls out easily.
• Charging becomes much slower than usual.
• Sparks appear at the cable or charger when plugging in or unplugging.

You should immediately stop charging, said Lay, if you notice:

• Painful shocks
• Sparks during plugging
• Burning smell
• Smoke or unusual heat
• Signs of water exposure