Touch current and Surface devices

Touch current, or “tingle current,” may be detected by some device users when a minute, non-hazardous amount of residual electrical current passes through the user when touching a device. The sensation caused by touch current can range from a sensation of vibration, to a slight tingle or mild pinpricks.

Touch current may be detected when a device is plugged into wall (mains) power. Normally, electricity runs from the wall outlet, through the device, and back to the wall outlet in a short, closed-loop system. Touch current may be noticed if a tiny fraction of the electrical current passes through a user rather than returning to the wall outlet. Good device design and electrical safety hazard tests ensure that any touch current passing through a person is insignificant and non-hazardous.

Touch current does not occur when operating a device on battery power because the device’s power source (the battery) and its power system are contained completely inside the device.

Microsoft’s internal standards for touch current, which are stricter than the applicable regulatory standards, are designed to minimize the perception for touch current.