Fluke Corp., of Everett, Wash.

The meters can fail to give an appropriate voltage reading, resulting in the operator falsely believing the electrical power is off, posing a shock, electrocution, or thermal burn hazard.

The recalled units can take longer than normal, up to 18 seconds, to display readings of AC voltages above 500 volts. Users can misinterpret the delayed reading to mean that high voltage is not present. If high voltage is present, users could be exposed to a risk of shock, electrocution, and thermal burns.