A current sensor is provided for non-invasively measuring electrical current in an electrical conductor. The current sensor includes a housing having a Hall effect sensor and circuitry for transmitting a signal indicative of the current flowing through the electrical conductor. The current sensor further includes a clamp that allows an operator to easily and repeatedly install and remove the current sensor from electrical conductors. The current sensor may also include a mu-metal device for shielding the Hall effect sensor for stray magnetic fields generated by adjacent electrical conductors.