i have an old sewing machine with on 2 wires (red and yellow) ?

hi i have an old sewing machine a singer 99k, em 904827. with only 2 wires a fed and a yellow. It has a foot pedal what says volts 150-250, amp 0.3. Does it need an earth on it and how can i put an earth on it when it only has 2 wires a red and a yellow. Please can anyone help. Many thanks paul.