After serious thinking Ed Pawlowski wrote :
On 12/2/2020 5:04 PM, Thomas wrote:
Bought a sous vide 800 watt cooker. Can I safely use in a 2 slot outlet?
15 amp service, older house, maybe from 1965 or so.

800 watts is pulling about 7 amps so yes, it has the capacity. Use a 3
prong adapter if the appliance has a 3 prong plug.

Yes, the kind we used to call a 'pigtail' which has a short wire and
connector to fit under the grounded faceplate center screw. I have seen
some with a 'tab' instead of a wire which functions the same *and*
makes sure the polarity is not reversed. Usually, the prongs are
different sizes to avoid this polarity problem.