Greetings,

I am attempting to replace an electrical outlet in an old house in Puerto Rico. In the receptacle box, there are three wires: one white, one black, and one red. There is no green wire. Can you tell me which one is the ground wire? In the panel, there are only black and white wires.

Thanks

The ground can be the metal sheathing of the cable, if it is BX cable.

If the cable is nonmetallic sheathing, then there is no ground.
The red wire may be from a switch that controls one half of the duplex.

Note on the existing duplex there is a small metal jumper between the two silver screws, and this jumper is missing between the two brass screws, with black connected to one brass screw and the red to the other.

You need to test the voltage at that outlet. The color combination you show would indicate a 120/240 circuit. What does the outlet hole configuration look like? Are there any doubled breakers in the service panel? None of them are connected to a red wire?

Thanks for your responses. The outlet configuration is unlike anything I've seen before. There are actually two outlet boxes on the wall, one above the other. The lower outlet has two inlets. One inlet has a black and a red wire. The other inlet has the white wire. The white wire has a separate white wire spliced to it that runs up to the second outlet box. The black wire has a separate black wire spliced to it and runs into the second outlet box as well. The red wire doesn't connect to anything.

There's a double 20 amp breaker that controls the outlet boxes. There are two black wires connected to the breaker. Maybe I should get a professional on this one.