On Monday, May 28, 2018 at 11:29:56 AM UTC-4, wrote:
On Mon, 28 May 2018 11:14:50 -0400, wrote:

On Mon, 28 May 2018 07:20:42 -0700 (PDT), condo owner
wrote:

I turned off ALL circuit breakers in the panel.

I then pulled out the duplex receptacle from the electrical box in my garage and removed the wires.

I then attached the black, white and ground wires to a new duplex receptacle with two USB ports.

I was shocked by another white electrical wire in the box. Why wasn't that circuit controlled by a circuit breaker in the panel? Should the white wire have power?

Trader is right, you may have a problem with the building grounding or
neutral wiring. Theoretically if the last time the neutral was
grounded was at the service disconnect and it goes unshared from there
to your unit, there should be no voltage there with all of your
breakers off but if there was some connection of neutrals between
units down stream of the service disconnect you can see a voltage
there. It should be very small tho. You might also have the problem
that "ground" in your panel may not be ground everywhere. There are
typically voltage gradients between what we call ground in different
places.

It could just be that the neutral is sharing two hots.
If you get between two white wires you complete the circuit.
Was there a red wire coming in and leaving the box?

But he has the disconnect open, so that neutral would not only be
sharing a hot which is a code violation, but it would also be sharing
a neighbor's hot on a different service.