wrote in message
oups.com...
I can't figure out what I'm doing wrong. I'm currently trying to add
an oulet for 4800 watt construction heater in my shop. I've run 10/3
wire to the outlet, added a 2-pole 30amp breaker to the sub-panel,

Some panels will only accept 2 pole breakers in certain slots. I haven't
looked into why that is, but maybe because of this.
Look to see if your box has such a condition, and if you are doing it
properly.