I’m adding a sub-panel to my house about 30 feet from the service panel. There will be two 240 volt circuits in the sub-panel. One will be a 240 v - 20 amp circuit and the other a 240v 30 amp circuit. What size breaker should I use in the service panel to power the sub-panel?
The line running from the main service panel will be a #8/3 w/ground stranded. At the subpanel one of the circuits will be powering an A/C unit with 240v which calls for a 20amp line. That 20 amp line runs about 10' from the subpanel to the A/C unit and is a #10/2 w/ground solid. The other circuit in the subpanel, will be running about 75' under the house to an outdoor sauna which requires a 240v 30amps. That line is a #10/3 w/a ground solid. I'm planning on splitting the line at the sauna to accommodate a 120volt for a light in the sauna. Here is a picture of the service panel;
The red, black pair is currently powering the A/C. They will be removed and replaced with the aforementioned 8/2 line to the subpanel.