Tight spaces or Adding a electrical circuit

[Shorty Cox]

I keep telling myself that this stuff is not brain surgery and doing stuff to the RV is no different than doing stuff to my house, other than the RV is on wheels. However, I have come to the realization that the stuff on the RV is not made like the stuff on the house. All the RV stuff is closer together with little room to maneuver.
I would like to add two 120 electrical outlets on one circuit. I have looked and fishing the wire in the wall and to the void behind the main breaker box will be easy. There is one blank in the breaker box for an additional beaker for the circuit. The 120 breaker is a common break available at the local building supply store. In a house, one would just drill a hole in the top plate of the wall and fish the new wire in the wall and into the breaker box through a hole in the top, bottom, or sides of the box. On the RV, it appears the wire will have to enter through the back of the box. There lies the problem. I can’t determine how to access the void behind the back of the main breaker box to fish the wire into it.
Now after boring you will all this, my questions are:

Has anyone ever added a totally new circuit to the breaker box?

Is there enough “slack” in the existing wires to remove the retaining screws and slide the main breaker box out of its location a short distance to access the back?

Shorty

[Grumpy]

I've added circuits, but I have always had access either through a cabinet next door or on top. As to your question some of the wires had extra slack, others did not. The supply line is usually the one that has the least amount of slack.

If you have a cabinet on top the bottom is usually easy to remove.

[Robbbyr]

I added a new 120-volt circuit to my Seneca when I changed over from a tankless water heater to a tank-style that also has an electric heating element. I was fortunate and my Progressive Dynamics power center did have enough slack in all the wiring that I was able to pull it out far enough to work behind it after removing the (4) screws in the corners that retain the cover and the unit itself into the cabinet.

Have used the same technique to add several 12-volt circuits in my unit in unused 12-volt fuse locations. Very handy indeed.