A sub-panel is already installed on a second floor. It draws power from a 100 amp main panel downstairs. The sub-panel is feed by a 60 amp double pole breaker. The panel was installed for or by AC techs who were installing mini-split AC units. The sub-panel contains four breakers for the AC units and then one 15 amp and two 20 amp circuits were added to service general receptacles and lights on the second floor.
The house was recently bought and the new homeowners found very bad wiring such as no electrical boxes behind ceiling lights and fans, wiring duct taped together, a mixing of 12 and 14 AWG wire on the same circuit, and incidences like no neutral wire where outlets were installed.
In light of the many problems which we are knowledgeable enough to catch and understand, we would like to ask a question about the sub-panel to make sure the above description sounds on the surface like an okay set up. If so I take it that more circuits can be run from the sub-panel to add extra light and outlet receptacles in the living areas as needed. I take it that this is a proper use of the sub-panel to add circuits in addition to the AC it was put in to accommodate as long as there are slots on the panel. The homeowners are intending on upgrading the main panel to a 200 amp service soon. I take 200 amp to be the standard upgrade for homes. Are there any reasons that such an upgrade would be prohibited for local code reasons and concerns? They definitely need an upgrade since they are trying to properly wire the house to all new code requirements after the hurricane forced a gut of the whole first floor.