I bought a house that was built in 1941. The previous owner did some work in the house, such as updated the kitchen and added on a bedroom. When he did the electrical he added copper to the existing aluminum wires among other issues. Would it be wise to get all new copper electrical wires though out the house? Mind you we do have plaster walls downstairs. If you need more info, let me know. Thanks

It certainly would be wise to replace all the aluminum cable, since it is no longer allowed for branch circuit wiring in many states. The copper-aluminum joints are a real problem, as I doubt the proper connectors and treatment were installed.

Replacing the 66 year old cable will be good also, plus updating the receptacles and switches, and possibly the service if necessary.

Any major work done will certainly add to the home's value, in addition to your piece of mind.

Plaster walls are only a minor obstacle, does take a skilled hand to cut out new box openings. I mark around the box with a pencil, then score the plaster of paris with a sharp knife, and then use a flatblade screwdriver as a chisel with my linemen pliers as a hammer using light blows to chip out the plaster. If there is the wood slats, takes a sharp keyhole saw blade, if there is the wire mesh backing, use a sharp pair of diagonal cutting pliers to cut out the mesh.

Fishing can take a bit more skill, and certainly needs knowledge of wood framing. You can check to see if there is Balloon construction, which is open bays between studs from the basement continuously open to the attic. But homes I have worked in built in 1940's did not use this framing.

Otherwise, drilling up into the bay you want wiring to run in for a switch or an outlet. I either pass a fish tape up from the basement to the new outlet opening, or drop a nylon string with a short piece of jack chain to catch with the fish tape hook and pull down into the basement.

Any ceiling outlets are certainly a challenge, and usually means cutting an notch the plaster in both the ceiling and wall to get around the wood framing that usually is in each corner where the ceiling meets the wall.

I hope this helps and answers your question.