I had some minor work done and the electrician pointed out some upgrades that might be a good idea. Essentially, the entire house could stand to be rewired--it was built in 1947. I'm thinking of only doing the basement. However, it is not really necessary. It's just old wiring and some of the circuits supply more than one room. For example, if I want to turn the electricity off in the basement for some reason, half of my kitchen will be without electricity as well. It's inconvenient, but not necessarily dangerous. My concern is, that if I have the basement rewired, that will lead to having to rewire the rest of the house. I've lived with it this way for 11 years. So, I'm wondering if I should just leave it, to avoid the possibility of then being obligated to do the rest of the house. Any thoughts?
My house was built in 1940 and we are gradually rewiring the whole house. Here are the reasons why:
- aluminum wires: most of the original wiring was aluminum which is not as safe as copper. A particular problem is that there are many devices (outlets, lights, etc) that are rated for copper but connected to aluminum wires. This is dangerous.
- equipment ground: most outlets are not grounded while many electronics require a ground (i.e. three pronged plugs). New circuits are all grounded.
- buried junction boxes: in doing other renovations we discovered junction boxes (boxes in which wires are connected) buried under plaster or otherwise inaccessible. Maybe 80 years ago that was OK but it is not up to code today.
- other safety concerns: We've noticed unprotected wires, NM cables running outside (no conduit), etc.
- high draw devices: we are installing air conditioners in each of the rooms and these require dedicated circuits. I wouldn't have used hair dryer in the bathroom with the old wiring (safety concern).
When determining the order of rewiring, we have two criteria:
- address the most urgent safety issues first: having a usable, GFCI outlet in the bathroom, for example.
- address the wiring that can be done together: we have our kitchen ceiling down at the moment so we've used the opportunity to run some wiring for second floor outlets.
You might want to have an inspection / evaluation completed and then assess what parts of the system should be rewired and in what order.
In modern day, there are fantastic protective circuits available. Both AFCI (and to a lesser extent, GFCI) are practically miracle cures for a huge variety of wiring hazards.
I don't mean GFCI like the goofy receptacles with a test button. I mean GFCI as a "zone of protection".
Securing your house could be as easy as installing dual-mode GFCI/AFCI breakers. I would buy 1 or 2, and install one circuit at a time. After a few days if it doesn't have any problems, install another and buy another. Sometimes there are problems with crossed neutrals, or intentionally crossed neutrals in intentional "multi-wire branch circuits" (MWBC). In those cases, a 1-pole GFCI will not work. If it doesn't, roll it back to plain breaker and mark it for troubleshooting later, and move the AFCI/GFCI to the next circuit.
After a few weeks your panel should be pretty full of AFCI/GFCIs with a few lingering trouble spots. Then, right at the panel, hunt for shared neutrals or hot-ground leakage (I won't get into the gory details of that, but you can do it right at the panel). Mainly you are looking for a) exactly 2 hots that b) share a cable with 1 neutral also -- those are MWBCs. The best choice for an MWBC is a 2-pole AFCI/GFCI, but it will also work to use 2 newer AFCIs (the type that don't need the neutral wire) that are handle-tied.
With any remaining circuits that share neutrals or trip GFCIs, you need to start following wires and opening up junction boxes because there is a problem.