I had my panel upgraded recently (eliminated old 1960 split bus). At the time the electrician told me he was required by code to replace the existing 3-wire running 4' to the basement dryer outlet with 4-wire but that he wasn't required to change the existing NEMA 10-50 receptacle, so the new ground wire would just be left disconnected inside the box. Strikes me as odd now as I'd have at least connected it to the box. Obviously my (old 1990s) dryer still has the ground/neutral jumper in place. I just bought a TIG welder (30A) which I'm going to have to run off the dryer outlet. The house only has 100A service (upgrade to 250A is not cost effective as it forces $$$ mast relo and it's only a 900 sq/ft house that we don't plan to live in much longer) so I'm not going to run a new dedicated circuit for it but it did remind me of the above conversation. I checked and it turns out he never ran new 4-wire so it's still the old 2 red + white. I know NEC code (250.140) has a specific exemption for dryers to allow bonded ground/neutral. If the dryer outlet was running off a subpanel I'd definitely be rewiring it for 4-wire but since it's running to the main panel inside of which ground/neutral are all bonded, is there any reason to run 4-wire? Clearly a welder is not a dryer but ignoring the NEC dryer exemption I can't see any reason to change to 4-wire. I called the owner of the electrical company (not the guy who did the work) and he said "he must have forgot, it's not needed"). I think he's right but wanted to check.

I am assisting a son redo a kitchen in a house that is about 50 years old and I have some questions about the electrical connection to the dishwasher and disposal. There is a two conductor cable (no ground) to a switch box. The two conductor cable is spliced into a three conductor armored cable in the switch box. The splice is soldered and taped. The armored cable connects at the bottom of the switch box and exits the wall at that point. The cable runs along the wall for 3 or 4 feet to a junction box that was mounted on the wall. A short length of armored cable runs from the junction box to the disposal and a short piece of Romex looking wire runs from the junction box to the dishwasher. He would like to clean this up as much as possible, especially the armored cable that runs along the wall. I have some thought on how to proceed; looking for input the safest, code compliant (as far as possible in a 50 year old house) way to do this. Most of my questions are about whether I can use the existing connections in the switch box or should I replace with new. Can I route the armored cable from the switch box to the junction box inside the wall? Could I use the existing solder splices? The solder is well flowed and appear to be very good. Of course I would wrap them in new tape. I am guessing I would need to drill 7/8 or 1 inch holes in the studs to route the cable thru the wall. Can I drill holes that large thru the studs? Is there something I am overlooking if I go this route? Another possibility is to replace the armored cable with new 3 conductor cable. If I do this can I use wire nuts to connect the 2 conductor cable to the 3 conductor? Can I make the connection in the switch box? We are considering replacing the junction box, where the cables are routed to the disposal and dishwasher, with a wall receptacle because it seems that new dishwashers and disposals are equipped with plugs. Any thoughts on this? Is there a common practice to make either the upper or lower receptacle switched? I apologize for being so long. Thanks for any input you can provide.