Dec 17, 2012, 08:49 PMChuck J
I am doing some renovation in my mother's house. The house is in California and was completed in 1952. She is the original owner and no improvements/changes have been made to the wiring.
I plan on replacing some switches that no longer function optimally and have noticed that there appear to be no grounding wires (either bare or green) in the switch boxes. For example, in the master bedroom, there is a single, two-way light switch controlling a ceiling fixture. Inside the switch box there is a black wire, a white wire and a red wire. The white wire is not connected to the switch. The end of the red wire is connected to one of the terminals on the switch. The black wire is connected to the other terminal, but it is not the end of the wire. A portion of the insulation has been removed from the wire and the exposed portion is looped around the terminal. Hmmmmm.
I'm not used to seeing this as all of the homes I have owned were new construction.
First, am I to believe that in 1952 the thinking was that, since the metal shell of the switch was screwed into a metal switch box, which was connected to metal flexible conduit, which was (possibly) connected to some other metal junction box, etc., and eventually to the main panel and, finally, to ground, a separate ground wire wasn't needed? If so, is this safe? I know that current code requires a ground wire, but current electrical boxes are plastic and conduit is no longer used inside walls.
1) What do I do about grounding the new switch?
2) Assuming no ground wire anywhere in the system, will I be able to swap out her 2-prong outlets for grounded (3-prong) outlets so she will STOP using adapters and power strips with 3-prong devices?
Thanks in advance.
Dec 17, 2012, 11:25 PMJaybee
OK, first off, you said a couple of things that show that you do not know very much about household electricity. I don't say this to offend, but to caution you to please stay within the boundaries of your knowledge and expertise. Electrical is not to be messed around with as doing it wrong can hurt you or destroy your house. So please, get some help from someone with electrical knowledge.
It was common in older systems to use the metal boxes and metal conduit as a ground. It still works, but since better romex has replaced the need for in the wall conduit and then plastic boxes became the norm, a separate ground wire is used.
You cannot just replace your two-prong outlets with three-prong grounded ones without either adding a ground or putting a GFCI uphill in the circuit. However, if you do rewire and use a grounded romex, then you will have a ground and you can use the grounded outlets.
The same goes for grounding the switch. BTW, the looped black wire on the switch is a common way of supplying power tot he bottom end of the switch while also continuing that hot run to another fixture. White wires are never connected to a switch unless they are a part of a switch leg run - and in this case the white wire is coded black. the red wire is a little unusual, but since it's wiring from the 50's is explanation enough as to why it's there. Modern wiring uses the red wire (in a 3 wire with ground romex)as a second hot wire from the same switch box. Usually for something like a ceiling fan.