Probe the existing hole with a keyhole saw to find the horizontal edges of the lath.
Old style light switch wiring.
Here s how to do it without breaking the plaster and lath.
Bring old light fixtures wired with knob and tube wiring up to code by installing an electrical box in the plaster wall.
Moiak light toggle switch retro single control switchs 6a round lamp switch mounted wall light button switch old fashioned toggle switch 6 26 6.
We have a double switch for our bathroom that controls the extractor fan left switch of 2 and the bathroom lights right switch of 2.
In box 1 disconnect a wire on the old switch and attach it to the correct terminal on the new one.
The alternate 3 way switch wiring configuration california or west coast was used as a way to wire 3 way switches and be able to supply line voltage to either switch this configuration is no longer allowed as the neutral is not present in each switch box.
Methodically dealing with one wire at a time will help avoid confusion and mistakes.
Fix old house wiring problems.
Conventional 3 way wiring is not very complex with conventional wiring the line line voltage connects to the common of one switch.
We need to replace it as its bust basically.