I have done posts in the past about improper wiring to disposals. It is a defect that I see repeated in home after home.
Anyone can go to the Big Orange Tool Box or similar types of home maintenance stores and buy a garbage disposal. How difficult can it be to take the old one out and put the new one in?
Well it actually isn’t that difficult and the part of the installation that I find wrong the most is the electrical connections—arguably the most important part. The wiring is done wrong the most on those units that do not have a plug-in type cord, and instead the disposal is “hard-wired.” “Hard-wired” means is that the unit can’t be unplugged—-and instead is wired continuously all the way to the breaker panel. When wired this way it is important that the wire that runs from the wall to the disposal be of proper type and be properly protected from mechanical damage—typically in flexible metal conduit from the connection at the wall.
Installers that don’t know proper connection methods (aren’t electricians) sometimes just hook the wire that comes through the wall directly to the disposal. In this picture we can see where the wires have been run inside flexible conduit but the conduit is badly damaged at the wall in the background and is not connected properly to the disposal in the foreground. Notice also that the ground wire is not connected to the disposal. It is important for disposals to be properly grounded to prevent persons contacting the disposal from being the shortest path to ground in the event of a short in the unit.

In this case it would seem that the installer knew the wiring should be in conduit but they just didn’t know how to make the connections at the ends of the conduit. Closer to I “cantduit” than conduit.
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Charles Buell, Seattle Home Inspector
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Everyone can avoid disposal problems by disposing of them (put disposal in trash compactor and take both to the recycling station). Moving food waste by hand to a recycling bin adds to the compost supply, not to sewerage/rats-in-pipes problems. It also saves resources which go into a useless gadget left over from the 50’s. Further is saves electricity, which can be better used to charge your car. And lastly, it keeps you from having the conversation when the inspector discloses the bad wiring when you buy or sell a home.
Glenn that is such great advice and I concur 100%. I have never owned one and would never own one for all the reasons you state.