Homeowners sometimes think they are wise in doing electrical work themselves, and saving all that money that the "professional" would have charged them. Well, that may be the case... IF THEY DO IT RIGHT!
But, unfortunately, I most frequently come across what I call "Electrical Spaghetti" served up by the homeowner.
Here we have loose "Spaghetti" going everywhere. Homeowner, or amateur wiring is usually pretty easy to spot. The most common thing, is that none of the wiring is neat, and almost never stapled or secured properly to the framing. The wires at the top of this box should be fastened (staples) securely to the wood to conform to national code requirements.
Here is the other side of the wall, where wires are run Under joists, loose loops, and loosley run down the wall.
This is the homeowners idea of wiring the hot water heater. The wire connections are exposed, and the wire is run loosely over the water heater, not secured, or in conduit.
The yellow, looped wire is providing power to the relatively new furnace unit.("Spaghetti, anyone?")
Even when they almost got it right, they forgot the simple addition of a cover over the junction box.
Exposed wiring under kitchen sink= "bad electrical jujuj" .
The homeowner figured he saved about $1500 in doing all of this himself (and he did.. for about 6 months). But now that he is selling his house, the lowest estimate that came in to "fix" all of the things he did...
was $2350. I don't think he thinks he saved money ... any more.