Before you embark on that DIY wiring project you're considering, ask yourself it that's really how you want to die.

“When homeowners start messing around with electrical circuits and running cables, there are two likely outcomes, and both are lethal: electrical shock and fire,” says veteran do-it-yourselfer Joe Truini in Today’s Homeowner magazine. He goes on to recount seeing an unsettling photo from an Illinois home inspector of one DIY project: A wall switch mounted inside a shower. “It’s a wonder no one was fried,” Truini concludes.

It shouldn’t come as a shock that you should hire a certified electrician when you need wiring repairs. Electricians are trained to do the job without electrocuting themselves or leaving a potential fire hazard lurking in your walls.

Think you're smart enough to do your own wiring? Take a peek at some of the problems electricians say they routinely encounter when a do-it-yourselfer tries to do it himself.

Related: 8 Signs You May Have a Problem with Your Home Wiring

Electrical tape: The duct tape of wiring DIYers

In Lexington, Kentucky, electrician Nick Maxey encounters a lot of black electrical tape wrapped around do-it-yourselfer wiring jobs when he’s called to fix a problem. This has been going on for the 15 years he's owned Threewire Electric. It’s such a common problem that Maxey wonders if people really believe electrical tape is a safe solution for home wiring. It isn’t.

“I’ve seen a lot of handyman jobs where a lot of electrical tape was used where it shouldn’t be,” Maxey says. “Twisting wires together and using lots of tape to hold them. This often leads to bad connections that can become potential fire hazards. Any type of loose or failed connection typically generates heat.”

Related: Not Too Bright: Are You Using the Wrong Bulb for that Lamp?

Getting your "wires" crossed 

Bob Wagner owns Express Electrical Service in Raleigh, North Carolina. In his 30 years in business, one of the most unusual things he’s seen was a homeowner’s telephone wire snafu.

“This guy had all his switches and outlets wired with telephone wire,” Wagner says. “That wasn’t good.” This may win the award for understatement, as Wagner went on to explain that the gauge of telephone wire is too small — only half of what’s needed — to handle the standard 120 volts needed for a home in the United States. The regular flow of current can overheat the wire, melt the insulation and cause a home fire.

Ceiling fan fails 

Although installing a ceiling fan might seem simple enough, Wagner has had many frantic calls from homeowners who tried this DIY project. “We hear from them when the fan comes crashing down on the dining room table, or it’s dangling by the wires from the ceiling,” he says.

Would that pass inspection?

”More often, we’ll have people turning an attic into a bonus room and they do all the wiring themselves, but never get it inspected,” says Wagner. “Then when they go to sell the house, they don’t have the proper wiring, the proper fixtures. One job we just did, it cost the homeowner $7,000 to redo a room because he didn’t hire an electrician. Worse case, you have to tear out all the drywall and replace the wiring from scratch.”

Attic hazards and hidden junction boxes

Greg Green is the owner of Davis & Green Electrical in Richmond, Virginia. “We see a lot of problems with single-strand conductors run in an attic” — a dangerous shock hazard — “when the appropriate wiring method would be metallic sheath cable,” he says.

“A lot of times we see floating junction boxes with no support,” Green adds. “Any wiring that rubs on the box can wear it out and make a spark. We see a lot of homeowners who cover up junction boxes. Then when there’s a problem, you’ve got a mystery box and can’t find it.”

Forgetting the GFI (a "shocking" mistake)

Dangerous mistakes typically stem from a lack of knowledge, Green says. “So many times we’ll see a homeowner who put an outlet outside. You would think most of the population would be educated enough to know that an outdoor outlet needs a ground-fault interrupter button that will trip the outlet if there’s any water” — the lack of which may cause your home to burn to the ground.

When a little knowledge is a costly, dangerous thing

Phillip Solomon, a San Diego electrician with 32 years of experience, says it’s almost always less expensive to call an electrician first than pay to have him fix what somebody else worked on.

Homeowners “get in over their head or can’t make sense of the wiring, or they’ll get something apart and can’t get it back together. If there are multiple colored wires, they run into trouble; they start tripping the breakers and things aren’t working. We hear from people who say they went on the Internet or watched a video to learn how to do something, but it didn’t turn out quite right.”

“Most people have to go through that experience to appreciate the value of a good tradesperson,” he says. “You’re trying to save a dollar but end up spending $100.”

The benefits of hiring an electrician include getting a written warranty on the work. Most licensed electricians are also bonded and insured for any problems that might arise later. “From a permitting standpoint, if the work was done without a permit, there’s no mortgage company that’s going to write a loan on a house with an addition that’s never had an inspection,” Green says.

Related: Innocent-Seeming Habits That Put Your Home at Risk

Steve Evans, MA, is an award-winning journalist with more than 20 years experience in daily news, investigative, health and business journalism. Among other jobs, he has served as managing editor of the Central Virginia Newspaper Group, as a senior writer for SNL Financial and as a staff writer for The Progress Index and the Richmond Times-Dispatch.