What is a “double tapped” circuit breaker?

A double tapped circuit breaker, commonly referred to as a “double tap” is an electrical defect inside an electrical panel.

Double taps are only visible when the panel cover is removed and are one of the most common problems in an electrical panel. Double taps are a fire hazard, and therefore should be addressed as a homeowner becomes aware of them.

A double tap occurs when two wires are connected to a single circuit breaker that is only engineered to accept one wire (see photo below).
This is a defect because two wires in a single breaker may not be properly tightened to the breaker and loose wires have the potential to cause overheating and arcing.
 
  

Are double taps expensive or difficult to fix?

While this is a common defect, fortunately it is relatively inexpensive and easy to fix in the majority of situations.
The most common repair is to simply add another circuit breaker to the panel and connecting one of the wires to it. Occasionally there is not room for another breaker, which may be why the double tap exists to begin with. When this occurs there are still options to remedy which a licensed electrician can asses.
Square D and Cutler Hammer both manufacture breakers that are rated to accept two wires (double taps). When two wires are allowed a tiny graphic of two wires will be visible at the front or side of the breaker.
square d double tap breakers
While double taps into a breaker are the most common way this wiring error is made, “triple taps” ( three wires into a single breaker) and double taps  at the  main service lugs (sometimes called a top tap) are also regularly seen.
triple tapdouble tap at main lugs
Homeowners should always hire a licensed electrician to work on electrical components in their home but especially any work in the electric panel due to the safety risks involved.