Double lugged or double-tapped breakers are among the most typical electrical defects we find during a standard home inspection. Double lugging is defined as two or more wires installed in a breaker rated for one wire. There are two instances where this commonly occurs; 1 on standard 120 or 240-volt breakers and 2. Less often on the main breaker. Double-lugged main breakers are the most dangerous.
Double lugged mains are a severe safety hazard. It usually involves adding a sub-panel supplied by a wire tied to the incoming service.
Without the protection of a breaker or fuse, this is very dangerous. In the example to the right, what appears to be a #10 wire which generally would be protected by a 30 amp breaker, is tied directly to the utility service. It is not protected at all, and if the circuit develops a short, the #10 wire will overheat and cause a fire. In addition, there are four wires in lugs only designed for one wire.
Double-lugged mains can easily be corrected by moving the wires for the sub-panel to an open space in the box and installing a properly sized breaker for the wire used.
How to correct a double lugged breaker
Some breakers, such as this “Square D Homeline” breaker on the left, are listed to handle two wires at one time. Note the designation of “1 AlCu and 2 Cu” indicate you may install one aluminum wire or two copper wires. You may use two copper wires as long as each wire is sized correctly and positioned under the tension clip. Unless your breakers are rated in this manner, you should not put more than one wire under the screw of the breaker.
If you have double-lugged breakers, you should employ the services of a qualified electrician. An electrician may quickly correct this problem by using a pigtail to reduce the number of wires per breaker. Adding additional breakers or using a piggyback breaker if the panel is designed to accept piggyback or tandem breakers is a better alternative.
A qualified electrician for your safety should perform all electrical work.
