Double tapping.....and I am not talking about playing electric guitars.

I was talking with an electrician friend of mine at a gathering this Christmas and we talked about one of the most commonly called out defects, double tapped circuit breakers, during an home inspection.  While it means "business" for him he was saying how some home inspectors don't know exactly what they are noting and cause undo concerns when everything is actually OK.  He quizzed me.  I passed.  

I am not an attorney and didn't seek the super-duper advice before writing this post, so here is my disclaimer before giving any electrical how-to information:  Don’t do any of this work if you’re not qualified.  Qualified means LICENSED and trained in electrical work. Reading this article, or watching a home improvement show, does not make you qualified.  You could be seriously hurt or killed.  This is only an  informative overview on what I have found.

DOUBLE TAPPING:
Definition:  There is no official term for this, so "double tap" is the trade slang.  Two conductors are connected under one screw or terminal inside a panel.  This could be on a circuit breaker or on a neutral bar.  I will write about neutral bars another time.  Let's just say that a  neutral bar is not a drinking establishment for both Cardinal and Cubs fans.  They should always be separate, but I digress.  


When IS a "double tap" a DEFECT? 
This is a defect when the circuit breaker isn’t designed for two conductors.  It doesn’t matter if it’s just a simple doorbell transformer wire that’s added on to the circuit breaker that already has a wire on it – the issue isn’t about the load imposed on the circuit, it’s about the physical connection of the wires.


When is "double tapping" NOT a defect? 
Double tapping is perfectly fine if the circuit breaker is designed for two conductors.  Only circuit breakers designed for two conductors will say so right on the circuit breaker, and the terminal of the circuit breaker will be designed to hold two conductors in place.  The only manufacturers  that make circuit breakers that are designed to hold two conductors are Square D (QO and HOM Series) and Cutler Hammer (CH Series).  Earlier some Square D HOM series breakers were made, but were only rated for ONE conductor.  This is a change that has been made over time.  The breaker would still say how many conductors it was rated for.  Currently General Electric (GE) and Siemens breakers are not rated for double tapping conductors.

Why is "double tapping" a problem? 
If the circuit breaker isn’t designed to hold two conductors, the conductors could come loose at some point in the future, even if they feel very tight today.  Loose conductors can lead to overheating, arcing, and possibly a fire.  This is a particular concern when two conductors that are not of equal size are landed under the screw of a breaker that IS NOT double tap rated.

Now, how can this defect be corrected?  Here is where the licensed electrician comes in and should be doing the work.
1.  Pig Tail:  
The most common repair is a pigtail.  The two conductors under the screw of the circuit breaker are disconnected from the circuit breaker and tied together with a new single conductor under a wire connector rated for the number and size of conductors.  This wire connector is commonly called a "wire nut".   Your electrician will know what to do.  I just want to point out that it is a simple repair.
2.  New Breaker:
Another remedy would be to replace the circuit breaker with a type that is designed for two conductors, as long as the panel is designed for it.  The breaker MUST be the same manufacturer as the panel.  DO NOT MIX AND MATCH BRANDS.  

Why Does This Happen:
If there are more problems going on besides just a double tap, the remedy might require more investigating and work.  I have seen this happen because of some of the following reasons.

• A homeowner finished off a basement and added a circuit wire for the new basement bedroom.  This would be a red flag to me because current requirement state that bedrooms be on Arc Fault Breakers.
  
• A homeowner added a bathroom to the home.  Bathrooms should not share a circuit breaker with anything else in the home but another bathroom.
  
• Double taps on breakers that are not rated for them just SCREAM of projects done without permits or inspections.  Usually this kind of work was done by "I have a buddy who knows electrical" folks.  

Can this be repaired?

• Add A Circuit Breaker.  If there is room in the panel, another circuit breaker can be added and the conductors split off to the two different circuit breakers.  The breakers need to be of the same series and manufacturer of panel.  NO NOT MIX and MATCH.  I have seen GE breakers stuck in Square D panels.  They do NOT fit exactly and are not rated to be used, but they do conduct electricity.  It is just that later down the road that because they don't fit exactly arcing can happen on the bus bar and damage the bar and the breaker.  This can be a fire hazard. 
• Install a tandem breaker if the panel is designed to use tandem breakers and a tandem breaker can be properly used in lieu of the wrong circuit breaker, this is another acceptable fix.  This is basically a way to install two circuit breakers in one space.  HOWEVER, the tandem breaker must be installed in the exact spots shown on the wiring schematic on the panel.  This is why electricians go to school and learn to read and know what the schematic drawing tells them.
• In cases where the panel won't accept tandem breakers or if breakers are no longer available for that panel the panel should be replaced.  A licensed electrician will be able to make that determination and give recommendations.

As stated before, this article is for education purposes only.   Do not attempt to make these repairs or diagnose electrical issues if you are not trained and licensed.  If you have questions contact your favorite home inspector or electrician.

Call Jon Bronemann Home Inspections, LLC  for your home inspection in Cedar Falls, Waterloo, Parkersburg, Charles City, Manchester, Independence, Waverly, Dike, Hudson, Jesup, Center Point, New Hampton, Oelwein, West Union, Decorah and other areas in the Cedar Valley.