Reporting on Double Tapping

***Dear Barry: **The home inspectors in my area, myself among them, have an ongoing debate with local electricians. When we see two wires connected to a circuit breaker, we report this as “double-tapping.” As far as I know, only Square D brand type QO breakers are approved for use with two wires, but the electricians say it’s OK with other brands as well, such as Cutler-Hammer type CH breakers. But when I checked the Cutler-Hammer website, I found nothing about double-tapping being OK with their breakers. To make matters worse, some of the electricians in my area seem openly hostile toward home inspectors and say that we are clueless on this and other issues. Could you please provide some clarity on this point of contention? *

*Barry’s Response: *

In determining when double-tapping is or is not acceptable for a particular circuit breaker, a simple rule of thumb is to check the design of the connecting hardware at the breaker. If the hardware is specifically shaped to accommodate two separate wires, as with Square D type QO breakers, then the connection is acceptable and should not be cited as double-tapping in a home inspection report. But if the connecting hardware is a simple screw or lug, it is reasonable to assume that the manufacturer of the breaker intended there to be one wire only at the connection. In that case, double-tapping would be the proper disclosure for a home inspector. The only way to connect two circuits to a single breaker in that instance would be by indirect means. The accepted method would be to connect a short wire (known as a “pigtail”) to the breaker and to join the other end of that wire to the two circuit wires with an appropriate connector, such as a wire nut.
To avoid future disagreements over double-tapping issues, it may be necessary to change the wording of your disclosures. For example, if you find what appears to be a faulty double-tap, your report might say, “Double-tapping was observed in the main breaker panel. These breakers may not be rated for double-tapping. Therefore, further evaluation by a licensed electrician is advised.”


Question: Does everybody agree with Barries approach? If not what would you do different?

Bill *

The NEC calls for one wire per screw or lug unless otherwise labeled. The issue I come across more often is the homeowner installed double lug when they added an additional outlet circuit with no additional breaker causing an overload.

Please help me understand how double tapping causes an “overload” (assuming of course that the breaker size remains the same)?

I’ve seen people install a new circuit containing say the ten new recessed light fixtures for their new kitchen and they connect it to a breaker that is already supplying (at the allowed capacity) the living room, den and hallway and to boot they put a couple window a/c units without dedicated circuits. I never recommend the pig-tailing unless I actually know everything that is on both wires.

I never think of the breaker being overloaded (it should just trip) the real issue here is one of the mechanical/electrical connection, overheating due to improper connection (too small a contact area between conductors and breaker).



I used to think that electricians just had a thing against home inspectors…then, I read “Annex G” and it changed my whole perspective.

An electrician must know his stuff…and he must know it well enough to be able to stand up to the AHJ who is telling him the wrong thing to do.

80.29 of the NEC basically says that the electrician (and the designer) are liable for an electrical incident or accident…even if they comply with the directives of an AHJ (who, by the way, is not liable).

So…when an AHJ tells an electrician to do something and he knows it’s wrong, he has a legal duty to disobey the directives of the AHJ.

That being the case, an electrician who is certain about his work is not going to do anything differently based upon the observations/interpretations of a home inspector.

On borderline calls, I’ve learned to “Recommend an evaluation by a licensed electrician who, in turn, will repair or replace as necessary.”

My opinion as well - thus the question. With respect to the load on the circuit, it really makes little difference whether the added load is attached at the breaker or at some other point (such as a receptcle) elsewhere in the house. Assuming, for example, that #12 conductor is used on a circuit fed by a 20A breaker, the only real issue is mechanical as you have stated. The breaker will take care of the load just fine. On the other hand if the DIYer connects a #14 circuit to one leg of a 40 A 2 pole breaker, I’d have a problem with it.

Same here, in that situation the conductor has become the “fuse”



I think Barry’s response is well stated and right on. If an electrician want to assume the liability for telling the client that the double tap is safe, that is up to him.

I can agree with this up to a point. However, why call something out that is not an issue. There are not that many breakers listed for use with 2 conductors to keep track of. Why are you asking for an evaluation and costing the HO additional money. IMO it makes the HI look like they don’t know their job.

**WRONG! ** Now you are making the panel a junction box!
You can have a marrete (wire nut fot the less informed) connecting two wires only in a panel. That is so you can have a short wire reach a needed breaker. Start ading three or more wires in a marrete is out of the question.

Where is Paul Abernathy when you need him?:wink:

In some areas the ESA will allow a soft (doorbell transformer) to be under the same screw as a hard wire but technically, unless a breaker screw is designed to accept two wires, any good home inspector will advise the client a double tap is a no-no by all Electrical standards and should be assessed by a qualified electrician.

Hardly would most people consider adding a pigtail as using the panel as a junction box. Splices are allowed in panels as long as they do not exceed the cross-sectional fill area.

What happens when a panel change is done and all the conductors are too short to reach the buss or breakers? Add a whole lot of junction boxes around the panel and then take new wires into the panel?

It is true that 312.8 says “Enclosures for switches or overcurrent devices shall not be used as junction boxes, auxiliary gutters, or raceways for conductors feeding through or tapping off to other switches or overcurrent devices, unless adequate space for this purpose is provided.” and throws out some numbers but there is really no guidance about how you actually count up wire fill. The references would be in 314 but there, you don’t count any wire that does not leave the box and there is no deduction for a wire nut or other similar splicing device. All grounding wires going anywhere only count as one.
That is really no help in a panelboard enclosure if you are just talking about splices and pigtails.
Even when you add additional wires entering the box they only count as one of whatever size they are (14 = 2", 12 = 2.25" etc) and if they pass through without terminating they also count one.
I have also never seen a label in a PB enclosure that had the Cu/In or any indication about what the max wiring load would be.

One thing I will agree with Greg Fretwell on his statement and yes that is correct.

I do see that all the time espcally with upgrading the PB { panel box or breaker box } and when some of the conductors are too short I useally splice it in the box or use the Junction box and bring it down the rest for neat splice it pretty much depending on the area and how much room I have to work with it.

Now let get on other topic due the OP mention QO breakers allowed two conductors on the termation and yes it is allowed Per manufacter spec Ditto with HOMELINE SqD products as well.

The Culter-Hammer The later CH series IIRC yes they are listed for two but not the early generation CH series breakers. Ditto with the BR series

The Important part is double check the breaker manufacter they will listed what it can allowed two conductors or not.


When I did my upgrade I used a “euro block” to splice my neutrals and the inspector was fine with it. It really makes a pretty clean installation. I chose a big SqD enclosure with lots of places for supplimental ground busses so I had no problem with the grounds and the hots were long enough to get to a breaker.