Award Committe Question of the Week 11/29/2015

Under what conditions is it permissible to have a single terminal from a circuit breaker energize 2 wires?

Hint: looking for 3 items.

  1. Pigtail single conductor into breaker from two branch circuits
  2. Breaker listed for two conductors under lug (copper only)
  3. All conductors sized for OCPD rating

"The only time two wires can be installed under a single screw or lug is when the terminal is identified for this purpose. Circuit breakers rated not more than 30 amperes are often identified for the termination of two conductors. This can be verified by reviewing the circuit breaker manufacture’s catalog.

Neutral and equipment grounding lugs for panelboards are often suitable for two and sometimes three wires. This information is contained on the label affixed within the panelboard or on the packing container of the equipment ground lug. Often the instructions will identify the number of conductors, the size of the conductors, the conductor material, as well as the torque requirements."

looking for a bit more still… very close though…

The only other fix is to add a breaker, but that would not be an option for the original question.

Addition to post #3
“Split-bolt lugs… are generally only rated for two conductors, but some manufacturers list these devices for three wires”

In my area city building code inspector will not allow it regardless what the manufacturer says.

No one can override the manufacturer.

1 If you want to connect two load wires to a breaker, you must use a breaker that is “labeled and listed” for two wires.
2 Otherwise a wirenut connecting two circuits to a pigtail should be ok, as it is not a “circuit passing through” which would fall under the prohibited junction box usage. 3.You can install two wires under a single screw or lug is when you identify the terminal for this purpose.


Any city can enforce stricter building codes. In the case of the breaker limiting one wire does not violate the manufacturer’s recommendations. Some breakers allow two wires, but only using one does not override the allowable maximum of two wires. If the city allowed three wires when the manufacturer’s label only allowed two would be overriding the manufacturer and is not enforceable.

No they can’t when it comes to this.! manufacturer’s don’t give recommendations. There story are the facts. Don’t be disillusioned .
They have been UL tested.

I guess Chicago can’t require conduit over NM wiring then. Better call them and let them know.


Would a door bell transformer be #3

#1 Split Bolt lugs
#2 Neutral and equipment grounding lugs for panelboards*
#3 Only time it can be installed under a single screw is when the terminal is identified for this purpose and usually OCPD not rated for more than 30A

Yes! He is correct . I misunderstood what he was getting at.

Someone should be able to get this

  • The OCD is listed by the manufacturer for two conductors
  • The conductors are copper, the same gauge and appropriately sized (i.e., the conductors comply with the manufacturer’s listing)
  • The circuits are each labeled and the combined load does not exceed the OCD rating

Pigtail single conductor into breaker from two branch circuits.

The breaker is listed for two conductors.

Use of a multi tap lug terminal kit.