Mike Dolt Enterprises
Mike Dolt Enterprises
User: Wingrider, Location: Northern Virginia
Asked on: Wednesday, April 13, 2011 at 9:28 am EDT
Answered on: Tuesday, May 14, 2024 at 4:08 am EDT
Question: I have an instance where I work of an existing 30 circuit non-CTL panel with 3 existing piggyback breakers installed. During a minor addition the contractor installed 2 more. The master electrician mentioned this may be a violation of NEC 2008 as he was called on a similar installation by a building inspector. His rejected installation was a 42 circuit panel with a main CB taking 3 slots. He was told he was limited to 3 piggybacks. This makes sense as panels are limited to 42 circuits, but when starting with a 30-circuit panel this may not be the case, as you could install 12 piggybacks prior to reaching the 42 circuit limit. Am I missing something in the code by just using this 42 circuit limit for our installation?
The NEC does not specifically limit the number of piggyback breakers that can be installed in a panel. However, there are a few factors that you need to consider: The panel's capacity
The panel must be able to safely handle the total load of all the breakers installed, including the piggyback breakers.
The breaker's ratings
The piggyback breakers must have the same amperage rating as the main breaker.*
The panel's busbar: The panel's busbar must be able to handle the additional load of the piggyback breakers.In your case, you have a 30-circuit panel with 3 existing piggyback breakers installed. The contractor has installed 2 more piggyback breakers, for a total of 5. This is still within the panel's capacity, and the breakers are all rated for the same amperage. However, you need to check the panel's busbar to make sure that it can handle the additional load.If the panel's busbar cannot handle the additional load, you will need to install a new panel.In addition, you should check with your local building inspector to see if there are any local codes that restrict the number of piggyback breakers that can be installed in a panel. Flag for review