42 ckt limit

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jmellc

Senior Member
Location
Durham, NC
Occupation
Facility Maintenance Tech. Licensed Electrician
Someone refresh my memory. Was it 2008 or 2011 that did away with the 42 circuit limit for panels? I think 2008 but can't locate it at the moment. Question has come up with a friend, looking at a 40 ckt QO panel with 3 tandem breakers. I think it's ok, as the limit has been lifted. Home inspector wrote it up as needing correction.

Thanks for feedback.
 

jmellc

Senior Member
Location
Durham, NC
Occupation
Facility Maintenance Tech. Licensed Electrician
The panel is probably not listed for use with tandems, even though the limit has been lifted.

Present code says a panel should prevent use of tandems if not listed or labeled for them. I guess that did not apply in past years? I guess we are still bound by the wording on the panel itself?
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
There are two types of tandem breakers, ctl and non ctl. One will work in a rejection type panel ( made for the older panels) but not listed for it and the other is made for the newer panels, and will not fit in the rejection rail.
 

George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
The HI is probably correct. If my dad can get a QO breaker into a homeline panel, then CTL is not the obstacle the factory wishes it was. I'll bet you find that the panel has too many breakers in it.
 

John120/240

Senior Member
Location
Olathe, Kansas
Someone refresh my memory. Was it 2008 or 2011 that did away with the 42 circuit limit for panels? I think 2008 but can't locate it at the moment. Question has come up with a friend, looking at a 40 ckt QO panel with 3 tandem breakers. I think it's ok, as the limit has been lifted. Home inspector wrote it up as needing correction.

Thanks for feedback.

So what is the correct fix for this situation ? Change the tandems to one full size breaker,

add a two pole to feed the sub panel, then have five breakers in the sub panel. Technically I

understand this would be the correct fix. I'm all for the work but is the current setup

doomed for failure ? Yes I know, how many tandems is too many before you do the fix ?
 

George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
I'd say you could probably find a few circuits to combine in a typical residential panel without overloading them. 10 wirenuts and it's done.

Steve, I have a bad picture of it somewhere, I'll try to dig it up. He wondered why the lights flickered when he walked past the panel. :)
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
I have never seen a QO ctl breaker other than in a catalog. The supply houses and home improvement stores around here only stock the non-ctl versions of the piggy back breakers.
 

kwired

Electron manager
Location
NE Nebraska
I have never seen a QO ctl breaker other than in a catalog. The supply houses and home improvement stores around here only stock the non-ctl versions of the piggy back breakers.

That probably means there is more demand for them and they are being installed in places where they likely were not intended to be installed.

The CTL versions around here do cost less than the non CTL. If you were to buy a panel intending to install tandems you are much better off to purchase a panel with more spaces to begin with and use standard breakers. - Now with the need for AFCI's you are seeing larger panels anyway as tandems are just out of the question to more degree.
 
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