tandem breakers

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gimpyfac

Member
Do any of the local areas limit the use of tandem breakers in new construction, to the point where they don't want them used in a new panel. What do AHJ's out there think and what do you think when the panel is full,should space be made available for future expansion.
 
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hurk27

Senior Member
Location
Portage, Indiana NEC: 2008
Re: tandem breakers

Tandem breakers are allowed even in new construction. But are often not installed acording to the panel listing. most manufactures only allow them in certian spaces in the panel if they are allowed at all. these type of tandem breakers has to be type CTL not NC. NC tandems are only allowed for replacement in older panels that list them on the panel label and can not be installed in newer CTL panels.

Look at this thread for more info:
Topic: TANDEM OR CHEATER BREAKERS
 
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pierre

Senior Member
Location
Westchester County, New York
Re: tandem breakers

From the NEC Handbook. "Class CTL panelboards incorporate physical features that, in conjunction with the physical size, configuration, or other means provided in Class CTL ciruit breakers, fuseholders, or fusible switches, are designed to prevent the installation of more overcurrent protective poles than the mumber for which the panelboard is designed and rated."

I have a Murray Type MH-T double 20 amp breaker that fits in a single position (one individual phase slot) of a panel, and it has a large label (no glasses necessary to read it :D ) on the side that says 'FOR REPLACEMENT USE ONLY. NOT FOR CTL ASSEMBLIES'. I also have a "two 1 pole" Sq D breaker that has the same large label on the side.

If you have a panel enclosure that is listed as CTL, these circuit breakers (even though they can be made to fit) are not permitted in the enclosure.

Pierre
 
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a.wayne3@verizon.net

Guest
Re: tandem breakers

Pierre (even though they can be made to fit) Isn`t that a hacksaw cutting the tab out of the breaker..... :D
 
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hurk27

Senior Member
Location
Portage, Indiana NEC: 2008
Re: tandem breakers

Allen
NC type tandems will fit any where a regular breaker will fit. They are made to replace tandems that were manufactured before the CTL requirment built into the panels by UL.
There is nothing you have to cut to make them fit as they will go right in. So this is the reason for the warnning label. and they are not allowed to be used in any other panel. They are for replacement only. CTL type breakers on the other hand would have to be modified to fit in a regular breaker space. This is also not allowed.
 
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a.wayne3@verizon.net

Guest
Re: tandem breakers

Hurk27 thanks for the knowledge...That`s why I love this site :D
 
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