Non CTL vs CTL twins

[mark32]

Aside from the physical aspects that prohibit a CTL twin from being used in a non CTL panel, is there any other difference? Is the CTL twin a current limiting overcurrent device where as the non is not??

 

[jim dungar]

Aside from the physical aspects that prohibit a CTL twin from being used in a non CTL panel, is there any other difference? Is the CTL twin a current limiting overcurrent device where as the non is not??

No.

CTL stands for circuit limiting. CTL is the physical difference which prevents the installation in non-CTL locations.

 

[SEO]

Non ctl twins in ctl rated panelboards is one of the most violated actions of all.

 

[mark32]

Thank you Jim for clearing that up for me.

 

[c2500]

Non ctl twins in ctl rated panelboards is one of the most violated actions of all.

And highly encouraged...all you have to do is ask the bozo at the supply house.:roll:

 

[SAC]

Sorry to tag onto this topic, but what I don't quite grasp yet is why, for example, one can't take two 15A breakers out and put two tandem 15A breakers in (unless it's keyed for them), but you can take those same two 15A breakers out, put in a dual-pole 60A that feeds a sub, and then fill the sub with eight 15A breakers? Is it more related to the number of circuits/conductors in the panel than with the current draw? I guess I'm wondering why this particular ruling came into being?

 

[LarryFine]

Is it more related to the number of circuits/conductors in the panel than with the current draw?

That's exactly correct. You can install 80 circuits' worth of load into a panel, but you can't install 80 circuits.

Sub-panels aren't limitless. It's still up to the designer/installer to make sure that load calcs are done.

 

[SAC]

That's exactly correct. You can install 80 circuits' worth of load into a panel, but you can't install 80 circuits.

Thanks!

Anyone have pointers for a detailed "why", and what was magic about "42"? At least I think it was 42 - strangely enough, the answer to the question of life, the universe, and everything...

 

[boboelectric]

The "Magic Of 42" goes back to How many circuit breakers could a test group of firefighters could turn off while holding their breath. The average was "42".(From another seminar I attended).

 

[SAC]

The "Magic Of 42" goes back to How many circuit breakers could a test group of firefighters could turn off while holding their breath. The average was "42".(From another seminar I attended).

Wow - thanks! Now that's one I never would have guessed.

 

[LarryFine]

The "Magic Of 42" goes back to How many circuit breakers could a test group of firefighters could turn off while holding their breath. The average was "42".(From another seminar I attended).

"Now, I don't care who y'are, that's funny right there!"

It very well could be factual, but one could ask whether that's 42 circuits or 42 throws of the hand? :wink:

 

[Pierre C Belarge]

Thanks!

Anyone have pointers for a detailed "why", and what was magic about "42"? At least I think it was 42 - strangely enough, the answer to the question of life, the universe, and everything...

Mr. Anthony Montouri, an IAEI member and Inspector from NYC proposed this requirement to the NEC as a result of a large fire in a hotel in NYC. The cause was from an overloaded panel.

Here is a link of a google page with different articles relating to this topic


Unfortunately, Tony passed away a number of years ago, the year he was chosen to be the IAEI President. He was one of my favorite people in the industry, very dedicated.