Siemens twin breakers, CTL vs NONCTL?

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sw_ross

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Can someone explain when to use each one?
I know (learned today!) that the NONCTL has a deeper throat/notch (?) to fit on the tabs of an older Gould panel when the shallower notch on the CTL breaker couldn't seat properly.
Not really sure what CTL stands for?
Do other brands of panels have this marking on their twins?
Thanks!
 
Its to limit the number of breakers that can be installed. Perhaps not an issue as we no longer have the 42 circuit limit.
 
CTL=circuit total limited

panels listed as CTL only allow for so many breakers to be installed in them either with standard size breakers and/or have bus bars that also allow twins (of the CTL type which do not have as long of notch in the back so it will slip over the notched bus.) This is the listed use of the product. So that it’s max allowable circuits can be maintained.

Now if one wants to add a circuit to a CTL panel and its already maxed out with standard and/or twin breakers the only part of the bus bar left is a section with non-notched bus bar made only to accept standard size breakers so one would have to use a twin breaker listed as non-CTL so it’s design has the deeper notch to fit over the bus.

CTL breaker = short notch
Non-CTL breaker = long notch
 
tom baker said:
Its to limit the number of breakers that can be installed. Perhaps not an issue as we no longer have the 42 circuit limit.
Click to expand...

But even though the NEC has changed, the listing instructions for the panelboard have not changed retroactively, so there could still be a concern.



To expand on Tom's description, the requirement for a deeper notch on the breaker material allows the panel manufacturer to configure a limited number of positions to accept tandems and the other positions to reject them. The idea is that twice the unrestricted slots plus the restricted slots adds up to 42 or fewer, but you can still use a limited number of tandems.
The non-CTL breakers were produced to allow a greater use of tandems once the 42 circuit limit was removed from the NEC, among other things.

There is still a maximum current per stab/position that limits the sizes available in tandems.
 
Santa49

Santa49

I must be missing something on this. Several years ago when we bought a 20/24 circuit breaker box I would have 20 full spaces to fill or I would have 16 full spaces and 4 tandem spaces.

The majority of my projects have been with SQD or CH. (But not limited to that, by any means) At that time I don't recall ever chosing between CTL or NONCTL.

As time went on I noticed that the notch on the buss bars showed up and the notches and tabs at the base of breaker that fastened it to the panel showed up.

The way that was explained to me was that they(I don't who they is) realized that we were overfilling the capacity of the panel more than the manufacturer intended . Like maybe making a 40 circuit panel out of a 20 circuit panel.

I think, now (today)the 20/24 circuit boxes are rated(listed) for 20 full sized breakers or 16 full sized and 4 tandem breakers using only CTL rated breakers.

The NONCTL rated breakers are to be used for replacement purposes on existing installations only.

This should hold true on any brand or size of panels.

Somebody please jump in on this and correct me.
 
NON-CTL

NON-CTL

From what I learned today, if I had to go to a house that needed to add a circuit and the panel is mostly full I'll definitely bring a non-ctl breaker even if it's twice as expensive.

Luckily I brought 1 of each since I didn't really know what the difference was.
 
GoldDigger said:
The non-CTL breakers were produced to allow a greater use of tandems once the 42 circuit limit was removed from the NEC, among other things.
Click to expand...
This statement gives the impression that CTL tandem breakers have been around longer, but I believe the opposite is true.
 
If you went to the jobsite and had a 30 circuit panel would it be code compliant to add a tandem breaker to make it a 31 circuit panel?
 
Santa49 said:
At that time I don't recall ever chosing between CTL or NONCTL.
Click to expand...

CTL and Non-CTL breakers have been around since roughly the mid-60's.
We used to call the Non-CTL ones 'cheater' breakers. Local wholesalers only stocked the Non-CTL so many electricians never even knew there was an option or a price difference.
 
Santa49 said:
I must be missing something on this. Several years ago when we bought a 20/24 circuit breaker box I would have 20 full spaces to fill or I would have 16 full spaces and 4 tandem spaces.

The majority of my projects have been with SQD or CH. (But not limited to that, by any means) At that time I don't recall ever chosing between CTL or NONCTL.

As time went on I noticed that the notch on the buss bars showed up and the notches and tabs at the base of breaker that fastened it to the panel showed up.

The way that was explained to me was that they(I don't who they is) realized that we were overfilling the capacity of the panel more than the manufacturer intended . Like maybe making a 40 circuit panel out of a 20 circuit panel.

I think, now (today)the 20/24 circuit boxes are rated(listed) for 20 full sized breakers or 16 full sized and 4 tandem breakers using only CTL rated breakers.

The NONCTL rated breakers are to be used for replacement purposes on existing installations only.

This should hold true on any brand or size of panels.

Somebody please jump in on this and correct me.
Click to expand...
I agree with what Jim said, you probably only had seen non CTL tandems back when you thought there was only one type. Non CTL breakers fit in any space in any panel (of which they are designed to fit anyway) Panels designed to accept CTL breakers have rejection features that only allow CTL tandems to be installed where the manufacturer intended. Now that the 42 circuit rule is gone you are starting to find some panels that accept CTL tandems in every position.

Non CTL tandems were intended as replacements only in older non CTL panels. But they get used a lot anyway as a "cheater"

Santa49 said:
If you went to the jobsite and had a 30 circuit panel would it be code compliant to add a tandem breaker to make it a 31 circuit panel?
Click to expand...
See instructions on the panel label. If you don't want to do that then try plugging on a CTL tandem, if it won't fit because of "rejection features" then it isn't intended to fit that position. QO usually needs a notch in the foot rail to accept CTL, most others have a notch in the bus where CTL tandems are allowed. GE has a different type of bus configuration to accept those "half width" type breakers where they intended you to be able to use them.
 
Could someone help me find the Code article that would permit installing a tandem breaker in an existing 30 circuit panel that is listed fo 30 circuits, but I need just one more circuit?
 
Santa49 said:
Could someone help me find the Code article that would permit installing a tandem breaker in an existing 30 circuit panel that is listed fo 30 circuits, but I need just one more circuit?
Click to expand...

No code section for that exists. You may only install as many or types of breakers as the panel is listed for. That info is usually found on the label.

If not, one may look up the make and model and find out.
 
Santa49 said:
Could someone help me find the Code article that would permit installing a tandem breaker in an existing 30 circuit panel that is listed fo 30 circuits, but I need just one more circuit?
Click to expand...
110.3(B) and following instructions for the panel in question is what will or will not allow using tandem in that panel.
 
Santa49 said:
Could someone help me find the Code article that would permit installing a tandem breaker in an existing 30 circuit panel that is listed fo 30 circuits, but I need just one more circuit?
Click to expand...

Is this resi? If so I would probably just find two general use circuits and double them up. If this is a typical resi situation, half or more of those breakers only have a few amps on them. If you have 30 spaces used, pretty good chance that place wasn't wired code minimum. If its commercial, prob still a good chance theres some lightly loaded stuff in there, but this might not be the best approach unless you know what stuff is and/or its labeled well.
 
So this bite me in the butt today.

Installing a two pole circuit in a full SQD panel. New house, new panel, installing two tandems to make room. Assumed they had gotten over the CTL/non-CTL thing on new panels especially since there were already three tandems in the panel. I start popping out breakers to combine them and my CTL tandems won't fit. I pull out the top six breakers looking for the CTL tandem allowed spaces and they don't fit. I look at the tandems already installed in the panel and they are CTLs that have been illegally modified.

I put everything back together and tell the HO I need to order some "special" (non-CTL) breakers to make this work. Upon doing some research to order said breakers I find that the CTL allowed spaces are at the BOTTOM of the panel! What The! Why didn't I check the bottom. I've just always seen the tandems at the top. Duh!
 
electrofelon said:
Is this resi? If so I would probably just find two general use circuits and double them up. If this is a typical resi situation, half or more of those breakers only have a few amps on them. If you have 30 spaces used, pretty good chance that place wasn't wired code minimum. If its commercial, prob still a good chance theres some lightly loaded stuff in there, but this might not be the best approach unless you know what stuff is and/or its labeled well.
Click to expand...
You're a bad, bad, kitty:D
 
Coppersmith said:
So this bite me in the butt today.

Installing a two pole circuit in a full SQD panel. New house, new panel, installing two tandems to make room. Assumed they had gotten over the CTL/non-CTL thing on new panels especially since there were already three tandems in the panel. I start popping out breakers to combine them and my CTL tandems won't fit. I pull out the top six breakers looking for the CTL tandem allowed spaces and they don't fit. I look at the tandems already installed in the panel and they are CTLs that have been illegally modified.

I put everything back together and tell the HO I need to order some "special" (non-CTL) breakers to make this work. Upon doing some research to order said breakers I find that the CTL allowed spaces are at the BOTTOM of the panel! What The! Why didn't I check the bottom. I've just always seen the tandems at the top. Duh!
Click to expand...
Square D has always put the tandem allowed spaces at the end away from the main lugs/breaker. Newer panels don't have a top or a bottom as they can be oriented either way.
 
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