Someone explain to me the difference in these breakers

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Old 08-23-13, 07:06 AM
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Someone explain to me the difference in these breakers

I was shopping for a new load center, breakers, etc yesterday and noticed Siemens breakers labeled "tandem" and "duplex" that appeared identical but had a big price difference. Both are "dual toggle in one space" types, 120V--no connecting bar, same size/shape/screw type/gauge. 2 different orange shirts in the electrical aisle couldn't tell me the difference and the load center instructions and labeling didn't tell me which to use. I verified I was looking at the correct part numbers in the correct boxes. Both fit properly in the load center I opened in the aisle.
Naturally I bought the cheaper ones--but what are the intended purposes of these?
 
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Old 08-23-13, 07:54 AM
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I was shopping for a new load center, breakers, etc yesterday and noticed Siemens breakers labeled "tandem" and "duplex" that appeared identical but had a big price difference. Both are "dual toggle in one space" types, 120V--no connecting bar, same size/shape/screw type/gauge. 2 different orange shirts in the electrical aisle couldn't tell me the difference and the load center instructions and labeling didn't tell me which to use. I verified I was looking at the correct part numbers in the correct boxes. Both fit properly in the load center I opened in the aisle.
Naturally I bought the cheaper ones--but what are the intended purposes of these?
Without the catalog numbers of each, it's difficult to know, but my best guess is that they are the same basic breaker except that one is a "CTL" breaker and the other is a "Non-CTL" breaker. The "Non-CTL" breakers have a significantly higher price; they do not have a rejection feature and are to be used for replacements only in pre-1968 loadcenters. There should have been a label on the side of them explaining this. It sounds as if you bought the correct breaker if it was for a new loadcenter.

"CTL" means Circuit Total Limiting. Today's loadcenters that accept tandem breakers will only accept the "CTL" tandems in spaces that have a notch in the bus stab. They have a little metal tab that the notch will accept. These breakers will not fit in just any space in the panel as many spaces may not have the notch that will not allow the tandem to be installed. This is how the manufacturer prevents a loadcenter from having more circuits than it was rated and listed for. On the other hand, a "Non-CTL" breaker will fit in any space because it lacks the litte metal tab rejection feature. It is a code violation to use the "Non-CTL" breakers in a modern loadcenter. Don't be too hard on the orange shirts, many inspectors don't have a clue either.
 
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Old 08-23-13, 12:08 PM
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There was different wording on the non-CTL breakers but it would only make sense if you already knew what it means.
I noticed the tab but when I pointed it out to the shirts even that didn't jog their memory. Must not get any training at all

I didn't know the tab prevented install in certain stabs (in a newer panel). That tab doesn't look like it should cost an additional $8. I didn't see any dual-choice in Eaton or GE breakers. Are there more pre-68 Siemens/ITE/Murray panels still in service than other brands?
 
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Old 08-23-13, 02:42 PM
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I think the CTL's will only fit in the top 4 slots of a panel. It may vary from panel to panel, but it has been my experience that they are limited to a few at the top.
 
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Old 08-23-13, 03:53 PM
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I think the CTL's will only fit in the top 4 slots of a panel. It may vary from panel to panel, but it has been my experience that they are limited to a few at the top.
I think Siemens, Square D and Cutler Hammer BR all have what they call 30-40 panels that accept the CTL tandems in the 5 bottom spaces on each side. There are also 16-24 panels, 20-24 panels, 8-16 panels and more.
 
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Old 08-23-13, 04:04 PM
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There was different wording on the non-CTL breakers but it would only make sense if you already knew what it means.
I noticed the tab but when I pointed it out to the shirts even that didn't jog their memory. Must not get any training at all

I didn't know the tab prevented install in certain stabs (in a newer panel). That tab doesn't look like it should cost an additional $8. I didn't see any dual-choice in Eaton or GE breakers. Are there more pre-68 Siemens/ITE/Murray panels still in service than other brands?
I believe the catalog numbers are slightly different between the CTL and Non-CTL tandem breakers. As far as training at the big box stores, I think it's mostly non-existent because they try to hire those already with qualifications. That little tab probably doesn't cost much at all, but the difference in price is probably due to the volume manufactured. Most breakers are sold through supply houses and I am sure most supply houses do know the difference and sell far more breakers for new panels than for pre-1968 panels.

You'll find Non-CTL pre-1968 replacement only breakers from Siemens/ITE/Gould, Square D QO, Eaton BR and CH and Murray as far as I know. GE never made a true tandem breaker that I recall and Square D Homeline wasn't introduced till somewhere in the late '80s.
 
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Old 08-26-13, 09:36 AM
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Thanks Joe.
The panel I bought is a 16/24. The bottom 8 stabs are slotted to accept the tandem breakers and the upper 8 stabs aren't. I think 16 circuits is plenty for my cottage so I think I'll change gears and buy all standard-width breakers and install them from the top down--leaving any unused spare stabs in the bottom positions where tandems can be used if I ever go nuts and need lots more circuits.
The directory sticker has all 8 upper stabs identified as "service disconnect"--that seems pretty excessive for residential use (maybe I don't understand the definition). Is it OK to ignore their labeling and install whatever circuits I want in those locations? I will probably organize the panel with utility-type circuits in the top positions, with wall outlets & lighting in the lower stabs.

This is a long-term project and the entire cottage will eventually be re-wired as the interior gets gutted.
 
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Old 08-26-13, 10:29 AM
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The directory sticker has all 8 upper stabs identified as "service disconnect"--that seems pretty excessive for residential use (maybe I don't understand the definition). Is it OK to ignore their labeling and install whatever circuits I want in those locations?
That's puzzling, but I am not looking at the label. You can post a picture if you'd like, but maybe I can save you the trouble. Remembering from your previous thread, your service disconnect is inside the cabin at the meter location and this is just a main lug only 16-24 single phase loadcenter installed inside at another location. You can install your circuits where ever you want, the service disconnect is your main breaker and you don't need a main breaker in this panel as this is not being used as the service entrance. Don't forget to keep neutrals and grounding conductors separated in this panel, you need a separate ground bar if one is not included. If there is a box bonding screw for the neutral bus, do not use it, throw it away.
 
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