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Posted by The Streets on November 20, 2006, 9:13 pm
> The Streets wrote:
>> > On Sun, 19 Nov 2006 17:33:24 -0500, "The Streets"
>> >
>> >>I have a Siemens panel that in the past had a twin 20amp
>> >>breaker installed (ie. two 20 amp circuits in one space).
>> >>
>> >>Needing to free-up another space, I bought a model QT
>> >>Q2020 twin breaker.
>> >>
>> >>But -- I couldn't get it to seat in the panel.
>> >>
>> >>Further investigating revealed that the new twin breaker
>> >>is a "Class CTL" and the old twin was not.
>> >>
>> >>Questions
>> >> Can I get and install a non-Class CTL twin
>> >> breaker like the one that was already there?
>> >>
>> >> Is it safe?
>> >>
>> >>
>> > They do sell non CTL breakers "for replacelment only" but I would look
>> > closely at the label on the panel and see if there are some CTL
>> > compliant slots. You can usually swap breakers around to get to them.
>>
>> Yes - the old breaker that works is marked "for replacement only".
>>
>> I've checked the label but I don't see any mention of any slots being
>> different. In fact, I didn't see the letters "CTL" anywhere on the label
>> (though some of the print is quite small).
>
> Look for a UL sticker. If the panelboard is a CTL the UL sticker will
> say "class CTL".
>
>> We bought this house new in early 2001. It was under construction in
>> 2000, but I don't know exactly how old the panel might be. I read
>> that "Class CTL" came into existence in 2000.
>>
>> I'm guessing that my panel doesn't have any CTL compliant slots. If
>> that's the case, any harm in installing another non-CTL twin?
>
> If the panel is non-CTL you can install another non-CTL breaker.
>
> Usually a CTL panelboard will use the lower one third or so of the
> busbars in the panel for CTL breakers. For example, a 30/40 panelboard
> will have 30 regular spaces available, with the lower 10 spaces used
> for CTL tandum breakers. If the panel is indeed Class CTL and you have
> to swap breakers around to get to them, if any two circuits are sharing
> a neutral, be sure that those two circuits get landed on opposite legs
> to prevent the neutral from being overloaded.
>
> The idea is that the panelboard should have only the number of breakers
> for which it is designed. In the example of a 30/40 the max would be
> 40. No one panelboard is permitted to have more that 42 breakers due
> to possible overheating and/or nuisance tripping.
>
> Also, you may be able to find two or more general purpose circuits that
> are not heavily loaded, splice them together under a wire nut with a
> pigtail to one breaker. That would free up one breaker anyway.
OK -- Thanks!
I checked the UL label and there it was -- "Class CTL". So I have a CTL
panelboard. But the slots I've been working with so far (last 4 on the
bottom left) all seem to have a large "stab" that won't fit in my CTL
twin breaker.
So the CTL slots must be somewhere else in the panelboard -- right??
I'd rather not keep pulling breakers until I find them -- is there a better
way
(Googling my model number and other avenues have not been helpful)?
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