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.
Can I get and install a non-Class CTL twin
breaker like the one that was already there?
Is it safe?
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).
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?
Look for a UL sticker. If the panelboard is a CTL the UL sticker will
say "class CTL".
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
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
(Googling my model number and other avenues have not been helpful)?
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