Circuit Breakers

[Ted in NE-OH]

Does anyone know the difference between Siemens circuit breakers Q2020NC and Q2020U they appear identical but one is twice the price of the other. Any advice ?

 

[Mike(NEOhio)]

The NC designates it is a non-CTL breaker. Not exactly sure what it means but seems to limit the number of breakers that can be put in a panel. I found the paragraph below on line. I hope it helps.


For Replacement Use Only not-CTL ? The Class CTL (circuit limiting) panelboard has only been in existence for about 25 years, even though the lighting and appliance branch circuit panelboard has been in the NEC for decades. CTL panelboards have a rejection means designed to reject more than the appropriate number of circuit breakers that can be installed in the panel. The marking ?For replacement Use Only Not CTL Assemblies? means that the circuit breaker does not have CTL rejection provisions and is intended for replacement in older equipment pre-dating the CTL requirements for circuit breakers and panelboards. Circuit breakers with this designation should not be installed in a panelboard marked ?Class CTL Panelboard? since that would be a violation of the listing of the assembly [

 

[Steve@Advance]

The NC suffix means this:

Non-CTL. For replacement use only in panels manufactured
before 1968

So I would assume the U suffix is for panels after 1968?

Look closely at where the breaker stabs onto the buss bar. Probably be a different shape. CTL is a feature to prevent too many breakers from being installed in a panel and overloading the capacity.

If the lower price one will plug in, it will work.

 

[Mule Meat]

(quoted from post at 15:11:33 04/09/18) The NC designates it is a non-CTL breaker. Not exactly sure what it means but seems to limit the number of breakers that can be put in a panel.

Try to make it simple..

For example.

You have a breaker box that can hold ten 120 volt single circuit breakers.

Before 1968 (I think) you could make the same breaker box double the circuits by using CTL breakers.

You could run two circuits from one breaker using just one lug on the load center in the box.. They took up the same space as a single circuit 120 volt breaker does in a box today.

Here this may help you see how they worked.. Code violation to use them now days in breaker boxes installed after the codes came into effect.

 

[Hoenes]

Ted, just went through all this at my son's house. Siemens panel. Older panels have a limit of 20 circuits. (Count all your black connections) Will not accept tandem breakers. One clue is, if the buss bar has a notch in it, it might receive a tandem breaker. Did some research on "cheaters." People would take needle nose pliers and bust out some plastic on a breaker, and install a tandem breaker anyway. Hence the term "cheater." More than 20 circuits, not good.

 

[buickanddeere]

This is the time to toss the old undersized breaker panel and install a panel with enough full sized breaker spaces .

 

[BarnyardEngineering]

or, just double tap the breaker, which IMHO is worse than using one of these...