Quick Answer: What Does No Ctl Mean?

CTL breakers have a rejection feature on the bus connection side of the breaker. This prevents them from being used in certain areas of a loadcenter. Non-CTL breakers do not have this rejection feature and will fit in any space in the loadcenter.

What does CTL mean in breakers?

Panelboards must follow UL Standard 67, which requires all lighting and appliance panelboards to be Class CTL ( Circuit Total Limiting ).

How do I know if I have CTL panels?

To determine if the panel will accept CTL or Non-CTL duplex/quadplex breakers is by taking a look at the bus. The bus will either be notched and shaped like a U or it will be unnotched and solid.

What is CTL load center?

Class CTL (Circuit Total Limiting) is a classification of load centers from the 1965 National Electrical Code (NEC). In general, QOT (e.g., QOT2020) are the new version of tandem breakers designed to be used in present class CTL QO load centers.

What is a non current limiting circuit breaker?

Non-circuit limiting is an older technique of electrical wiring. In a non-circuit limiting system, no allowances are made to limit the amount of current that flows through the circuit. Because of this, the circuit has no set maximum current, and spikes can occur in the voltage flowing through the circuit.

What is a CTL electrical panel?

Circuit total limitation (CTL) is one of the present-day standards for electrical panels sold in the United States according to the National Electrical Code. This standard requires an electrical panel to provide a physical mechanism to prevent installing more circuit breakers than it was designed for.

What is the difference between CL and NCL breaker?

CL or CTL panels and breakers have been required since 1965. They have rejection clips to prevent tandems or quads from being installed in some panels, or in some spaces within some panels. NCL or Non CTL breakers are made for replacement use in pre 1965 panels.

What is the difference between CTL and non-CTL breakers?

CTL stands for circuit total limitation. This normally is applied to the “twin” or 2 in 1 breakers used in residential loadcenters. CTL breakers have a rejection feature on the bus connection side of the breaker. Non-CTL breakers do not have this rejection feature and will fit in any space in the loadcenter.

What is the 6 throw rule?

The “six breaker throw rule” is a requirement in the National Electrical Code [NEC 230.71(A)]) that a service must have have a main disconnect that shuts off all power and it cannot take more than six switch throws to do it. The main disconnect or disconnects also must be clearly marked, as in the photo above.

What is a rejection tab on a breaker?

The rejection tabes are in place to prevent you from putting those breakers into a “non-CTL” panelboard. Doing so can/would exceed the maximum number of circuits or poles a panel is designed to accept.

Are tandem circuit breakers safe?

Tandem breakers are safe and legal to use only when the panel is designed for them and only in the slots that accept tandem breakers. In other words, just because there is space for more breakers doesn’t mean the panel can safely handle the extra load of new breakers.

Are slimline breakers safe?

Fortunately, despite that moniker, tandem circuit breakers are completely safe to use provided your panelboard was meant to house them and that you install them in the correct locations.

Does the NEC allow tandem breakers?

Technically, NEC 2020 does not outlaw any tandem or quad breaker.

What is non current-limiting fuse?

For a fuse to be considered “current-limiting”, it must interrupt the circuit within 180 electrical degrees (one-half electrical cycle) after the fault occurs. In a non current-limiting fuse the fault current continues to flow until extinguished by the cycle of the supply system (zero crossing).

Are all circuit breakers current-limiting?

Some 600A frame breakers can be current limiting, but not as current limiting as the smaller frames. Most breakers rated 800A and higher are not current limiting. Some current limiting breakers were developed to obtain higher interrupting ratings than previously available in older non-current limiting designs.

Are fuses 100 or 80 rated?

RE: Continuous Rating on Fused Disconnect Non-fusible switches are generally rated for 100% continuous duty.