Just Just Just What Perform Some Markings on Circuit Breakers Suggest?

Wednesday, January 6, 2021

Just Just Just What Perform Some Markings on Circuit Breakers Suggest?

Perhaps you have been confused in what the markings on circuit breakers suggest? Knowing the markings on electric gear is a simple must make sure a secure and dependable installation that is electrical. Circuit breaker marking demands are founded by the needs based in the NEC therefore the UL 489 product standard. This short article will talk about the many markings that are common where they could be discovered.

The UL 489 product standard for Molded Case Circuit Breakers specifies the information to be marked in circuit breakers and where it really is to be situated, so let’s talk about what information should be marked from the circuit breaker in addition to location for which you will see those markings. Bear in mind the UL® standard specifies requirements that are minimum. Circuit breaker manufacturers may possibly provide more information or offer information in an even more location that is convenient.

Markings Visible without Eliminating Trims or Covers

UL 489 requires that some markings be noticeable without getting rid of trims or covers. This location is usually called the handle escutcheon (see picture 1).

Picture 1. Markings noticeable with trims or covers set up

Markings Visible with Trims or Covers Removed

UL 489 requires other markings be noticeable for a circuit that is installed with trims or covers removed. This location is normally known as the real face associated with circuit breaker (see pictures 2, 3, 4).

Picture 2. Markings noticeable with trims or covers eliminated

Other markings which will be noticeable with trims or covers eliminated are:

Photo 3. Markings visible with trims or covers eliminated

Multi-pole circuit breakers are constructed of either a typical journey, where all poles are mechanically tripped whenever among the poles trips, or an unbiased journey construction where just the pole this is certainly associated with the overcurrent condition trips. Then it must be marked “Independent Trip” or “No Common Trip. In cases where a 2-pole circuit breaker doesn’t have an inside common journey feature, ” NEC 240.20(B) could be the requirement that is foundational a typical journey function in a circuit breaker; nevertheless, in addition continues on to explain where separate journey is allowed.

For Replacement utilize only–The that is not-CTL class (circuit restricting) panelboard has just held it’s place in existence for approximately 25 years, although the illumination and appliance branch circuit panelboard has been around the NEC for a long time. CTL panelboards have actually a rejection means made to reject a lot more than the number that is appropriate of breakers which can be set up in the panel. The marking “For replacement utilize just Not CTL Assemblies” means the circuit breaker won’t have CTL rejection provisions and is designed for replacement in older gear pre-dating the CTL requirements for circuit breakers and panelboards. Circuit breakers with this particular designation ought not to be set up in a panelboard marked “Class CTL Panelboard” since that could be a breach associated with the report on the installation NEC 110.3(B).

Markings Found in Other Places

The markings we are going to discuss below can happen in every location except the relative straight straight straight back of this circuit breaker. These markings consist of:

40°C –This marking suggests the most temperature that is ambient that the circuit breaker is used at its marked ampere rating without rerating the ampacity regarding the circuit breaker. This marking is needed for thermal-magnetic circuit breakers and it is optional for electronic journey circuit breakers unless they’re just ideal for a 25°C ambient, in which particular case they have to be marked 25°C. Once the ambient heat rises above 40°C, the designer could need to consult the company to acquire rerating information (see product 4 in photo 3).

Class CTL –Circuit breakers marked Class CTL have actually a rejection means created in to the circuit breaker. Class CTL panelboards or assemblies, along with Class CTL circuit breakers, avoid more circuit breaker poles from being set up compared to the quantity which is why the gear is ranked.

HACR type –This marking suggests the circuit breaker would work to be used aided by the combined team engine installments typically present in heating, air-con and refrigeration gear. TheNEC2005 no more has this marking requirement. The electric industry determined that circuit breakers are thought ideal for usage with such gear with no further screening, consequently, the HACR marking isn’t any much longer required on air cooling and refrigeration equipment or in circuit breakers to be used during these applications. The necessity because of this marking has additionally been taken off the UL caffmos 1995 product standard for HVAC gear (see product 3 in photo 1).

Optimum cable size –Circuit breakers are usually marked having a cable range, nonetheless that marking isn’t mandatory. In the event that circuit breaker cannot accept the second bigger cable size needed for the ampere score, then the utmost wire size must certanly be marked in almost any location except the rear (see product 5 in picture 3).

Individually delivered connectors –If connectors aren’t factory installed for a circuit breaker, then it should be marked because of the appropriate connectors or terminal kits needed in every location except the straight straight back (see product 8 in picture 3).