Exactly Exactly What Perform Some Markings on Circuit Breakers Suggest?

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Exactly Exactly What Perform Some Markings on Circuit Breakers Suggest?

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

The UL 489 product standard for Molded Case Circuit Breakers specifies the given information to be marked in circuit breakers and where it really is to be situated, so let’s talk about what information has to be marked regarding the circuit breaker and also the location where you will see those markings. Bear in mind the UL® standard specifies requirements that are minimum. Circuit breaker manufacturers might provide more information or offer information in a far more location that is convenient.

Markings Visible without Eliminating Trims or Covers

UL 489 requires that some markings be visible without eliminating trims or covers. This location is normally named the handle escutcheon (see picture 1).

Picture 1. Markings noticeable with trims or covers in position

Markings Visible with Trims or Covers Removed

UL 489 requires other markings be noticeable for an installed circuit breaker with trims or covers eliminated. This location is normally described as the face associated with the 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 free Atheist adult dating eliminated are:

Photo 3. Markings visible with trims or covers removed

Multi-pole circuit breakers are made from either a typical journey, where all poles are mechanically tripped whenever one of many poles trips, or a completely independent journey construction where just the pole that is associated with the overcurrent condition trips. Then it should be marked “Independent Trip” or “No Common Trip. In case a 2-pole circuit breaker won’t have an inside common journey feature, ” NEC 240.20(B) may be the requirement that is foundational a typical journey function in a circuit breaker; nevertheless, in addition continues to explain where separate journey is allowed.

For Replacement utilize Only not-CTL –The Class CTL (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 significantly more than the number that is appropriate of breakers that may be set up within the panel. The marking “For replacement utilize just Not CTL Assemblies” means that the circuit breaker doesn’t have rejection that is CTL and it 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 for the set of the installation NEC 110.3(B).

Markings Found in Other Places

The markings we’re going to discuss below can happen in almost any location except the straight straight back regarding the circuit breaker. These markings consist of:

40°C –This marking shows the most ambient temperature in that the circuit breaker are used at its marked ampere rating without rerating the ampacity associated with the circuit breaker. This marking is needed for thermal-magnetic circuit breakers and it is optional for electronic journey circuit breakers they must be marked 25°C unless they are only suitable for a 25°C ambient, in which case. If the ambient heat rises above 40°C, the designer might need to consult the producer to have rerating information (see product 4 in photo 3).

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

HACR type –This marking suggests the circuit breaker works for usage because of the combined team engine installments typically present in heating, ac and refrigeration gear. TheNEC2005 no further has this marking requirement. The electric industry determined that circuit breakers are thought appropriate usage with such gear with no further evaluation, consequently, the HACR marking is not any much much much longer required on air cooling and refrigeration equipment or in circuit breakers to be used in these applications. The requirement with this marking has additionally been taken from the UL 1995 product standard for HVAC gear (see product 3 in picture 1).

Maximum cable size –Circuit breakers are generally marked with a cable range, nevertheless that marking isn’t mandatory. In the event that circuit breaker cannot accept the following bigger cable size necessary 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 on a circuit breaker, then it should be marked with all the connectors that are proper terminal kits needed in virtually any location except the straight back (see product 8 in picture 3).



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