Perhaps 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 secure and dependable electric installation. 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 typical markings and 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’s become situated, so let’s talk about what information has to be marked from the circuit breaker therefore the location for which you will discover those markings. Consider the UL® standard specifies minimal needs. Circuit breaker manufacturers might 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 known as the handle escutcheon (see photo 1).
Picture 1. Markings visible with trims or covers set up
Markings bikerplanet reviews Visible with Trims or Covers Removed
UL 489 requires other markings be noticeable for a circuit that is installed with trims or covers eliminated. This location is normally named the real face for 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 eliminated are:
Photo 3. Markings visible with trims or covers eliminated
Multi-pole circuit breakers are constructed of either a common journey, where all poles are mechanically tripped whenever one of many poles trips, or an unbiased journey construction where just the pole that is a part of the overcurrent condition trips. If your 2-pole circuit breaker won’t have an interior typical journey function, then it should be marked “Independent Trip” or “No Common Trip. ” NEC 240.20(B) may be the requirement that is foundational a typical journey function in a circuit breaker; but, in addition continues on 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, even though the illumination and appliance branch circuit panelboard has been doing the NEC for many years. CTL panelboards have actually a rejection means made to reject significantly more than the number that is appropriate of breakers which can be set up into the panel. The marking “For replacement utilize just Not CTL Assemblies” means the circuit breaker won’t have rejection that is CTL and it is meant for replacement in older gear pre-dating the CTL requirements for circuit breakers and panelboards. Circuit breakers with this specific designation ought not to be set up in a panelboard marked “Class CTL Panelboard” since that could be a breach regarding the set of the installation NEC 110.3(B).
Markings Found in Other Places
The markings we are going to discuss below can happen in just about any location except the straight straight back of this circuit breaker. These markings consist of:
40°C –This marking shows the most ambient temperature in that the circuit breaker could be used at its marked ampere rating without rerating the ampacity of this circuit breaker. This marking is necessary for thermal-magnetic circuit breakers and it is optional for electronic trip circuit breakers they must be marked 25°C unless they are only suitable for a 25°C ambient, in which case. Once the ambient heat rises above 40°C, the designer may prefer to consult the company to get 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, together with Class CTL circuit breakers, avoid more circuit breaker poles from being set up compared to true quantity which is why the apparatus is ranked.
HACR type –This marking suggests the circuit breaker would work for usage utilizing the 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 equipment with no further screening, consequently, the HACR marking isn’t any much much much longer required on air-con and refrigeration equipment or in circuit breakers to be used during these applications. The necessity because of this marking has additionally been taken from the UL 1995 product standard for HVAC gear (see item 3 in picture 1).
Optimum cable size –Circuit breakers are usually marked with a cable range, nevertheless that marking just isn’t mandatory. Then the maximum wire size must be marked in any location except the back (see item 5 in photo 3) if the circuit breaker cannot accept the next larger wire size required for the ampere rating,.
Individually shipped connectors –If connectors aren’t factory installed on a circuit breaker, then it should be marked with all the appropriate connectors or terminal kits needed in every location except the back (see product 8 in picture 3).