Perhaps you have been confused as to what the markings on circuit breakers suggest? Comprehending the markings on electric equipment is a simple must make sure a secure and dependable electric installation. Circuit breaker marking demands are founded because of the needs based in the NEC additionally the UL 489 product standard. This informative article will talk about the many markings that are common where they may be discovered.
The UL 489 product standard for Molded Case Circuit Breakers specifies the given information to be marked in circuit breakers and where its become situated, so let’s talk about what information has to be marked in the circuit breaker as well as the location in 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 a far 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 normally called 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 called the real face of this 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 made from either a typical journey, where all poles are mechanically tripped caribbeancupid dating apps whenever one of several poles trips, or an unbiased journey construction where just the pole this is certainly involved in 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 foundational dependence on a typical trip function in a circuit breaker; nonetheless, in addition continues 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 doing the NEC for many years. CTL panelboards have actually a rejection means made to reject a lot more than the number that is appropriate of breakers that may be set up when you look at the panel. The marking “For replacement utilize just Not CTL Assemblies” means the circuit breaker does not have CTL rejection provisions and it is meant for replacement in older gear pre-dating the CTL requirements for circuit breakers and panelboards. Circuit breakers with this particular designation must not be set up in a panelboard marked “Class CTL Panelboard” since that might be a breach associated with set of the construction NEC 110.3(B).
Markings Found in Other Areas
The markings we are going to discuss below can happen in almost any location except the straight straight straight back regarding the circuit breaker. These markings consist of:
40°C –This marking suggests the most ambient temperature in that your circuit breaker are used at its marked ampere rating without rerating the ampacity for the circuit breaker. This marking is needed for thermal-magnetic circuit breakers and it is optional for electronic journey circuit breakers unless these are generally just ideal for a 25°C ambient, in which particular case they need to be marked 25°C. Once the temperature that is ambient above 40°C, the designer could need to consult the producer to acquire 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 the true quantity which is why the gear is rated.
HACR type –This marking suggests the circuit breaker would work to be used aided by the team engine installments typically present in heating, ac and refrigeration gear. TheNEC2005 no more has this marking requirement. The electric industry determined that circuit breakers are believed ideal for usage with such gear with no further evaluating, consequently, the HACR marking is not any much much longer required on air cooling and refrigeration equipment or in circuit breakers for usage during these applications. The necessity with this marking has additionally been taken off the UL 1995 product standard for HVAC gear (see product 3 in picture 1).
Optimum cable size –Circuit breakers are generally marked with a cable range, nonetheless 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 should be marked in every location except the rear (see item 5 in picture 3).
Separately 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 straight back (see product 8 in picture 3).