Just Just Exactly What Do the Markings on Circuit Breakers Suggest?
Product Information
Maybe you have been confused by what the markings on circuit breakers mean? Comprehending the markings on electric gear is a simple must make sure a safe and dependable electric installation. Circuit breaker marking demands are founded by the requirements based in the NEC plus 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 its become situated, so let’s talk about what information has to be marked regarding the circuit breaker as well as the location for which you will see those markings. Remember the UL® standard specifies requirements that are minimum. Circuit breaker manufacturers might provide more information or offer information in a far more convenient location.
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 described as 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 a circuit that is installed with trims or covers eliminated. 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 visible with trims or covers eliminated are:
Photo 3. Markings visible with trims or covers eliminated
Multi-pole circuit breakers are constructed of either a trip that is common where all poles are mechanically tripped whenever one of many poles trips, or a completely independent journey construction where just the pole that is involved in the overcurrent condition trips. Then it must be marked “Independent Trip” or “No Common Trip. If your 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; nonetheless, additionally 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 around 25 years, although the illumination and appliance branch circuit panelboard has been around the NEC for many years. CTL panelboards have actually a rejection means made to reject a lot more than the appropriate wide range of circuit 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 CTL rejection provisions and it is designed for replacement in older gear pre-dating the CTL requirements for circuit breakers and panelboards. Circuit breakers with this specific designation must not be set up in a panelboard marked “Class CTL Panelboard” since that could be a violation of this set of the construction NEC 110.3(B).
Markings Found in Other Areas
The markings we shall discuss below can happen in almost any location except the straight straight back of this circuit breaker. These markings consist of:
40°C –This marking suggests the most ambient temperature in that the circuit breaker may be used at its marked ampere rating without rerating the ampacity associated with the circuit breaker. This marking is necessary 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. 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 true quantity which is why the gear is ranked.
HACR type –This marking suggests the circuit breaker would work to be used utilizing the combined https://datingmentor.org/bdsm-com-review/ team engine installments typically present in heating, air cooling 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 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 1995 product standard for HVAC equipment (see product 3 in picture 1).
Optimum cable size –Circuit breakers are generally marked with a cable range, nevertheless that marking is certainly not 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 delivered connectors –If connectors aren’t factory installed on a circuit breaker, then it should be marked using the connectors that are proper terminal kits needed in every location except the straight straight straight back (see product 8 in picture 3).
