Perhaps you have been confused in what the markings on circuit breakers suggest? Comprehending 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 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 it really is become situated, so let’s talk about what information should be marked regarding the circuit breaker as well as the location for which you will see those markings. Bear in mind the UL® standard specifies minimal demands. Circuit breaker manufacturers might provide more information or offer information in an even more convenient location.
Markings Visible without Eliminating Trims or Covers
UL 489 requires that some markings be noticeable without eliminating 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 an installed circuit breaker with trims or covers eliminated. This location is usually known as the real face associated with the circuit breaker (see pictures 2, 3, 4).
Picture 2. Markings noticeable with trims or covers eliminated
Other markings that ought to 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 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 a part of the overcurrent condition trips. Then it should be marked “Independent Trip” or “No Common Trip. In cases where a 2-pole circuit breaker doesn’t have an interior common journey feature, ” NEC 240.20(B) may be the foundational dependence on 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 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 when you look at 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 designed 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 could be a violation associated with 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 every location except the straight straight straight straight back associated with circuit breaker. These markings include:
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 regarding the circuit breaker. This marking is necessary for thermal-magnetic circuit breakers and it is optional for electronic journey circuit breakers unless these are generally just suited to 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 designed to the circuit breaker. Class CTL panelboards or assemblies, along with Class CTL circuit breakers, avoid more circuit breaker poles from being installed compared to the true quantity which is why the gear is ranked.
HACR type –This marking suggests the circuit breaker works to be used using the team engine installments typically present in heating, air cooling and refrigeration gear. TheNEC2005 no further has this marking requirement. The electric industry determined that circuit breakers are thought appropriate usage with such gear without the further evaluation, consequently, the HACR marking isn’t any much longer required on air-con and refrigeration equipment or on circuit breakers to be used within these applications. The necessity because of this marking has additionally been taken from 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, nevertheless that marking is certainly not mandatory. In the event that circuit breaker cannot accept the second bigger cable size needed for the ampere score, then the utmost wire size should 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 https://datingmentor.org/xdating-review/ circuit breaker, then it should be marked with all the appropriate connectors or terminal kits needed in just about any location except the straight straight straight straight back (see product 8 in photo 3).