Exactly Just Exactly Exactly What Perform Some Markings on Circuit Breakers Suggest?

Perhaps you have been confused in what the markings on circuit breakers mean? Knowing the markings on electrical equipment is significant must make sure a secure and dependable installation that is electrical. Circuit breaker marking demands are founded by the needs based in the NEC as well as the UL 489 product standard. This informative article will talk about the many typical markings and where they may be discovered.

The UL 489 product standard for Molded Case Circuit Breakers specifies the information to be marked in circuit breakers and where it really is become situated, so let’s talk about what information has to be marked in 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 extra 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 eliminating trims or covers. This location is usually described as the handle escutcheon (see photo 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 on a circuit that is installed with trims or covers eliminated. This location is usually 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 that ought to 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 several poles trips, or a completely independent journey construction where just the pole this is certainly a part of the overcurrent condition trips. Then it should be marked “Independent Trip” or “No Common Trip. If your 2-pole circuit breaker won’t have an inside common journey feature, ” NEC 240.20(B) may be the foundational need for a typical journey function in a circuit breaker; nevertheless, additionally continues to explain where separate journey is allowed.

For Replacement utilize Only not-CTL –The Class CTL (circuit restricting) panelboard has just experienced 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 significantly 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 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 could be a breach of this set of the construction NEC 110.3(B).

Markings Found in Other Places

The markings we’re going to discuss below can happen in every location except the relative back for the circuit breaker. These markings consist of:

40°C –This marking suggests the most temperature that is ambient that your circuit breaker may be used at its marked ampere rating without rerating the ampacity associated with circuit breaker. This marking is necessary for thermal-magnetic circuit breakers and it is optional for electronic journey circuit breakers unless these are generally only suited to a 25°C ambient, in which particular case they need to be marked 25°C. As soon as the temperature that is ambient above 40°C, the designer may prefer to consult producer to have 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 the number which is why the apparatus is ranked.

HACR type –This marking suggests the circuit breaker would work to be used using the combined 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 believed ideal for usage with such gear with no further evaluating, consequently, the HACR marking isn’t any much much much longer required on ac and refrigeration equipment or in circuit breakers for use during these applications. The necessity with this marking has additionally been taken from the UL 1995 product standard for HVAC equipment (see product 3 in picture 1).

Optimum cable size –Circuit breakers are usually marked having a cable range badoo and blendr, nonetheless 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 delivered connectors –If connectors aren’t factory installed for a circuit breaker, then it should be marked using the connectors that are proper terminal kits needed in every location except the straight straight back (see product 8 in picture 3).