Exactly Just What Perform Some Markings on Circuit Breakers Mean?

Exactly Just What Perform Some Markings on Circuit Breakers Mean?

Have you ever been confused as to what the markings on circuit breakers suggest? Comprehending the markings on electric gear is a simple must make sure a secure and dependable installation that is electrical. Circuit breaker marking demands are established by the needs based in the NEC and also the UL 489 product standard. This short 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 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 regarding the circuit breaker as well as the location in which you will discover 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 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 normally described as the handle escutcheon (see picture 1).

Picture 1. Markings noticeable with trims or covers set up

Markings Visible with Trims or Covers Removed

UL 489 requires other markings be noticeable for an installed circuit breaker with trims or covers removed. This location is usually called the real face associated with circuit breaker (see pictures 2, 3, 4).

Picture 2. Markings noticeable with trims or covers eliminated

Other markings that should 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 typical journey, where all poles are mechanically tripped whenever one of many poles trips, or a completely independent trip construction where just the pole this is certainly a part of 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) may be the foundational dependence on a typical journey function in a circuit breaker; nonetheless, additionally 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 around 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 number that is appropriate of breakers that may be set up into the panel. The marking “For replacement utilize just Not CTL Assemblies” means the circuit breaker doesn’t have CTL rejection provisions and it is intended for replacement in older gear pre-dating the CTL requirements for circuit breakers and panelboards. Circuit breakers with this particular designation should not be set up in a panelboard marked “Class CTL Panelboard” since that could be a breach associated with set of the installation NEC 110.3(B).

Markings Found in Other Places

The markings we’re going to discuss below can happen in just about any location except the straight back of this circuit breaker BBW dating websites free. 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 associated with 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. If the ambient heat rises above 40°C, the designer may prefer to consult the company to acquire 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 quantity which is why the gear is ranked.

HACR type –This marking suggests the circuit breaker would work to be used with all the combined team engine installments typically present in heating, ac and refrigeration equipment. TheNEC2005 no more has this marking requirement. The electric industry determined that circuit breakers are believed ideal for usage with such gear without the further evaluating, consequently, the HACR marking is not any much much longer required on ac and refrigeration equipment or in circuit breakers for usage in these applications. The requirement because of 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 usually marked by having a cable range, nonetheless 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,.

Separately delivered connectors –If connectors aren’t factory installed for a circuit breaker, then it should be marked utilizing the connectors that are proper terminal kits needed in every location except the back (see product 8 in picture 3).

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