Siemens HLD63B450 Molded Case Circuit Breaker

This LD-frame breaker is designed for use in Siemens Sentron Type P4 and P5 panelboards, as well as SB1, SB2, and SB3 switchboards. It can also be installed in standalone Siemens enclosures.

The factory-installed lugs accept two conductors per phase. For copper wire, the supported range is 3/0 AWG to 500 kcmil. For aluminum wire, the range is 4/0 AWG to 500 kcmil.

The HLD63B450 features a fixed thermal element for overload protection and an adjustable magnetic element for short-circuit protection. The instantaneous magnetic trip threshold can be dialed in by the installer to coordinate with downstream devices and specific load inrush characteristics.

The primary difference is the interrupting capacity. The LD63B450 is a standard-interrupting breaker rated at 35kAIC at 480V. The HLD63B450 is the high-interrupting version, rated at 65kAIC at 480V. Both share the same physical dimensions and mount in the same LD-frame spaces.

The LI designation indicates the breaker provides Long-Time and Instantaneous protection. Long-Time protects the circuit against sustained overloads by using a thermal element. Instantaneous protects against sudden short-circuits using a magnetic element that trips the breaker immediately when a high fault current is detected.

No, the HLD63B450 is a standard 80 percent rated breaker. For continuous loads requiring a 100 percent rating, Siemens typically requires an HLXD frame with an H suffix, along with specific 90-degree Celsius copper cabling and specialized lugs.

It is a unit-mount, bolt-on circuit breaker. This means it bolts directly to the busbars or mounting pans in compatible Sentron panels and switchboards, providing a secure mechanical and electrical connection for high-amperage applications.