Siemens CMD63B800 Molded Case Circuit Breaker
- 800A
- 3 Pole
- Unit Mount
Quantity
Siemens CMD63B800 - 800A 3 Pole Molded Case Circuit Breaker
New
Quantity
Description
Engineered for demanding commercial and industrial environments, the CMD63B800 is a 3-pole, 800A molded case circuit breaker from the Siemens Sentron family. This MD Frame unit delivers robust current-limiting performance with a high interrupting capacity of 100kA at 480VAC. It installs into Siemens P4 and P5 panelboards, switchboards, and enclosures. Featuring a non-interchangeable thermal-magnetic trip unit, it provides fixed long-time and adjustable instantaneous (LI) protection.Specifications
| Brand | Siemens |
|---|---|
| Series | CMD6 |
| Amperage | 800A |
| Poles | 3 |
| Mounting Style | Unit Mount |
| Voltage | 240VAC, 480VAC, 600VAC, 250VDC, 500VDC |
| Phase | 3 |
| AIC Rating | 200kA @ 240VAC, 100kA @ 480VAC, 65kA @ 600VAC, 50kA @ 250VDC, 25kA @ 500VDC |
| Terminal Type | Lugs |
|---|---|
| For Use With | Siemens Sentron P4, P5 Panelboards, Switchboards, Enclosures |
| Wire Gauge | (3) 1/0 AWG - 500 kcmil (Cu/Al) |
| Max Wire | 500 kcmil |
| Min Wire | 1/0 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed Thermal, Adjustable Magnetic |
| Available Options | Shunt Trip, Auxiliary Switch, Alarm Switch, Undervoltage Release, Lug Kits |
|---|---|
| Accessories | Lugs Not Included |
| Standards | CSA C22.2 No. 5, IEC 60947-2, NEMA AB 1, UL 489 |
| Approval | CSA, HACR, IEC, UL |
| Temp Rating | 40C |
| Construction Features | Current Limiting, High Interrupting Capacity, HACR Rated, Non-Interchangeable Trip |
Product FAQs
8 answersWhat panelboards and switchboards accept the CMD63B800?
This Sentron MD-frame breaker installs directly into Siemens Sentron P4 and P5 panelboards, as well as Siemens switchboards and standalone enclosures designed for unit-mount hardware.
Which lug kit is used with the CMD63B800, and what wire does it accept?
The standard factory lug component for this 800A breaker is the TA3K500 aluminum-body lug kit. It features a 3-barrel design that accepts up to three 1/0 AWG to 500 kcmil copper or aluminum conductors per phase for both line and load side connections.
How does the CMD frame differ from standard Siemens MD or HMD frames?
The "C" in the CMD prefix indicates the highest interrupting capacity available in the Sentron MD-frame line. It operates as a fuseless current-limiting breaker rated up to 100kA at 480VAC, whereas standard MD or HMD frames have lower maximum short-circuit tolerances.
Can the CMD63B800 be deployed in DC distribution systems?
Yes, in addition to its AC ratings, this breaker is rated for DC systems. It offers an interrupting capacity of 50kA at 250VDC and 25kA at 500VDC, making it suitable for high-capacity direct current applications.
How is the thermal-magnetic trip unit adjusted on this breaker?
The CMD63B800 has a fixed thermal element for long-time overload protection. However, the instantaneous magnetic trip is adjustable via front-facing dials, allowing electricians to customize the short-circuit pickup to accommodate specific motor inrush or fault current requirements.
Are the trip units on the CMD63B800 interchangeable?
No. The "B" in the CMD63B800 catalog number indicates that it comes factory-assembled with a non-interchangeable thermal-magnetic trip unit. Facilities requiring field-interchangeable trip functions must source a different frame variant.
Can the CMD63B800 replace older ITE 800A circuit breakers?
Yes. Because Siemens acquired ITE, modern Sentron MD-frame breakers share the same physical footprint (16 inches by 9 inches by 6 inches) as legacy ITE MD-frame breakers. It can serve as a direct unit-mount replacement, provided the fault current requirements are met.
What is the ambient temperature calibration for the CMD63B800?
The thermal-magnetic trip elements are factory calibrated for a standard 40 degrees Celsius (104 degrees Fahrenheit) operating environment. Operating in ambient temperatures significantly above this threshold may require load derating calculations to prevent nuisance tripping.
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