tiastar™ arc-resistant motor control centers

Arc-resistant motor control center

Up to 

600 V
  • Maximum horizontal bus rating 1,600 A

  • Maximum vertical bus rating 800 A

  • Multiple size options and enclosure types available

tiastar arc-resistant MCCs

Siemens type 2A arc-resistant, low-voltage motor control centers are tested in accordance to IEEE C37.20.7, which contains and channels internal arcing fault incident energy. They provide an additional degree of protection to the personnel performing normal operating duties in close proximity to the equipment while the equipment is operating under normal conditions. Type 2A accessibility means the MCCs protect the operator in front, back, and sides of the equipment.


Siemens tiastar arc-resistant MCCs showcase state-of-art overarching technology. This means one can get an arc-resistant MCC that can have various smart components with communications, and/or high-density compact units. Other options include SIERS integrated electrical-racking system via retractable stabs and Sm@rtGear power distribution solution.

  • Automatic shutters
  • Reinforced doors
  • Insulated bus bar
  • Bolted wireway
  • Internal venting system
  • Deflectors
  • Modified pull-box with pressure flap.


Watch the videos below to learn more about the Siemens tiastar low-voltage motor control center family and the SIERS retractable stabs option.


  • Automatic shutters - The barrier automatically opens and closes to allow insertion or removal of units. It isolates the vertical bus to prevent inadvertent contact lowering the risk to personnel.
  • Insulated bus bar - Isolates energized components, prevents accidental contact, and keeps arcing faults from propagating.
  • Reinforced doors - Reinforced cabinet doors ensure the equipment can withstand and contain pressure from internal arcing faults.
  • Bolted wireway - The wireway is bolted to ensure integrity of the MCC wireway is sustained during an arc-flash incident.
  • Interal venting system - The vertical wireway is perforated with holes that channel the gasses to the back and out the top of the MCC.
  • Deflectors - The protection plate allows MCCs to have vented doors and will redirect arc-flash by-products.
  • Modified pull-box with pressure flap - The arc-flash by-products will be prevented from escaping due to the wire mesh, while the pressure flap will allow pressure release.


  • UL-witnessed - The first of its class that adheres to IEEE C37.20.7 standards with UL witnessed testing.

  • Dynamic Arc-flash Sentry (DAS) - Now available in tiastar MCCs, this technology from our Siemens WL main circuit breakers can reduce the arc-flash hazard category for the motor control center.

  • 6” high-density units are available in arc-resistant MCCs. 

  • Arc-resistant technology - Siemens has incorporated advanced technology and strengthened structural design to improve the safety potential of MCCs. 

  • Main-lug only (MLO) permitted for arc-resistant MCCs - With our innovative arc-resistant MCC design, there is no requirement of having a main circuit breaker or a current-limiting device inside the MCC. Consult your Siemens representative for ratings.

1 The arc-resistant MCC should not be spliced to a non-arc-resistant MCC.
Bus and electrical ratings
Maximum horizontal bus
1,600 A
Maximum vertical bus
800 A
Maximum short-circuit withstand
65 kA
Arc-flash duration
50 ms (3 cycles) 
Maximum voltage
600 V
Horizontal bus details
Copper only
MLO, MCB/MDS 1,600 A max, splice to existing1
Enclosure type 
NEMA 1 and 1A
High-density units option
VFD, RVSS units
Double-deep option
1 If the mounting channels are surface mounted then the minimum height is 103” (90” MCC height + 1” mounting channels + 12” modified pull box). Also, note that the total MCC height will increase if standard modified pull box is not selected.
Modified pull-box height 
12” minimum (standard), 18”, and 24” (optional)
Section depth
Section width
20” or 30”
Total MCC height
102” minimum1
Room requirements
112” minimum ceiling height (total MCC height + 10”); 38” minimum aisle

To complement the arc-resistant MCC, the Dynamic Arc-flash Sentry (DAS) option is available. DAS is a patented feature available in both Siemens MCCs and type WL low-voltage switchgear. The unique dual-trip setting technology reduces the energy available in an arc-flash event.

Mailing address

Siemens Industry, Inc.

7000 Siemens Road

Wendell, North Carolina 27591

United States of America