Seismic Certification of Model 6 MCCs

Model 6 Motor Control Centers that are seismically certified have been certified to the seismic requirements of the listed regional building codes and/or seismic design standards per the manufacturer’s certificate of compliance (CoC). Equipment labels and CoCs are provided with all seismically certified Model 6 Motor Control Centers. Refer to the equipment CoC for certification details and applicable seismic parameters. To maintain the validity of this certification, the installation instructions provided in this section must be followed.

Model 6 MCCs are considered nonstructural building components, as defined by regional building codes and seismic design standards. Equipment capacity was determined from tri-axial seismic shake table test results in accordance with the International Code Counsel Evaluation Service (ICC ES) Acceptance Criteria for Seismic Certification by Shake-TableTesting of Nonstructural Components (AC156).

An equipment importance factor, I_p, that is greater than one (I_p > 1.0) is assumed and indicates that equipment functionality is required after a seismic event and after seismic simulation testing. This importance factor is applicable for designated seismic systems, for example, special certification, servicing critical infrastructure where post- earthquake equipment functionality is a requirement.

Incoming and outgoing bus, cable, and conduit must also be considered as related, but independent, systems. These distribution systems must be designed and restrained to withstand the forces generated by the seismic event without increasing the load transferred to the equipment. For applications where seismic hazard exists, it is preferable for bus, cable, and conduit to enter and exit the bottom of the equipment enclosure.

Seismic qualification of nonstructural components and equipment by Schneider Electric is just one link in the total chain of responsibility required to maximize the probability that the equipment is intact and functional after a seismic event. During a seismic event, the equipment must be able to transfer the inertial loads that are created and reacted through the equipment’s force resisting system and anchorage to the load-bearing path of the building structural system or foundation.

Anchorage of equipment, for example, nonstructural supports and attachments, to the primary building structure or foundation is required to validate seismic conformance. The construction site structural engineer or registered design professional or engineer of record (EOR) is responsible for detailing the equipment anchorage requirements for the given installation. The installer and manufacturers of the anchorage system are responsible for assuring the mounting requirements are met. Schneider Electric is not responsible for the specification and performance of anchorage systems.

The equipment enclosure provides anchorage tie-down points to accept anchor attachments to the building structure or foundation. Model 6 MCC indoor enclosures provide enclosure base frame clearance holes for bolted anchorage attachments, as shown in Type 1, Type 1 Gasketed, Type 1 Sprinkler Resistant, and Type 12 Seismic Tie Down Locations and Seismic Tie-Down Locations for 18-Pulse AC Drive MCC Sections. Model 6 MCC outdoor enclosures provide enclosure base frame clearance holes for bolted anchorage attachments, as shown in Type 3R Seismic Tie-Down Locations.

MCC sections must be anchored using all enclosure tie-down points, as shown in the previous referenced topics, for indoor and outdoor applications.

The bolted anchor assembly view depicted in Bolted Anchor Assembly illustrates the equipment’s as-tested attachment to a seismic shake-table test fixture. The equipment seismic capacity, as stated on the Schneider Electric CoC, was achieved with the identified size and grade attachment hardware. For bolted attachments, the use of factory-supplied Belleville conical spring washers at specified locations is required to maintain seismic conformance. Field installed equipment attachment and support detailing must be in accordance with the anchorage system requirements as defined by the construction site structural engineer, registered design professional, or engineer of record.

Bolted Anchor Assembly

Equipment installations using welded supports and attachments in lieu of bolted supports and attachments must ensure the weld locations are distributed similarly to the locations of enclosure anchorage clearance holes. Welded supports and attachments must be properly sized to ensure the weldment withstand capacity exceeds the earthquake demand at the equipment installation location. Precautions must be taken to properly vent and shield the equipment enclosure during the field welding process. Paint must be removed from the equipment weld locations before welding, and then replaced after welding is complete to inhibit corrosion.

Each section must be anchored per detail supplied by engineer of record to the load bearing path of the building structural system. For floor mounting locations, see Type 1, Type 1 Gasketed, Type 1 Sprinkler Resistant, and Type 12 Seismic Tie Down Locations or Seismic Tie-Down Locations for 18-Pulse AC Drive MCC Sections. Use 0.50 in. or 0.75 in. grade 5 or higher bolts and Belleville washers. Torque bolts to the value specified by the manufacturer of the anchor.

When specified or required for the application (all seismic hazard areas with S_s in excess of 2.67g), each section must be laterally braced at the top (bracing supplied by others) and connected to the load-bearing path of the building system per detail supplied by engineer of record. Refer to the current International Building Code or NFPA 5000 for location specific values of S_s.

DANGER
Hazard of electric shock, explosion, or arc flash Turn off power supplying equipment before installing lateral bracing. Bolts must not penetrate top plate by more than 0.50 in. (12.7 mm). Failure to follow these instructions will result in death or serious injury.

Remove the lifting angle and fasten each section to the lateral restraint system using the same attachment points used to secure the lifting angle. Re-use bolts [3/8 (.375 in.) by 7/8 (.875 in.) long #16 thread] and lock washer (.094 in. thick) supplied with the lifting angle or hardware supplied by others as appropriate. Pay particular attention to the limitation on the depth the bolt can penetrate below the surface of the top plate. The bolts must not penetrate the top plate of the enclosure by more than 0.50 in. (12.7 mm).

NOTE: On arc-rated MCCs, do not block roof flaps with lateral restraint components.

Attachment Locations for Top Lateral Bracing NOTE: The dimensions shown are for locating top lateral bracing locations within individual MCC sections. Refer to factory supplied drawings to determine appropriate anchor locations for the top lateral brace support system.
15 (381) Section Dimensions Letter Section Width Dimension A N/A 5.25 (133) B N/A 15.00 (381) C 20.00 (508) 18.40 (467) 25.00 (635) 23.40 (594) 30.00 (762) 28.40 (721) 35.00 (889) 33.40 (848) D N/A 0.80 (20) N/A = Not applicable	20 (508) Section Dimensions Letter Section Width Dimension A (single lifting angle) N/A 10.25 (260) A (two lifting angles) N/A 1.91 (48) B N/A 20.00 (508) C 20.00 (508) 18.40 (467) 25.00 (635) 23.40 (594) 30.00 (762) 28.40 (721) 35.00 (889) 33.40 (848) D N/A 0.80 (20) N/A = Not applicable