ASCO 300 Series Transfer Switches (E3ATS/E3NTS) 260 & 400 Amperes Outline

Diagram Description

This document provides outline drawings and dimensional data for ASCO 300 Series E3ATS/E3NTS automatic transfer switches, rated for 260 and 400 amperes, in an open type configuration.

Page 1 presents a schematic of the transfer switch, illustrating 3-pole or 2-pole configurations with options for an overlapping neutral pole. It details terminal connections for Phase A, Phase B, Phase C, and Neutral (LN, NN), along with various dimensions and mounting hole locations. The drawing also indicates standard and maximum overhangs for components.

Page 2 focuses on control panel and power meter mounting data. It includes front and side views of the control panel mounting arrangement, specifying required clearances, such as a minimum of 6.00 inches [152.4mm] for door control. Detailed cutout and mounting hole dimensions are provided for different enclosure types (Type 1, Type 3R, 4, & 12) through specific details (A-1, B-1, A-2, B-2).

General Notes

The standard switch configuration features top-mounted Load and Emergency sources and bottom-mounted Normal source.
Neutral configurations include optional full-rated neutrals: solid (copper bus), switched neutral pole (available only on 2-pole units), or overlapping neutral pole.
Standard terminal lugs are mechanical (screw type) AL/CU.
Conductors should be connected to similarly marked phases of the Normal, Emergency, and Load connections.
All internal connections are factory-made.
Maintain an electrical clearance of 1.00 inch [25.4mm] between live metal parts and grounded metal.
For enclosure mounting, a minimum depth of 6.00 inches [152.4mm] is required for controls on the inside rear surface of the door.
Control panels connect to the transfer switch via a harness with quick disconnect plug(s), exiting on the right side. Extension harnesses are available from the factory.
Specific cutout data for Type 1 enclosures is found in Detail A-1 and Detail B-1. For Type 3R, 4, & 12 enclosures, refer to Detail A-2 & Detail B-2. Gaskets and bezels are supplied for Type 3R, 4, & 12 enclosures.

Cable Accommodations & Cabling Notes

Cable Accommodations (per phase & neutral)

Screw Type (Standard): Accommodates (2) 1/0 - 250 MCM AL/CU cables or (1) #4 - 600 MCM AL/CU cable.

Cabling Notes

Standard lugs are mechanical (screw type).
Lug material: Aluminum Alloy 6061-T6 with electro tin plated finish.
Screw material: Aluminum Alloy 6262-19 with electro tin plated finish.
Products are UL Listed and CSA Certified.
Screw tightening torque for lugs is 19 FT-LBS per UL 486B.

Switch Notes (260-400 AMP Switches)

Supplied with standard mechanical (screw type) lugs on the Normal, Emergency, and Load bus stabs. Each stab is suitable for connecting two (2) 1/0 - 250 MCM CU/AL cables or one (1) #4 - 600 MCM CU/AL cable.

Enclosure and Mounting Dimensions

Minimum Required Enclosure Size

Switch Rating (AMPS)	Height (INCH / MM)	Width (INCH / MM)	Depth (INCH / MM)
260-400 AMPS	48.00 (1219.2)	18.00 (457.2)	13.00 (330.2)

Suggested Bolt Size for Mounting ATS

1/4-20 x 3.00" LONG MINIMUM QUANTITY (4)

Overall Dimensions (2 and 3 Pole with and without Overlapping Neutral)

Dimension	Value (INCH)	Value (MM)
A	11.00	279.4
B	12.00	304.8
C	6.87	174.5
D	10.00	254.0
E	0.50	12.7
F	11.00	279.4
G	0.50	12.7
H	3.87	98.3
J	2.12	53.8
K	2.12	53.8
L	0.31	7.9
T	4.93	125.2
U	3.00	76.2
W	2.12	53.8

Control Panel & Power Meter Data

Control Panel & Controls Mounting

The document illustrates the mounting of control panels and associated controls. A minimum door control clearance of 6.00 inches [152.4mm] is required. The arrangement includes space for the control panel, an optional power meter, and a user interface cutout. Mounting rails are provided for operator controls or DIN rail mounted accessories.

Cutout and Mounting Details

Specific details are provided for different enclosure types:

Detail A-1 (For Type 1): Provides dimensions for control panel and user interface mounting cutouts.
Detail B-1 (For Type 1): Provides dimensions for mounting operator controls or DIN rail mounted accessories.
Detail A-2 (For Type 3R, 12 & 4): Provides dimensions for control panel and user interface mounting cutouts for these enclosure types.
Detail B-2 (For Type 3R, 12 & 4): Provides dimensions for mounting operator controls or DIN rail mounted accessories for these enclosure types.

Add-on panels can be mounted using specified PEM studs (e.g., Ø0.25" DIA. & 1/4-20 x 1.50" LONG PEM STUD).

Manufacturer Information

ASCO Power Technologies, L.P.
Florham Park, New Jersey 07932 U.S.A.

Drawing Number: 978732-002

Revision: B, ECN 265705

	ASCO 300 Series Transfer Switches Outline Drawing - 30-200 Amperes, Type 1 Enclosure Detailed outline drawing for ASCO 300 Series Transfer Switches (D3ATS/D3NTS) rated 30-200 Amperes, Type 1 enclosure, including physical dimensions, general notes, and technical specifications.
	ASCO 300 Series Transfer Switches (E3ATS/E3NTS) 200-400A Type 1 Enclosure Outline Technical outline drawing and specifications for ASCO 300 Series (E3ATS/E3NTS) 200-400 Ampere, Type 1 Enclosure transfer switches. Includes dimensions, general notes, cabling details, and unit weights.
	ASCO Series 300 Manual Transfer Switch (MTS) Operator's Manual - J-design, 150-600 Amperes Operator's manual for ASCO Series 300 Manual Transfer Switches (MTS), J-design models rated 150 through 600 Amperes. Covers installation, manual operation, testing, and maintenance procedures for safe and effective use.
	ASCO Series 300 Automatic Transfer Switch Wiring Diagrams and Technical Data Comprehensive technical document detailing wiring diagrams, control schematics, physical layout, and operator controls for ASCO Series 300 Automatic Transfer Switches (ATS) with Group 1 Controls, available in 600, 800, 1000, and 1200 Ampere ratings. Includes wire run lists and accessory information.
	ASCO 300 Series G3MGDQ Transfer Switch Wiring Diagrams and Specifications Detailed wiring diagrams, connection schematics, and accessory specifications for ASCO 300 Series manually operated transfer switches (Type G3MGDQ), rated for 1000-3000 Amperes. Includes information on field connections, power poles, optional accessories, and wire run listings.
	ASCO Series E386 Non-Automatic Transfer Switches Wiring Diagrams and Specifications Detailed wiring diagrams, connection information, and specifications for ASCO Series E386 Non-Automatic Transfer Switches rated 260 & 400 Amperes with Group I Controls. Includes information on features, optional accessories, and physical layout.
	ASCO 300 Series D2ATS/D2NTS Automatic Transfer Switch Outline and Mounting Technical outline and mounting specifications for ASCO 300 Series D2ATS/D2NTS Automatic Transfer Switching Equipment, rated 30-200 Amperes, Type 1 enclosure. Includes dimensions, general notes, power connection details, and project information.
	ASCO Series 300 Automatic Transfer Switch: Outline and Mounting Dimensions (225-400 Amps) Comprehensive technical document detailing the outline and mounting dimensions for ASCO Series 300 Automatic Transfer Switches, rated from 225 to 400 Amperes. Includes general notes, terminal specifications, and weight data for open-type, 2-pole, 3-pole, and 4-pole configurations.