Asco 3ADTS, Installation Manual

Installation 

Manual 

 3ATS & 3NTS J-design 260-600 A 

3ADTS & 3NDTS 150-600 A Transfer Switches

381333-404 B 

ASCO Power Technologies 

Page 1 

DANGER is used in this manual to warn of a 
hazard situation which, if not avoided, will result in 
death or serious injury. 

WARNING is used in this manual to warn of a 
hazardous situation which, if not avoided, could 
result death or serious injury. 

CAUTION is used in this manual to warn of a 
hazardous situation which, if not avoided, could 
result in minor or moderate injury. 

Rating Label 

Each transfer switch contains a rating label to define the loads 

and fault circuit withstand/closing ratings.  Refer to the label 

on the transfer switch for specific values. 

Do not exceed the values on the rating label. 
Exceeding the rating can cause person injury or 
serious equipment damage. 

An experienced licensed electrician must install the transfer 
switch. 

Installation 

These transfer switches are factory wired and tested.  
Installation requires mounting, connecting service cables, and 
connecting engine start and auxiliary control circuits (if 
required.).

Supporting Foundation 

The supporting foundation for the enclosure must be level and 
straight.  Refer to the applicable enclosure outline drawing 
included with the transfer switch for all mounting details 
including door opening space. 

If bottom cable entry is used, the foundation must be prepared 
so that the conduit stubs are located correctly.  Refer to the 
enclosure outline drawing for specified area and location.  
Provide cable bending space and 1 inch minimum clearance to 
live metal parts.  When a concrete floor is poured, use 
interlocking conduit spacer caps or a wood or metal template 
to maintain proper conduit alignment. 

Mounting 

Refer to the outline and mounting diagram and mount the 
transfer switch according to details and instructions shown on 
the diagram.  Mount it vertically to a rigid supporting 
structure.  Level all mounting points by using flat washers 
behind the holes to avoid distortion of the transfer switch. 

Protect the transfer switch from construction grit 
and metal chips to prevent malfunction or 
shortened life of the transfer switch. 

381333-404 B

INSTALLATION 
Mounting .......................................................... 1
Power Connections ......................................... 2
Engine Starting Contacts ................................. 2

FUNCTIONAL TEST 
1- Manual Operation ........................................ 3
2- Voltage Checks ........................................... 5
3- Electrical Operation ..................................... 6

TESTING & SERVICE 
Transfer Test ................................................... 7
Preventive Maintenance .................................. 7
Manual Load Transfer ..................................... 7

TROUBLESHOOTING .................................... 8

Table of Contents 

Refer to the outline and wiring drawings provided 
with the 3ATS, 3NTS, 3ADTS, or 3NDTS for all 
installation and connection details and accessories.

Refer to 

User’s Guide 381333-400

 for the Group 

G Controller status display messages, time delays, 
pickup and dropout settings, and adjustments.