Emerson 7ATB manual INSTALLATION continued, Bus Connections, Testing Power Conductors, Harnesses

INSTALLATION (continued)

De–energize the conductors before making any line or auxiliary circuitry connections. Be sure that Normal and Emergency line connections are in proper phase rotation. Place engine gen- erator starting control in the OFF position. Make sure engine generator is not in operation.

Bus Connections

If bus connection is used, use SAE grade 5 hardware to connect bus to appropriate terminal plates on bypass switching device. Wipe off bus surfaces before they are joined. If bus is dirty, gently clean surfaces with a non-flammable solvent. Avoid touching cleaned surfaces.

Testing Power Conductors

Do not connect the power conductors to the ATB until they are tested. Installing power cables in conduit, cable troughs, and ceiling-suspended hangers often requires considerable force. The pulling of cables can damage insulation and stretch or break the conductor’s strands. For this reason, after the cables are pulled into position, and before they are connected they should be tested to verify that they are not defective or have been damaged during installation.

Protect the switch from construction grit and metal chips to prevent malfunction or shortened life of the 7ATB switch.

Connecting Power Conductors

A Wiring Diagram is furnished with the ATB. All wiring must be made in accordance with the local codes. After the power cables have been tested, connect them to the appropriate terminal lugs on the Bypass Switch as shown on the wiring diagram provided with this ATB. Make sure that the lugs provided are suitable for use with the cables being installed. Standard terminal lugs are solderless screw type and will accept the wire sizes listed on the drawings provided with the ATB. Be careful when stripping insulation from conductors; avoid nicking or ringing the conductor. Remove surface oxides from conductors by cleaning with a wire brush. Follow conductor manufacturer’s instructions when aluminum conductor is used. Apply joint compound to conductor, then carefully wipe away excess compound. Tighten the cable lugs to the torque specified on the rating label.

Be sure that the Normal and Emergency power connections are in proper phase rotation.

Do not breathe cleaning solvent vapors.

Use SAE grade 5 hardware and tighten the bolted joints to the torque specified in Table 2-1.

The reliability of the connection depends on how clean and how tight the joint is.

Table 2-1. Tightening torque values for bolted joints.

Bolt Diameter	Recommended
(Grade 5 hardware)	Tightening Torque
in inches	in foot pounds
5/16	12
3/8	20
1/2	50
5/8	95

Harnesses

All internal connections are made at the factory. The bypass switch, transfer switch, and control panel are joined together by an interconnecting wire harness. The disconnect plugs are already engaged on enclosed switches. For open–type switches, the plugs must be engaged after installation is completed. Align harness plugs with sockets in the control and push them together until they are secure.

Engine Starting Contacts

and Auxiliary Circuits

The engine control contact signal connections and auxiliary circuits are located on terminal block TB as shown on the Wiring Diagram provided with the ATB. Connect the signal wires to the appropriate terminals.

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