Asco 920 - Installation; Mounting; Service Connections; Control Line Connections

INSTALLATION
1
To preve n t malfunc t i on or sh or t e n ed life, prote c t
the switch from construction grit and metal chips.
Mounting: Two Outline and Mounting Diagrams are
furnished; one for enclosed switches, the other for open–
type switches. Select the appropriate diagram and mount
the RC Switch (in any position). All mounting details
and instructions are shown on the diagram.
RC Swit ch es on subpanels must be mounted with
supplied insulator bushings and insulator pieces.
Be sure th e insulator pieces are behind the switch
and use th e ins u lat or bush i n gs under th e har d w ar e.
Figure 1. Required insulator bushings and backing
insulators for RC Switches mounted on subpanels.
Service Connections: For panel b oar d mou ntin g , the
extended bus plates provide both the mec h anic al support
and the electric al connec tion. Switches on sub panel s are
fur n is h ed with solderless lu gs for cop p er or alu minum wire.
Outline and Mounting Diagram l is ts wire siz es acc ep t ed .
Remove surface oxides from wires by cleaning with a wire
brush. When aluminum conductor is used, apply joint
com pou nd to conduc tor. Tig hten condu c tor and careful l y
wipe away excess comp oun d. Maintain proper electr ic al
cl ear anc e betw een live metal parts and groun ded metal .
Control Line Connections: Control circuit connections
designated L, O, C are supplied with clamp type
terminals. These terminals accept wire sizes #14–10
AWG Cu. Simply insert appropriate control wires and
tighten terminal clamp screws. See the W iring Diagram.
Tighten all electrical connections; refer to the
torque specified on the label on the RC Switch.
Table A lists the maximum distances and minimum wire
sizes t hat can be run between a control station and one
ASCO 920 switch.
TableA–LineRun
Min.
Wire Size
Maximum Distance (feet)
1
for these AC Control Voltages
W
i
r
e
S
i
z
e
AWG
120 V 208 V 240 V 277 V
14
12
10
750
1200
2000
1650
2600
4200
2760
4300
6900
3950
6350
10000
1
For ambient temperat ures to 40˚C.
Do not exceed these distances
forproperswitchoperation.
Line run can be ext ended by use of Auxiliary Control
Relays. See page 3.
Table B provides the ASCO 920 coil inrush current and
minimum control circuit fuse sizes.
Table B – Inrush Current / Minimum Fuse
A
m
p
s
Inrush Current / Fuse (amps)
2
for these AC Control Voltages
A
m
p
s
120 V 208 V 240 V 277 V 480 V
Inrush 11.3 5.15 6.4 7 7
Fuse 3 1.5 1.5 1.5 3
2
F use value listed will also protect ASCO 920
against abnormal operating conditions.
MAINTENANCE
Annual preventive maintenance will insure high
reliability and long life for the ASCO 920 R C Switch.
Keep the Switch clean. De–energize all sources, then
brush and vacuum away any excessive dust accumulation.
Maintain Switch Lubrication. Under normal service,
relubrication is not required. Renew factory lubrication
if switch is subjected to severe dust or abnormal
operating conditions, and i f t he coil is replaced. Only use
Lubrication Kit 625549; do not use oil or any other type
of lubricant.
Inspect Main Current–Carrying Contacts.
De–energize all sources, then remove cover to check
contact conditi on. Discolorati on or slight pitting does
not affect contact efficiency. Replace the contacts when
they become pitted, excessively worn, or appear to be
overheated.
Thearcchutesareheldinplacebythecover.
Ifthearcchutesareremoved,besuretheyare
put back in place with “top” visable. Make sure
the cover is fully seated before tightening the
cover screws. (Do not over–tighten).