Asco 917 - User Manual

Questions and Answers

A
Alexa MirandaAug 6, 2025
Why does my Asco RC Switch close and open repeatedly?
- A
  Allison MolinaAug 6, 2025
  If your Asco RC Switch closes and opens repeatedly, it might be due to overlapping contacts in the control station. Ensure that the control station isn't simultaneously requesting the RC switch to both close and open. Correcting the control station setup should resolve this issue.
R
rosemichaelAug 11, 2025
What to do if Asco RC Switch tries to open or close, but cannot?
- K
  kendra59Aug 12, 2025
  If your Asco RC Switch attempts to open or close but is unable to do so, the issue might stem from low voltage. Verify the control wire size and the distance of the line run, referencing Table D on page 5. Also, if a transformer is integrated within the control line, ensure it meets the required VA burden, consulting Table E on page 5.
R
russell16Aug 17, 2025
What causes Asco RC Switch to close or open very quickly with excessive noise?
- R
  Rebecca VazquezAug 17, 2025
  If your Asco RC switch closes or opens rapidly and produces excessive noise, it could be due to high voltage. To resolve this, consider changing the control supply or replacing the RC switch.
J
john04Aug 25, 2025
What to do if Asco RC switch does not close when control station is closed?
- S
  Stephanie LucasAug 25, 2025
  If the Asco RC switch fails to close when the control station is closed, and there's no voltage present, inspect the control station contacts, control wiring, supply fuses, and any optional accessories.
S
Susan KaiserAug 29, 2025
What to do if Asco RC switch does not close when control station is opened?
- J
  Joseph WilliamsAug 29, 2025
  If the Asco RC switch fails to close when the control station is opened, and there's no voltage present, inspect the control station contacts, control wiring, supply fuses, and any optional accessories.

Summary

Installation

Mounting

Details on how to physically attach the RC switch for proper operation.

Line and Load Connections

Instructions for connecting power and load wires to the RC switch terminals.

Optional Accessories

Auxiliary Contacts

Information on auxiliary contacts 14H and 14HA for remote indication.

Control Modules and Operation

Details on control modules 47, 48, 49 and their functional behavior.

Troubleshooting and Support

Manual Operation

Instructions for manually operating the RC switch when power is disconnected.

Parts and Conversion

Information on ordering replacement parts and conversion kits for modification.

Outline Diagrams

Standard RC Switches Outline

Outline dimensions and mounting details for standard RC switches.

N;O & N;C RC Switches Outline

Outline dimensions and mounting details for N/O & N/C RC switches.

Outline Diagrams with Accessories

N;O & N;C Outline Diagrams with Accessories

Wiring Diagrams

Standard RC Switches Wiring

Wiring diagrams illustrating connections for standard RC switches.

N;O & N;C RC Switches Wiring

Wiring diagrams illustrating connections for N/O & N/C RC switches.

Wiring Diagrams with Accessories

ACC. 52 Control Line Fuse(s)

Details on accessory 52 control line fuses and their application.

N;O & N;C Wiring Diagrams with Accessories

Enclosure Outline and Mounting

The ASCO 917 & 918 Remote Control Switches are electromechanical devices designed for controlling lighting and general-purpose loads. These switches are UL-508 listed and available in various pole configurations, from 2 to 12 pole single throw double break, and 2 to 6 pole normally open and normally closed (N/O & N/C) configurations. Control voltages range from 120 to 480 V ac.

Function Description:

The ASCO 917 Remote Control (RC) Switches are primarily rated for 20 amperes non-HID lighting loads and 30 amperes general purpose. The ASCO 918 RC Switches are specifically designed for HID (high intensity discharge) loads, such as sodium vapor, mercury vapor, and metal halide lighting, with a control voltage limited to 277 V. They are rated for 30 amperes for standard ballast loads. The switches operate by momentarily energizing a single coil operator mechanism, which mechanically holds the contacts in either the open or closed position. The main contacts are shown in the open position when the control line is de-energized, but the switch is shipped with contacts closed. Line and load terminals are reversible.

Important Technical Specifications:

Current Ratings (Continuous):
- ASCO 917: 30 A (General), 20 A (Standard Ballast, Tungsten)
- ASCO 918: 30 A (General, Standard Ballast), 20 A (Tungsten)
Voltage Ratings (Main Contacts):
- 1-phase: 347 V ac
- 3-phase: 600 V ac
- Tungsten: 250 V ac
DC Voltage and Current Ratings:
- General: 20 A continuous
- 2 in Series: 125 V dc
- 3 in Series: 250 V dc
Withstand Current Ratings (Symmetrical Amperes RMS):
- 250 V ac: 22,000 A (with 30 A max breaker)
- 480 V ac: 14,000 A (with 30 A max breaker)
- 600 V ac: 10,000 A (with 30 A max breaker)
Control Voltage: 110-120 V, 208-240 V, 265-277 V, 347 V, 440-480 V (50-60 Hz). Note: 277 V maximum control voltage for ASCO 918.
Coil Inrush Current (RMS):
- 120 V: 5.0 A
- 240 V: 2.5 A
- 277 V: 2.2 A
- 347 V: 1.8 A
- 480 V: 1.3 A
Minimum Control Circuit Fuse Sizes (RMS):
- 120 V: 2.0 A
- 240 V: 1.0 A
- 277 V: 1.0 A
- 347 V: 0.75 A
- 480 V: 0.5 A
Wire Sizes:
- Line, Load, and Control Connections (L, O, C): #10 to #18 AWG Copper Wire.
- Control Module Connections (Acc. 47, 48, 49): #12 to #22 AWG Copper Wire.
Torque Specifications:
- Terminal clamp screws: 18 inch-pounds.
- Control module barrier screw type terminals: 12 inch-pounds.
Weight:
- 2-6 Poles: 2.0 lbs (0.91 kg)
- 8-12 Poles: 2.7 lbs (1.2 kg)

Usage Features:

Installation: The switches are pre-tested and ready for use. Installation involves mounting and connecting service cables and control circuit wires, and should be performed by a licensed electrician. They can be mounted in any position, but vertical mounting is typical. Mounting holes accept #10 screws for open-type switches and 1/4-inch diameter screws for enclosure mounting.
Control Line Distance: The manual provides a table (Table D) for maximum distances and minimum wire sizes for control lines between a control station and the RC switch, to ensure proper switch operation. These distances can be extended using Control Modules.
Overcurrent Protection: Overcurrent protective devices for the control circuit must be installed in accordance with applicable electrical codes.
Auxiliary Contacts (Optional Accessories 14H, 14HA): These contacts are installed on the left side of the RC switch and operate with the main contacts to provide remote indication of the switch position (closed or open). Each auxiliary contact is a form C, SPDT contact rated 10 amps at 277 V ac. Accessory 14H provides one contact, and 14HA provides two.
Control Modules (Optional Accessories 47, 48, 49): These modules are connected and mounted on the bottom or right side of the RC switch.
- Accessory 47 (Two-Wire Control): Requires a single-pole, maintained-type control station. The module must be energized to close the RC switch and de-energized to open it.
- Accessory 48 (Three-Wire Control): Requires a single-pole, double-throw, momentary-type control station. One terminal energizes to close, another to open.
- Accessory 49 (Form 3 Start-Stop Control): Requires one normally-closed and one normally-open separate control stations. The module must be energized to close and de-energized to open.
- Each control module is voltage-specific (12 V, 24 V, 120 V, 240/277 V ac/dc).
918 Coil Circuit: ASCO 918 RC Switches include an electronic circuit board specifically designed for HID lighting applications. This component should not be disconnected or removed.

Maintenance Features:

Troubleshooting: A dedicated troubleshooting section helps diagnose common issues such as the switch not closing/opening, repeated closing/opening, or excessive noise. It provides steps to check control voltage, control station contacts, wiring, and supply fuses.
Manual Operation: A #8-32 screw (1 1/2 inches long) can be used for manual operation. One is supplied in all replacement parts kits requiring manual operation. Before manual operation, all power and control circuits must be disconnected and verified de-energized with a voltmeter. The screw is inserted into the center of the coil and turned clockwise to engage the cam/core. Pulling the screw outward opens contacts, pushing it inward closes them.
Replacement Parts: Main contact blocks and operator coils are available in kit form. When ordering, the Serial No. and Catalog No. from the RC switch nameplate are required. Instructions for part replacement are included in kits and are also available separately (Service Bulletin 381339-021).
Conversion Kits: These kits are available for field or distributor modification to change pole configuration, control voltage, control modules, and auxiliary contacts.