HydroFlo craftsmen take pride in the design and fabrication of every control panel we build. To that end, HydroFlo builds every panel to UL 508A Specifications. UL 508 certification is available upon request. To show you just how detailed the specification is, we have listed the Table of Contents from UL-508A (see below).

If you have been in the field much, I am sure that you are familiar with panels that look like a half wound ball of string. This type of wiring is extremely dangerous and makes troubleshooting the system nearly impossible. 

With all HydroFlo’s panels, the wiring is color coded and run in raceways, and all of the terminal blocks and wiring are always clearly labeled and neatly organized. All field connections are terminated in one common area. This makes the installation of a HydroFlo main control panel, a remote control panel, or terminal box quick and easy. The care we take in the crafting of our control panels makes maintenance and troubleshooting easier, ultimately resulting in lowered installation cost.

UL-508A Table of Contents

• Cover
• Transmittal
• Table of Contents
• UL Foreword
• Body
  • PART 1 - GENERAL USE INDUSTRIAL CONTROL PANELS
    • INTRODUCTION
    • 1 Scope
    • 2 Glossary
    • 3 Undated References
    • 4 Components
    • 5 Units of Measurement
    • 6 Terminology
    • CONSTRUCTION
      • ALL PANELS
    • 7 General
    • 8 Protection Against Corrosion
    • 9 Support and Securement of Live Parts
    • 10 Spacings
    • 11 Conduit Bushings
    • 12 Insulating Barriers
    • 13 Insulating Materials
    • 14 Grounding - General
    • 15 Grounding - Size of Terminal or Bonding Conductor
    • 16 Transformer and Power Supply Secondary Grounding
    • 17 Identification of Grounding and Grounded Circuit Conductors and Terminals
      • ENCLOSED PANELS
    • 18 Enclosures
    • 19 Enclosure Openings
    • 20 Accessibility of Live Parts
    • 21 Ventilation Openings
      • 21.1 General
      • 21.2 Location of ventilation opening
      • 21.3 Construction
    • 22 Barriers Used with Ventilation Openings
    • 23 Observation Windows
    • 24 Bonding
    • 25 Wire Bending Space
    • 26 Enclosure Environmental Control Devices
      • 26.1 General
      • 26.2 Enclosure fans
      • 26.3 Enclosure air conditioner
      • 26.4 Enclosure heater
      • 26.5 Air filters
      • 26.6 Enclosure thermal insulation
    • 27 Enclosure Maintenance Lighting
      • 27.1 General
      • 27.2 Component requirements
      • 27.3 Circuit requirements
      • POWER CIRCUITS
    • 28 Field Wiring
      • 28.1 General
      • 28.2 Component requirements
      • 28.3 Sizing
      • 28.4 Separation of circuits
      • 28.5 Cord-connected equipment
      • 28.6 Receptacles
    • 29 Internal Wiring
      • 29.1 General
      • 29.2 Conductor requirements
      • 29.3 Wiring methods
      • 29.4 Routing of internal wiring
      • 29.5 Separation of circuits
      • 29.6 Sizing
    • 30 Disconnect Switches
      • 30.1 Component requirements
      • 30.2 Sizing of disconnect switch
      • 30.3 Location
      • 30.4 Mechanical operating mechanism
    • 31 Branch Circuit Protection
      • 31.1 Component requirements
      • 31.2 Location
      • 31.3 Sizing of branch circuit protection for single motor circuit
      • 31.4 Sizing of branch circuit protection for motor groups
      • 31.5 Receptacles
      • 31.6 Sizing of branch circuit protection for heater loads
      • 31.7 Sizing of branch circuit protection for appliance loads
      • 31.8 Sizing of branch circuit protection for lighting loads
    • 32 Overcurrent Protection of Feeder
      • 32.1 Component requirements
      • 32.2 Location
      • 32.3 Sizing of overcurrent protection
    • 33 Load Controllers
      • 33.1 Component requirements
      • 33.2 Sizing/rating of load controllers
      • 33.3 Location
      • 33.4 Reversing motor controllers
      • 33.5 Wye-delta motor controllers
    • 34 Overload Protection of Motor Loads
      • 34.1 Component requirements
      • 34.2 Sizing of overload relay
      • 34.3 Location
    • 35 Power Transformers
      • 35.1 Component requirements
      • 35.2 Sizing of overcurrent protection for power transformer
      • 35.3 Location
    • 36 Other Circuit Components
      • 36.1 Capacitors
      • 36.2 Resistors
      • 36.3 Surge control devices
      • CONTROL CIRCUITS
    • 37 Field Wiring Terminals
      • 37.1 Component requirements
      • 37.2 Sizing
      • 37.3 Field wiring terminals of a low-voltage limited energy circuit
      • 37.4 Field wiring terminals of Class 2 circuits
      • 37.5 Separation of circuits
      • 37.6 Receptacles
      • 37.7 Flexible cords
    • 38 Internal Wiring
      • 38.1 Component requirements
      • 38.2 Sizing of internal control circuit conductors
      • 38.3 Wiring methods, wire routing, and separation of circuits for internal wiring of a control circuit
    • 39 Disconnecting Means
    • 40 Overcurrent Protection
      • 40.1 Component requirements
      • 40.2 Location of overcurrent protective devices
      • 40.3 Sizing of overcurrent protection
    • 41 Sizing of Overcurrent Protection
    • 42 Overcurrent Protection -
      • 42.1 Control transformers
      • 42.2 Power supplies
      • 42.3 Other isolated secondary sources
    • 43 Low-Voltage Limited Energy Circuits
      • 43.1 Component requirements
      • 43.2 Secondary side requirements
    • 44 Class 2 Circuits
      • 44.1 Component requirements
      • 44.2 Secondary side requirements
    • 45 Switching Devices
      • 45.1 Component requirements
      • 45.2 Sizing/ratings of control circuit switching devices
      • 45.3 Location
      • 45.4 Undervoltage protection
    • 46 Loads
      • 46.1 Component requirements
      • 46.2 Location
      • 46.3 Rating of control circuit load
    • 47 Miscellaneous Devices
      • 47.1 Surge control devices
      • 47.2 Resistors
    • 48 Pneumatic Switching Devices
    • RATING
    • 49 Supply Ratings
    • 50 Individual Load Ratings
    • 51 Ratings for Control Circuit Outputs
    • MARKINGS
    • 52 General Markings
    • 53 Enclosure Markings
    • 54 Field Wiring Terminal Markings
    • 55 Cautionary Markings
    • 56 Fuseholder Markings
    • 57 Switch Markings
    • 58 Overload Relay Heater Table Markings
    • 59 Receptacle Markings
    • 60 Field Provided Components
    • 61 Schematic Wiring Diagrams
  • PART 2 - SPECIFIC USE INDUSTRIAL CONTROL PANEL TYPES
    • ENCLOSURES
    • 62 General
    • 63 Construction
      • 63.1 Metal thickness
      • 63.2 Covers and doors
      • 63.3 Corrosion protection
      • 63.4 Enclosure openings
      • 63.5 Ventilation openings
      • 63.6 Observation windows
    • 64 Markings
    • INDUSTRIAL MACHINERY
    • 65 General
    • 66 Construction
      • 66.1 Enclosures
      • 66.2 Electrical assembly
      • 66.3 Grounding
      • 66.4 Field wiring -
      • 66.5 Internal wiring -
      • 66.6 Disconnecting means
      • 66.7 Branch circuit protection
      • 66.8 Motor controllers
      • 66.9 Internal wiring of control circuit
      • 66.10 Overcurrent protection of common control circuit
      • 66.11 Overcurrent protection of control transformer
      • 66.12 Operator controls
    • 67 Markings
      • 67.1 Nameplate markings
      • 67.2 Operator controls
      • 67.3 Components
      • 67.4 Cautionary marking
    • CRANE CONTROL
    • 68 General
    • 69 Glossary
    • 70 Construction
      • 70.1 Field wiring terminals of power circuits
      • 70.2 Internal wiring
      • 70.3 Disconnecting means
      • 70.4 Branch circuit protection
      • 70.5 Motor overload protection
      • 70.6 Field wiring of control circuits
      • 70.7 Overcurrent protection of control circuit
    • 71 Ratings
    • 72 Markings
    • SERVICE EQUIPMENT USE
    • 73 General
    • 74 Glossary
    • 75 Construction
      • 75.1 Grounding and bonding
      • 75.2 Spacings
      • 75.3 Field wiring terminals
      • 75.4 Disconnecting means
      • 75.5 Neutral disconnecting means
      • 75.6 Ground-fault protection
      • 75.7 Overcurrent protection
      • 75.8 Components on the supply side of the disconnecting means
    • 76 Ratings
    • 77 Markings
      • 77.1 Bonded neutral
      • 77.2 Insulated neutral
      • 77.3 Marking location
      • 77.4 Disconnects
      • 77.5 Ground-fault protection
    • 78 Installation Instructions
    • 79 Tests By The Manufacturer - Ground-Fault Protection Test
    • ELEVATOR CONTROL
    • 80 General
    • FLAME CONTROL
    • 81 General
    • 82 Construction
      • 82.1 Component requirements
      • 82.2 Spacings
      • 82.3 Internal wiring
      • 82.4 Location
      • 82.5 Separation of circuits
      • 82.6 Overcurrent protection
    • 83 Marking
    • MARINE USE
    • 84 General
    • 85 Construction
      • 85.1 Enclosures
      • 85.2 Autotransformer starters
      • 85.3 Insulating materials
      • 85.4 Branch circuit overcurrent devices
    • 86 Ratings
    • 87 Markings
    • AIR CONDITIONING AND REFRIGERATION EQUIPMENT
    • 88 General
    • 89 Glossary
    • 90 Construction
      • 90.1 Field wiring sizing -
      • 90.2 Disconnecting switches
      • 90.3 Branch circuit protection sizing - power circuits
      • 90.4 Load controllers -
    • 91 Ratings
    • 92 Marking
• SPECIFIC COMPONENT REQUIREMENTS
• SHORT CIRCUIT CURRENT RATINGS FOR INDUSTRIAL CONTROL PANELS
• APPENDIX A
• APPENDIX B
• Superseded List