Guidelines for the Surge Protective Devices Used in ICP UL Certification Requirement Decision [Historical Reference]

Citel Logo

Guidelines for the Surge Protective Devices Used in
ICP UL Certification Requirement Decision
[Historical Reference]

UL508A Main
UL508A Industrial Control Panel (ICP)

This Certification Decision is prepared and published by UL.
It is normative for the applicable UL Product Certification Program(s);
However, it is currently not part of the UL Standard(s) referenced below.

Product Category (CCN):NITW
Standard Number:Standard for Industrial Control Panels
Edition Date:December 20, 2013
Edition Number:2
Section / Paragraph Reference:Sections 2.48-2.52, 36.3, 47.1, 75.44, 75.8, Table SA1.1, Table SA1.2 and SB4.2
Subject:Surge Protective Devices (SPDs) for use in Industrial Control Panels

DECISION

2.48 SURGE PROTECTIVE DEVICE (SPD)

A device composed of at least one non-linear component and intended for limiting surge voltages on equipment by diverting or limiting surge current and is capable of repeating these functions as specified. SPDs were previously known as Transient Voltage Surge Suppressors or secondary surge arresters.

2.49 ONE-PORT SPD

A SPD having provisions (terminals, leads, plug) for connection to the ac power circuit but no provisions (terminals, leads, receptacles) for supplying current to ac power loads.

2.50 TWO-PORT SPD

A SPD having provisions (terminals, leads, plug) for connection to the ac power circuit and provisions [terminals, leads, receptacles(s)] for supplying current to one or more ac power loads. SPDs provided with a minimum of two adjacent terminals for each circuit conductor may be considered and tested as a two-port SPD.

2.51 SURGE PROTECTIVE DEVICE (SPD) TYPE DESIGNATIONS –
SPD Type designations are as follows:

TYPE 1Permanently connected SPDs intended for installation between the secondary of the service transformer and the line side of the service equipment overcurrent device, as well as the load side, including watt-hour meter socket enclosures and intended to be installed without an external overcurrent protective device.
TYPE 2Permanently connected SPDs intended for installation on the load side of the service equipment overcurrent device - including SPDs located at the branch panel.
TYPE 3Point of utilization SPDs, installed at a minimum conductor length of 10 meters (30 feet) from the electrical service panel to the point of utilization, for example cord connected, direct plug-in, receptacle type and SPDs installed at the utilization equipment being protected. The distance of 10 meters (30 feet) is exclusive of conductors provided with or used to attach SPDs.
TYPE 4
COMPONENT ASSEMBLIES
Component assembly consisting of one or more Type 5 components together with a disconnect (integral or external) or a means of complying with the limited current tests.
TYPE 1, 2, 3
COMPONENT ASSEMBLIES
Consists of a Type 4 component assembly with internal or external short circuit protection. These types are tested and rated based on the intended application as either Type 1, 2 or 3 SPD’s.
TYPE 5Discrete component surge suppressors, such as MOVs that may be mounted on a PWB, connected by its leads or provided within an enclosure with mounting means and wiring terminations.

2.52 SURGE PROTECTIVE DEVICE (SPD) ELECTRICAL RATINGS

2.52.1NOMINAL DISCHARGE CURRENT (In)Peak value of the current, selected by the manufacturer, through the SPD having a current waveshape of 8/20 where the SPD remains functional after 15 surges.
2.5.2.2MAXIMUM CONTINUOUS OPERATING VOLTAGE (MCOV) ratingThe maximum continuous operating voltage that may be applied between the terminals of a surge protective device (SPD).
2.5.2.3NORMAL OPERATING VOLTAGE RATINGThe voltage rating assigned to a SPD by the manufacturer. For a SPD, other than a Component-SPD, it is generally equal to the nominal value of the voltage of the circuit (for example, 120, 208, 240, 347, 480, or 600 Vrms).

36.3 Surge protective devices (SPDs)

36.3.1An SPD shall comply with the requirements in the Standard for Surge Protective Devices, UL 1449.
36.3.2The normal operating voltage rating and MCOV of the SPD shall not be less than the rated circuit Line-to-Line (full phase) voltage.
36.3.4Where provided, a SPD shall be connected to each ungrounded conductor. The conductors used to connect the SPD to line and to ground shall not be longer than required and shall not have more bends than required by the construction. Line and ground connecting conductors to a SPD shall not be smaller than 14 AWG (2.1 mm2).
36.3.4A SPD marked with a slash voltage rating shall only be used in a circuit where the source is solidly grounded as noted in 16.3 when voltage is from transformer or power supply provided within the industrial control panel, or by marking the slash voltage rating on the industrial control panel nameplate in accordance with 49.6(a), as appropriate. A SPD marked for use on a delta system, such as "600V delta", can be used on either a wye or a delta system.

47.1 Surge protective devices (SPDs)

47.1.1A SPD used for overvoltage protection shall comply with the requirements in the Standard for Surge Protective Devices, UL 1449.
47.1.1.1The normal operating voltage rating and MCOV of the SPD shall not be less than the rated circuit Line-to- Line (full phase) voltage
47.1.1.2A protector for data communications and fire-alarm circuits shall comply with the Standard for Protectors for Data Communications and Fire-Alarm Circuits, UL 497B.
47.1.2An electromagnetic interference filter, such as an EMI, RFI, or line filter, shall comply with the Standard for Electromagnetic Interference Filters, UL 1283.
47.1.3A dry-type capacitor that is placed across the line, without other impedances in series, shall comply with the Dielectric Voltage Withstand Test in the Standard for Industrial Control Equipment, UL 508.
47.1.4A capacitor, an axial lead diode, a transient voltage surge suppressor, and an electromagnetic interference filter shall have a rated voltage not less than the rated circuit voltage. An electromagnetic interference filter shall have a current rating that is not less than the sum of the current ratings of all connected loads or not less than the ampacity of the internal wiring conductors.

75.4.4: A disconnecting means for SPDs, ground fault equipment, and the control circuit for power operated disconnecting means shall not be counted towards the number of disconnecting means allowed by 75.4.3.

75.8 Components on the supply side of the disconnecting means

75.8.1Other than as specified in 75.8.2 – 75.8.4, components shall not be located on the line side of the service disconnecting means.
75.8.2A meter socket shall comply with the Standard for Meter Sockets, UL 414 and is able to be located on the line side of the service disconnecting means.
75.8.3Control circuits for power operable service disconnecting means, or for ground fault protection covered by 75.6, are able to be connected to the line side of the service disconnecting means when provided with disconnecting means and overcurrent protection.
75.8.4A Type 1 SPD shall comply with the requirements in the Standard for Surge Protective Devices, UL 1449.

Table SA1.1 – (Only that part of the table being revised is shown)

UL508A Section/Paragraph Reference
Section 36 - Miscellaneous power devices meeting component selection requirements
36.3.1
updated
to 36.4.1
in ed. 2020
[Recognized]
Surge Protective Devices
UL 1449VZCA2SPDs that are outside the guidelines of Table 2 must be procedure described
36.3.1
updated
to 36.4.1
in ed. 2020
[Listed]
Surge Protective Devices
UL 1449VZCAType 1, 2 or 3 SPDs that are outside the guidelines of Table 2 must be procedure described
Section 47 - Surge control devices meeting component selection requirements
UL508A
Paragraph
reference
Component descriptionUL StandardCategory
control
number(s)
Notes
47.1.1[Recognized]
Surge Protective Devices
UL 1449VZCA2SPDs that are outside the guidelings of Table 2 must be procedure described
47.1.1[Listed]
Surge Protective Devices
UL 1449VZCAType 1, 2 or 3 SPDs that are outside the guidelines of Table 2 must be procedure described
47.1.3[Listed]
isolated Loop Circuit Protectors
UL 479BQVGQ-
47.1.3[Recognized]
isolated Loop Circuit Protectors
UL 479BQVGQ2Procedure described
Section 75 - Service Equipment Use - components meeting specific selection requirements
UL508A
Paragraph
reference
Component descriptionUL StandardCategory
control
number(s)
Notes
75.8.4Surge
Protective
Devices
UL 1449VZCAType 1 SPD Only

Table SA1.2 - Use of Surge Protective Devices

Type of Surge Protective Device (SPD) - One port only*
Listed Type 1Listed Type 2Listed Type 3R/C
Type 4
Component
Assembly
R/C Type 5
Location of the SPD
Service Equipment Supply Side of Overcurrent Protectionwzzzz
Service Equipment Load Side of Overcurrent Protectionwwzzz
Non-Service Equipment Feeder or Branch Circuitswwwzz
Isolated Control Circuitswwwww
Ratings
Service Equipment Supply Side of Overcurrent ProtectionVbxzzzz
In cyzzzz
Service Equipment Load Side of Overcurrent ProtectionVbxxzzz
In cy10kAzzz
Non-Service Equipment Feeder or Branch CircuitsVbxxxzz
In cyyyzz
Isolated Control CircuitsVbxxxxx
In cyyy3kA3kA
NOTES
(1)A "w" indicates an allowable location for the SPD.
(2)An "x" indicates indicates a Normal Operating Voltage Rating is required as specified in footnote "b" below.
(3)A "y" indicates indicates a Nominal Discharge Current Rating as specified in footnote "c" below is not required.
(4)A "z" indicates the SPD nees further evaluation to determine suitability and Procedure description is required.
(a)A Two-Port SPD shall be Listed and comply with the ratings specified above for the intended application. In addition, it shall have an appropriate short circuit current rating (SCCR) rating.
(b)V - Normal Operating Voltage Rating - Operating Voltage and MCOV ratings shall be equal to or greater than the applied circuit Line-to-Line (full phase) voltage.
(c)In (NDC) - Nominal Discharge Current - Amount of peak current "forced" through the device during Surge Testing.

Overview [UPDATED APRIL 13, 2020]

In North America, UL approval provides independent 3rd Party certification that a product has been tested by Underwriters Laboratories (UL) or another Nationally Recognized Testing Laboratory (NRTL) and meets all necessary electric code safety requirements as well as industry benchmarks.

On April 13, 2020, UL released a UL508A supplement document titled "REQUIREMENTS FOR COMPONENTS USED IN INDUSTRIAL CONTROL PANELS" that was published with the intent to help control panel builders determine the requirements for components when used in industrial control panels. The document replaces what was Supplement SA in the Second Edition of UL508A, and subsequently Appendix C in the Third Edtition of UL508A. It supersedes the previous verion of this document dated October 21, 2019.

Remote VFD Control Panel

UL, in the form of the UL inspector, will carefully consider many factors while determing the fitness of the Surge Protective Device (SPD) for the equipment that is being evaluated for UL compliance. It is critically important to understand the process that UL will use to evaluate the SPD according to UL508A.

Each component belongs to individual Category that describes the specific requirements of the component. In a UL508A Industrial Control Panel, the Surge Protective Device will be evaluated based on Sections 36, 47, and 75. These sections are referenced in Table 1 of the Supplement document.

Table 1 - Components that comply with specific requirements

UL508A Section/Paragraph Reference
Section 36 - Miscellaneous power devices meeting component selection requirements
UL508A
Paragraph
reference
Component descriptionUL StandardCategory
control
number(s)
Notes
36.4.1Recognized Surge
Protective
Devices
UL 1449VZCA2SPDs that are outside the guidelings of Table 2 must be procedure described
36.4.1Listed Surge
Protective
Devices
UL 1449VZCAType 1, 2 or 3 SPDs that are outside the guidelines of Table 2 must be procedure described
Section 47 - Surge control devices meeting component selection requirements
UL508A
Paragraph
reference
Component descriptionUL StandardCategory
control
number(s)
Notes
47.1.1Recognized Surge
Protective
Devices
UL 1449VZCA2SPDs that are outside the guidelings of Table 2 must be procedure described
47.1.1Listed Surge
Protective
Devices
UL 1449VZCAType 1, 2 or 3 SPDs that are outside the guidelines of Table 2 must be procedure described
47.1.3Listed isolated Loop Circuit ProtectorsUL 479BQVGQ-
47.1.3Recognized isolated Loop Circuit ProtectorsUL 479BQVGQ2Procedure described
Section 75 - Service Equipment Use - components meeting specific selection requirements
UL508A
Paragraph
reference
Component descriptionUL StandardCategory
control
number(s)
Notes
75.8.4Surge
Protective
Devices
UL 1449VZCAType 1 SPD Only

The first step in determining the acceptability of the SPD for a given application or piece of equipment is to consider the UL SPD Type. This is the case for UL 508A as well as all other UL Listed equipment. This first level compliance is based on the UL Approval (LISTED UL logo png or RECOGNIZED UR logo png ) of the SPD or UL SPD Type and it’s Suitable Ratings. This means that the SPD has met all safety, performance, environmental and electrical system ratings of the application.

If any of these criteria are not fully met, it will require a Procedure Description, a File Update and/or Additional Testing. These actions will require additional costs that may be substantial. For this reason, it is in the interest of the specifier to use UL LISTED UL logo png SPD (Type 1 or Type 2) to eliminate any uncertainty or to make sure the UL RECOGNIZED UR logo png SPD (Type 1CA, Type 2CA, Type 4CA, Type 5) is selected at the initial UL evaluation of the control panel or at the submittal of the equipment to UL for compliance testing.

Table 2 - Use of Surge Protective Devices

Type of Surge Protective Device (SPD) - One port only*
Listed Type 1Listed Type 2Listed Type 3R/C
Type 4
Component
Assembly
R/C Type 5
Location of the SPD
Service Equipment Supply Side of Overcurrent Protectionwzzzz
Service Equipment Load Side of Overcurrent Protectionwwzzz
Non-Service Equipment Feeder or Branch Circuitswwwzz
Isolated Control Circuitswwwww
Ratings
Service Equipment Supply Side of Overcurrent ProtectionVbxzzzz
In cyzzzz
Service Equipment Load Side of Overcurrent ProtectionVbxxzzz
In cy10kAzzz
Non-Service Equipment Feeder or Branch CircuitsVbxxxzz
In cyyyzz
Isolated Control CircuitsVbxxxxx
In cyyy3kA3kA
NOTES
(1)A "w" indicates an allowable location for the SPD.
(2)An "x" indicates indicates a Normal Operating Voltage Rating is required as specified in footnote "b" below.
(3)A "y" indicates indicates a Nominal Discharge Current Rating as specified in footnote "c" below is not required.
(4)A "z" indicates the SPD nees further evaluation to determine suitability and Procedure description is required.
(a)A Two-Port SPD shall be Listed and comply with the ratings specified above for the intended application. In addition, it shall have an appropriate short circuit current rating (SCCR) rating.
(b)V - Normal Operating Voltage Rating - Operating Voltage and MCOV ratings shall be equal to or greater than the applied circuit Line-to-Line (full phase) voltage.
(c)In (NDC) - Nominal Discharge Current - Amount of peak current "forced" through the device during Surge Testing.

To help control panel builders select the right SPD based on the UL508A Industrial Control Panels standard, CITEL Citel C , in consultation with Underwriters Laboratories (UL), has made this quick reference table. If you have any questions on how to use this table or any technical and compliance questions, please contact CITEL.

Approval Considerations based on UL SPD Type

UL
Mark
UL1449
SPD Type
Suitable
Ratings
Procedure
Described
File
Update or
Additional
Testing
Notes
UL logo png 1

2
YesNoNoThe only requirement is that the SPD must match electrical and environmental ratings of the UL 508A Control Panel.

A UL field inspection of the control panel with the SPD installed is required as a part of a standard follow-up service visit.
UR logo png 1CA

2CA

4CA

5
YesYesYesYes – All UL recognized SPD’s require a UL engineering evaluation of the SPD’s existing UL1449 E–file.

This will result, at a minimum, in a cost to update the UL file and may also require testing that would result in additional costs.

CITEL Citel C UL LISTED UL logo png SPD meeting all requirements of UL508A

The following is a list of products for each section. They are UL Listed SPD and require only that they meet the "Suitable Rating" of the control panel. They can be used in all UL locations including,

  • Service Equipment Supply Side of Overcurrent Protection
  • Service Equipment Load Side of Overcurrent Protection
  • Non-Service Equipment Feeder or Branch Circuits
  • Isolated Control Circuits
UL508A
Paragraph
reference
Component
description
UL StandardCategory
control
number(s)
SystemPart #Link
36.4.1
Miscellaneous
power devices
Listed
Surge
Protective
Devices
UL 1449VZCA120Vac
1-Phase
2W+G
Single Phase
DS72US-120S/G DS72US-120S/G
120-240Vac
1-Phase
2W+G
Single Phase
DS72US-240T/NN DS72US-240TNN
120/240Vac
1-Phase
3W+G
Split Phase
DS73US-120T/G DS73US-120T-G
120/208Vac
3-Phase
4W+G
Wye
DS74US-120Y/G DS74US-277Y/G
277/480Vac
3-Phase
4W+G
Wye
DS74US-277Y/G DS74US-277Y/G
480Vac
3-Phase
3W+G
Delta
DS74US-480D DS74US-480D
47.1.1
Surge
control devices
Listed
Surge
Protective
Devices
UL 1449VZCA120Vac
1-Phase
2W+G
Single Phase
DS72US-120S/G DS72US-120S/G
120-240Vac
1-Phase
2W+G
Single Phase
DS72US-240T/NN DS72US-240TNN
120/240Vac
1-Phase
3W+G
Split Phase
DS73US-120T/G DS73US-120T-G
120/208Vac
3-Phase
4W+G
Wye
DS74US-120Y/G DS74US-277Y/G
277/480Vac
3-Phase
4W+G
Wye
DS74US-277Y/G DS74US-277Y/G
480Vac
3-Phase
3W+G
Delta
DS74US-480D DS74US-480D
47.1.3
Surge
control devices
Listed
isolated Loop
Circuit Protectors
UL 479BQVGQRS422 DLAS-06D3 DLAS1-24D3
RS232
RS485
DLAS-12D3 DLAS1-24D3
4-20mA
Current Loop
DLAS-24D3 DLAS1-24D3
48Vdc DLAS-48D3 DLAS1-24D3
75.8.4
Service
Equipment Use
Surge
Protective
Devices
UL 1449VZCA120Vac
1-Phase
2W+G
Single Phase
DS72US-120S/G DS72US-120S/G
120-240Vac
1-Phase
2W+G
Single Phase
DS72US-240T/NN DS72US-240TNN
120/240Vac
1-Phase
3W+G
Split Phase
DS73US-120T/G DS73US-120T-G
120/208Vac
3-Phase
4W+G
Wye
DS74US-120Y/G DS74US-277Y/G
277/480Vac
3-Phase
4W+G
Wye
DS74US-277Y/G DS74US-277Y/G
480Vac
3-Phase
3W+G
Delta
DS74US-480D DS74US-480D

Citel Logo
10108 USA Today Way
Miramar, FL 33025 USA
Contact us to develop a surge mitigation solution for your application

www.citel.us

Where to purchase Citel SPDs