November 7, 2003
SUMMARY OF REQUIREMENTS
The following is a brief summary of the new and revised paragraphs in the Standard for Industrial Control Equipment, UL 508, which have a future Effective Date of December 12, 2004 and the action that may be required to determine compliance.
TOPIC “A” - BUS BAR ACCESSORIES FOR USE WITH INDUSTRIAL CONTROL EQUIPMENT
Paragraphs General Subject and Comment
36.1 Requires bus bar accessory products intended to be installed on the line side of branch circuit protective devices to comply with spacing requirements in Table 76.3 of UL508.
76.12 Requires bus bar accessories that mount to the line side of self-protected combination motor controllers to comply with Table 36.1 and the terminals of the bus bar accessory to comply with Table 76.3 of UL508.
50.1.7, 50.1.8, Requires bus bar accessories for use on the line side of branch circuit protection to
50.1.9 comply with the short circuit test from UL845, Standard for Motor Control Centers, which includes tests to evaluate the bus structure alone and also with representative control devices connected. Bus bar accessories that are supported only by the line side of terminals of self-protected combination motor controllers and those for use on the load side of branch circuit protection, such as in a motor group installation, are short circuit tested with representative controllers and are not required to have the withstand test on bus bars alone.. All bus bar accessories are required to marked to indicate specific controllers with which they have been evaluated and with installation instructions describing the intended installation.
The new and revised requirements will impact Listed and Recognized bus bar accessories intended for use with industrial control equipment. These devices should be covered under the category for Miscellaneous Apparatus (NMTR) or (NMTR2) as appropriate. Bus bars found to be covered under categories other than NMTR/NMTR2 will be relocated accordingly.
Description of Action Required by Manufacturers:
1. Manufacturers of Listed and Recognized bus bar accessory products that will require modification of the construction, and/or markings, and those requiring short circuit testing to comply with the new and revised requirements and intending to continue Listing or Recognition after the effective date, are requested to provide a description of the proposed modifications to comply with these requirements to Underwriters Laboratories.
2. Manufacturers having products (described in item 1) that comply with the new and revised requirements without modification or testing and intending to continue Listing or Recognition after the effective date, are requested to provide data demonstrating compliance with these requirements to Underwriters Laboratories.
3. Manufacturers of Listed or Recognized products that are not bus bar accessories are not affected by these requirements and are asked to respond accordingly to Underwriters Laboratories.
TOPIC “B” – FLOAT AND PRESSURE OPERATED CONTROLLERS
Paragraphs General Subject and Comment
106.3 Float switch (cord-connected switch enclosed in float) enclosures shall comply with the water exposure and immersion tests from UL746C or be molded from a Recognized plastic that has been previously found to comply with the water exposure and immersion tests.
106.4 Enclosed float – operated switches (switch operated by mechanical float) shall be evaluated and marked with an enclosure rating.
108.3 The cord of a float switch shall be evaluated as water resistant, designated as “W” on the outer jacket of the cord, in accordance with UL62, Standard for Flexible Cords.
109.1 Float switches, float-operated switches and pressure switches with a motor rating greater than 2hp at 0-300V or greater than 1hp at 301-600V or containing a mercury switch must be short circuit tested and marked with a short circuit rating.
Section 114 Representative float switches for use in water and/or sewage applications are required to be evaluated to the revised performance requirements in Section 114.
116.1, 116.3 Float switches are not marked with an enclosure rating and are marked for sewage application if applicable.
116.2 Pressure-operated switches shall be marked with the operating pressure rating of the switching contacts and with the maximum rated pressure used as the basis for the pressure test.
Description of Action Required by Manufacturers:
1. Manufacturers of Listed and Recognized float and pressure operated controller products that will require modification of the construction, and/or markings, and those requiring short circuit testing to comply with the new and revised requirements and intending to continue Listing or Recognition after the effective date, are requested to provide a description of the proposed modifications to comply with these requirements to Underwriters Laboratories.
2. Manufacturers having products (described in item 1) that comply with the new and revised requirements without modification or testing and intending to continue Listing or Recognition after the effective date, are requested to provide data demonstrating compliance with these requirements to Underwriters Laboratories.
3. Manufacturers of Listed or Recognized products that are not float or pressure operated controllers are not affected by these requirements and are asked to respond accordingly to Underwriters Laboratories.