UL 508 Practical Application Guidelines On-Line Service (PAGOS)
The UL 508 Practical Application Guidelines On-Line Service (PAGOS) is
an Internet service which provides a source of reference for understanding
and applying the requirements of the Standard of Safety of Industrial Control
Equipment, UL 508, Seventeenth Edition. These guidelines are not intended
to take the place of the requirements of UL 508, Seventeenth Edition, nor
to establish additional requirements.
Features:
- View PAGs on-line in their entirety
- View and/or Download PAGs in PDF format (must have Adobe Acrobat)
- Search for PAGs by keyword, PAG number, Clause number or Clause heading
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PAG ID # |
Description of issue |
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ID #1 |
What are the UL requirements for protective relays? |
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ID #2 |
What are the UL requirements for line reactors? |
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ID #3 |
Do wire bending space requirements apply to terminals provided for field
supplied equipment grounding conductor? |
|
|
What are the requirements for a transient voltage surge suppressor (TVSS)
or metal oxide varistor (MOV) used in industrial control equipment, and
should it be UL Recognized? |
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ID #5 |
What component(s) are considered suitable to be used as the "transient
suppressive device" required by 34.2 in order to utilize
the reduced spacing requirements in Table 34.2, Spacings for Products with
Known and Controlled Transient Voltages? |
|
ID #6 |
Can any UL Recognized transient voltage surge suppressor (TVSS) be used
to comply with 5.4 of UL 840, Standard for Insulation Coordination for Electrical
Equipment? |
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ID #7 |
How are spacing requirements applied to surface-mounted devices? |
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ID #8 |
How are the spacings evaluated at the uninsulated leads of small printed
wiring board mounted components which are across-the-line or at opposite
polarity on printed wiring boards? |
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ID #9 |
How are spacings evaluated on switching semiconductor devices? |
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ID #10 |
When using Table 34.1, what are the spacings requirements for a rectified
dc voltage? |
|
ID #11 |
Polymeric materials intended for the direct support of live parts which
are deficient in Hot Wire Ignition (HWI) performance can be subjected to
Abnormal Overload Testing per UL 746C, the Standard for Polymeric Materials
- Use in Electrical Equipment Evaluations, to verify suitability in a specific
application. This testing requires samples of the product to be subjected
to a variety of overload conditions which are based on the opening times
of the expected branch-circuit overcurrent protective device. How is the
ampere rating of the overcurrent protection determined for a polymeric part
supporting an uninsulated live part, such as a terminal on a motor controller
(contactor)? |
|
ID #12 |
If the available supply source in my laboratory cannot deliver the required
test currents, is there a way for the test to be performed at a lower current
and the results extrapolated up to the required percentage? |
|
ID #13 |
Table 50.1 of UL 746C specifies time limits for Abnormal Overload Testing
as they relate to percentage overload (110, 135 and 200 percent) and overcurrent
protection. If the protective device rating exceeds the values in the table
(i.e. over 400 A), what time limits are appropriate? |
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ID #14 |
Par. 23.1.2 requires that all internal wiring be rated for the voltage of
the circuit in which it is used. This requirement applies to both ac circuits
and dc circuits. However, Listed conductors and Recognized Appliance Wiring
Material are rated in volts without an indication of whether the voltage
rating is rms, peak or dc. How should wiring be selected to comply with
23.1.2 for dc applications? |
|
ID #15 |
What is the pollution degree inside the dust cover of a relay or other mechanical
switching device? |
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