Search:

Type: Posts; User: fifty60

Page 1 of 8 1 2 3 4

Search: Search took 0.02 seconds.

  1. Thread: IR VS SCCR

    by fifty60
    Replies
    3$$
    Views
    708

    Basically I have a customer asking for me to...

    Basically I have a customer asking for me to provide the IR of the machine. I plan on giving them them the IR and the SCCR, but I am not sure exactly how to decide what the "IR" rating of the...
  2. Thread: IR VS SCCR

    by fifty60
    Replies
    3$$
    Views
    708

    Understood, for the most part. What I am...

    Understood, for the most part. What I am referring to is the actual labelling required on an industrial machine. I believe at one time the labeling requirement was just for the IR. Would this be...
  3. Thread: IR VS SCCR

    by fifty60
    Replies
    3$$
    Views
    708

    IR VS SCCR

    Before SCCR was established a few code cycles ago, the requirement for the panel was to be marked with the Interrupt Rating (IR). Was this IR simply the interrupt rating of the main OCPD for the...
  4. Replies
    2$$
    Views
    469

    So does that mean that the exception is totally...

    So does that mean that the exception is totally useless, or that the branches after the feeder, within the equipment, do not need to be considered if the branches are below 60A. I read a Bussman...
  5. Replies
    2$$
    Views
    469

    UL 508A SCCR SB4.2 Exception No. 3

    SB4.2 Exception No. 3 states that "Enclosure air conditionors or multimotor and combination load equipment that is cord and attachment plug conneced OR SUPPLIED FROM A BRANCH CIRCUIT PROTECTED AT 60A...
  6. I reread 409.21 (B) and it is an either/or...

    I reread 409.21 (B) and it is an either/or proposition for the circuit breakers. When I first read it, my brain must have misestimated some of the wording and I thought it was requiring both...
  7. NFPA 70 (2017) 409.21 (C) (INDUSTRIAL CONTROL PANELS)

    409.21 (B) Describes two OCPD's, one located ahead of the industrial control panel, and another single OCPD located within the industrial control panel. Is 409.21(C) talking about the OCPD located...
  8. Replies
    11$$
    Views
    1,159

    Would a 35A UL 489 breaker upstream of the UL508...

    Would a 35A UL 489 breaker upstream of the UL508 breaker make make the UL 508 breaker permissible to be used on a non motor load? In this instance it is a VFD load...
  9. Replies
    11$$
    Views
    3,606

    Sorry, not a very good description on my part. ...

    Sorry, not a very good description on my part. The potential for a hazard only exists during the fill. There is normally not a hazard because the process is sealed. But if there is a leak or...
  10. Replies
    11$$
    Views
    3,606

    I'm thinking more along the lines of a fill...

    I'm thinking more along the lines of a fill process in an adequately ventilated space. The hazard only exists when the fill tool is filling the container. When the process is over, the tool is...
  11. Replies
    1$$
    Views
    1,116

    Gas Dispersion Software

    I have read about references to Gas Dispersion software that can help simulate fugitive emmisions to better understand the exent of a Hazardous Area. Can anyone please recommend a good software that...
  12. Replies
    11$$
    Views
    3,606

    Yes, to allow general purpose equipment into the...

    Yes, to allow general purpose equipment into the area during specific times during the day when the process is not running, and the hazard potential no longer exists..
  13. Replies
    11$$
    Views
    3,606

    Persistence of Hazardous Area Classifications

    Is it possible for a Hazardous Area (C1D2) to only be present for specific times during the day?

    For example, if the potential for leaks only exist during 1 hour during the day, the C1D2 area...
  14. Something seems off about the insulation...

    Something seems off about the insulation requirements you listed for UL...is UL talking about cable insulation while NFPA 70 is talking about the individual conductor thickness? I have found that...
  15. Replies
    11$$
    Views
    1,159

    What do you think about the UL508 breaker on a...

    What do you think about the UL508 breaker on a motor circuit that includes a VFD? The 508 breaker would be the only breaker upstream of the VFD and Motor..
  16. Replies
    11$$
    Views
    1,159

    Would you expect the ul 508 breaker to also be...

    Would you expect the ul 508 breaker to also be either ul 489 or ul 1077?
  17. Replies
    11$$
    Views
    1,159

    Yes that is confusing me as well. I am pulling...

    Yes that is confusing me as well. I am pulling this from Allen Bradleys online SCCR tool, which I believe they have recently revamped. They list their 140M breakers as "UL 508 Manual "Type F"...
  18. Replies
    11$$
    Views
    1,159

    UL489 VS UL508: VFD DRIVEN MOTOR

    I have a VFD powered motor. The contactor I am using to bring 480V power to the line side of the VFD has an SCCR of 5KA, unless used with an approved circuit breaker combination.

    All of the...
  19. Replies
    2$$
    Views
    1,599

    For a button like I believe you would be looking...

    For a button like I believe you would be looking at meeting the requirements of 501.150 contacts related to Signalling....not sure if capacitive buttons would meet that requirement or...
  20. That is interesting. What about the situation...

    That is interesting. What about the situation where the grade level flooring is grated above a pit? Would the hazardous area still potentially exist 3 feet (for example) above the grated grade...
  21. Looking at figure 5.10.4(b), which is a Tank Car...

    Looking at figure 5.10.4(b), which is a Tank Car Loading and Unloading via a Closed Transfer System, material transferred only through a dome, the material being transferred is a flammable liquid. ...
  22. Thank you Rbalex, as always.

    Thank you Rbalex, as always.
  23. NFPA 497----Open Transfer System Vs Closed Transfer System

    I am studying NFPA 497. I am looking at figure 5.10.4(c) and 5.10.4(e). (c) uss the terminology "Unloading via a closed transfer system", and (e) uses the terminology "unloading via an open...
  24. Replies
    2$$
    Views
    312

    Interrupt Rating (IR) vs SCCR

    I understand that SCCR and IR are not the same thing. Fuses and Circuit breakers have IR's, and contactors and other power components have SCCR's. The SCCR of an entire equipment cannot be greater...
  25. Replies
    15$$
    Views
    813

    There are a few loads on the supply, maybe 60W...

    There are a few loads on the supply, maybe 60W worth of electronics. I found the issue. A ground monitoring device is one of the loads, and I believe it is connecting to ground somehow periodically...
Results 1 to 25 of 200
Page 1 of 8 1 2 3 4