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Thread: Corridor Emergency Egress Lighting via GTD20

  1. #1
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    Corridor Emergency Egress Lighting via GTD20

    I have a corridor application where emergency egress lighting is required. Is there any code-related reason why I cannot wire all of the lights in the corridor to turn on upon loss of normal power to the space using a 20A generator transfer device? The GTD20 will be located above the lay-in ceiling at one end of the corridor and will be fed by 2 separate circuits from two separate panels, one of the panels being an emergency panel fed via the building ATS and the other a normal power panel.

    The AHJ is rejecting this design, but I think he is confusing the UL 1008 GTD20 with a UL 924 bypass device, in which case he would be correct. Failure of either breaker will not leave the space dark as the GTD20 will switch if the normal power circuit fails. Failure of any lighting element will not leave the space dark as there are 20 separate light fixtures in the corridor wired via the GTD20. The GTD20 will bypass switching upon loss of normal power so switch position will not impact emergency egress lighting upon loss of normal power to the space. The two circuits feeding the GTD20 are in separate conduits coming from separate panels. The AHJ wants multiple circuits run out to the light fixtures, either alternating fixtures or dual switched fixtures or something similar.

    I believe that the two circuits to the GTD20 located in the space meets requirements of NEC 700.17. AHJ disagrees but has indicated he is willing to discuss.

    Before I pursue this I wanted to run it by a few others to get opinions/thoughts.

  2. #2
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    I have done it that way a number of times.

    Here's a link http://www.bodine.com/downloads/spec...c.L4100004.pdf
    Last edited by dkidd; 03-06-17 at 03:15 PM.
    The more they overthink the plumbing, the easier it is to stop up the drain

  3. #3
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    Quote Originally Posted by dkidd View Post
    I have done it that way a number of times.
    Ironically I have also, and with this same AHJ providing plan review.

    I'm hoping he is just confusing UL 924 devices with UL 1008 devices. In the case of a UL 924 device (switch bypass relay) I would agree with him.

  4. #4
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    Quote Originally Posted by birtclp View Post
    I have a corridor application where emergency egress lighting is required. Is there any code-related reason why I cannot wire all of the lights in the corridor to turn on upon loss of normal power to the space using a 20A generator transfer device? The GTD20 will be located above the lay-in ceiling at one end of the corridor and will be fed by 2 separate circuits from two separate panels, one of the panels being an emergency panel fed via the building ATS and the other a normal power panel.

    The AHJ is rejecting this design, but I think he is confusing the UL 1008 GTD20 with a UL 924 bypass device, in which case he would be correct. Failure of either breaker will not leave the space dark as the GTD20 will switch if the normal power circuit fails. Failure of any lighting element will not leave the space dark as there are 20 separate light fixtures in the corridor wired via the GTD20. The GTD20 will bypass switching upon loss of normal power so switch position will not impact emergency egress lighting upon loss of normal power to the space. The two circuits feeding the GTD20 are in separate conduits coming from separate panels. The AHJ wants multiple circuits run out to the light fixtures, either alternating fixtures or dual switched fixtures or something similar.

    I believe that the two circuits to the GTD20 located in the space meets requirements of NEC 700.17. AHJ disagrees but has indicated he is willing to discuss.

    Before I pursue this I wanted to run it by a few others to get opinions/thoughts.
    I think the AHJ is correct. Not all of Bodine's stuff is listed for use in an emergency system. The GTD20 is listed only for Article 702 installations. Their bypass relays are listed as UL 924 but you are not just bypassing a switch in your application. UL 1008 listing does not in itself mean a transfer device is acceptable for use in an emergency system.

  5. #5
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    Quote Originally Posted by texie View Post
    I think the AHJ is correct. Not all of Bodine's stuff is listed for use in an emergency system. The GTD20 is listed only for Article 702 installations. Their bypass relays are listed as UL 924 but you are not just bypassing a switch in your application. UL 1008 listing does not in itself mean a transfer device is acceptable for use in an emergency system.
    and there it is, right on their cut sheet, stating

    The GTD20A has been tested by Underwriters Laboratories in accordance with the standards set forth in UL 1008 for Automatic Transfer Switches for Optional Standby Systems. The GTD20A has also been tested by Underwriters Laboratories in accordance with standards
    set forth in CSA C22.2 No. 178 for Automatic Transfer Switches. The GTD20A is UL Listed for field installation.
    They do push it as being usable for emergency lighting. Irony here is this is not the reason the AHJ is disallowing this, so he may be accidentally right, but right is right. I'm gonna still look further to see if there is another device available via a different mfr. Thankfully there is still time to rework the design.

    Appreciate quick responses so far.

  6. #6
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    Quote Originally Posted by birtclp View Post
    and there it is, right on their cut sheet, stating



    They do push it as being usable for emergency lighting. Irony here is this is not the reason the AHJ is disallowing this, so he may be accidentally right, but right is right. I'm gonna still look further to see if there is another device available via a different mfr. Thankfully there is still time to rework the design.

    Appreciate quick responses so far.
    The allowance for a switch bypass has been in Art 700 for a while now and as you point out requires a listing to UL 924. The transfer device for branch circuits has never been allowed in Art 700 and I think that is why their listing shows only use on 702 systems.
    Of note however is that branch circuit transfer devices are now recognized in the 2017 edition at 700.25. Unless you are on the 2017 edition, I don't think there is a compliant way to transfer a branch circuit.

  7. #7
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    Quote Originally Posted by texie View Post
    The allowance for a switch bypass has been in Art 700 for a while now and as you point out requires a listing to UL 924. The transfer device for branch circuits has never been allowed in Art 700 and I think that is why their listing shows only use on 702 systems.
    Of note however is that branch circuit transfer devices are now recognized in the 2017 edition at 700.25. Unless you are on the 2017 edition, I don't think there is a compliant way to transfer a branch circuit.
    Thanks. In SC we are under 2014 and probably will be until 2019 at the rate we update.

    Hopefully Bodine and others will go through testing, etc. required to get these units classified under 700.25 of 2017 NEC.

  8. #8
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    Guess this is what the listing will be going forward...

    http://productspec.ul.com/details.php?ccn=WPWR

  9. #9
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    ...and I found at least one device from ETC.

    https://www.etcconnect.com/Products/.../Features.aspx

  10. #10
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    Here is the proposal that resulted in 700.25.

    Note that is from ETC.
    Attached Images Attached Images
    The more they overthink the plumbing, the easier it is to stop up the drain

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