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Thread: Another Emergency Lighting Thread

  1. #11
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    emerg. lights are going to be powered by an emerg. panel circuit. The over-ride relay is only to override the switch position of the emerg. fixtures, that's it. So, they are powered by an emerg. circuit, but the relay has a normal ckt wired to it only to sense loss of normal power.

    So if you've lost power to a certain area of emerg. fixtures you've lost your emergency circuit.

    Am I wrong?

  2. #12
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    Quote Originally Posted by IMFOTP View Post
    Say you're an owner of a building/campus with 500+ emergency fixtures, would you rather have 500+ battery packs to maintain or one genset/transfer switch. The expense of replacing battery packs every, idk, 5years can add up. Secondly, with a genset, you can expect full light output from emergency fixtures (battery packs typically don't run fixtures at full light output), hopefully reducing the sheer number needed.

    Generally speaking, emergency fixtures will have a device that senses the presence of normal power, when the normal power circuit is lost the device bypasses the switch state and says, turn on. If you loose power on any branch circuit feeding lighting, the emergency fixtures in that area would override the switch state and turn on, as they are powered by an emergency circuit. The emergency circuit is fed from a transfer switch (transfer switch is fed by normal power and backed up by genset). Transfer switch tells genset to turn on when normal feed is lost.

    That's a quick and dirty explanation, I'd suggest a google search.
    Having maintained a hotel with that many emergency lights and exit signs, I can say that doing the required monthly checks does not take that long, and if there are failures, they can be replaced for a much lower cost than maintaining an emergency generator. I'll also worked at one such hotel that had an emergency generator versus battery backup lights, that generator was eventually mothballed and battery backup lights installed. a hotel or School maintenance man can easily work on/change an emergency light out with another $15 unit, not so much with a legally required emergency generator.
    Electricians do it until it Hertz!

  3. #13
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    Quote Originally Posted by IMFOTP View Post
    I did read through that, the BCELTS seems like overkill for a single fixture. I'd need one for every instance I have a single fixture in a space as emergency. AHJ is making us use them in toilets/workrooms/clasrooms/offices(its crazy). Maybe I'm wrong, and this is what the industry has been forced to use.

    Just came across the wattstopper ELCU-200, i think that would work and satisfy Art. 700. Its meant for up to 20A but I think use on a single fixture would be ok.
    Not the way I read 2017 NEC. ELCUs are for switch bypass only, and cannot transfer power from normal to emergency.

    If I'm understanding this, the NEC has defacto banned the use of GTDs in spaces where switching of emergency light is desired, at least in the way intended by GTD mfrs and in the way they have been used for past 20 years (which was in accordance with the mfr's instructions).

    If this is correct, it means going forward that a BCELTS-compliant GTD device is required at each light fixture, meaning GTD cost just went from $110 to $300 and installation cost also went up since the BCELTS-compliant GTDs are too large to mount on the light fixture.

    It seems to me that NEC, UL, and GTD mfrs need to get together and develop a cost-effective solution. BCELTS devices are for 20A branch circuits, but the loads for local GTDs are typically small, 3A or less (often much less with LED fixtures). Seems there should be an NEC category for luminaire-specific GTDs & a corresponding UL standard that allows ballast/driver sized GTDs

    The NEC has created a mess and engineers, contractors, and AHJs are confused as heck.

  4. #14
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    Quote Originally Posted by birtclp View Post
    Not the way I read 2017 NEC. ELCUs are for switch bypass only, and cannot transfer power from normal to emergency.
    I think article 700.25 (new in 2017) explicitly allows a device like the Wattstopper ELCU-200 to be used as the method of turning on emergency lights in the event of a loss of normal power.

    Charles E. Beck, P.E., Seattle
    Comments based on 2017 NEC unless otherwise noted.

  5. #15
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    Quote Originally Posted by charlie b View Post
    I think article 700.25 (new in 2017) explicitly allows a device like the Wattstopper ELCU-200 to be used as the method of turning on emergency lights in the event of a loss of normal power.

    Good timing, that's what I'm looking at right now. Trying to see how to make that work with 0-10V dimming in a classroom. Would I need a second ELCU-200 to break 0-10V wiring?

  6. #16
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    Quote Originally Posted by IMFOTP View Post
    AHJ is requiring us to install emergency lighting in a classroom at a school. I'm not sure that the IBC requires it, but I'm not fighting that. The building has a generator. The owner wants to switch the one emergency fixture with the rest of the fixtures in the space (makes sense). Normally I would use a Bodine GTD or similar, but having re-read NEC 700, 700.25 doesn't seem to allow the transfer from normal to emergency power at the fixture. I've also found that the spec sheet for the GTD is a dead link on Bodine's Website (maybe a coincidence). I was told to look at using an IOTA ETS. This device powers the fixture from the emergency circuit and never the normal circuit, and will allow you to bypass the switch input, but it looks like I'll need a separate switch just for this one emergency light.

    How are you guys handling instances where there is just one emergency fixture in a space?

    Sorry for the lengthy post, thanks.
    I am curious what link is broken. first off, they are available as well as devices from most other lighting representatives.

    Second, There are remote GTD's and ones mounted in the fixture. The code for them is different. For the ones installed in the fixture, which 700.24 allows. 700.10(B) (2) covers the wiring requirements.

    The Remote ones aren't transfer switches or don't need to be. The light is always fed from the emergency circuit. They have both switched and unswitched normal power input. When the switch leg is off the light is off. When the normal power leg is off the light is on regardless of the state of the switch leg. It isn't a transfer switch so 700.25 isn't the referenced code.


    I know what I don't know, and I know where to go to find it!

  7. #17
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    Came across this today - http://www.myerspowerproducts.com/li...heet_final.pdf

    Per cut sheet it is a "UL 1008 listed branch circuit emergency lighting transfer switch (BCELTS)". Myers rep will be in our office tomorrow, I'll pick his brain.

  8. #18
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    Quote Originally Posted by birtclp View Post
    Came across this today - http://www.myerspowerproducts.com/li...heet_final.pdf

    Per cut sheet it is a "UL 1008 listed branch circuit emergency lighting transfer switch (BCELTS)". Myers rep will be in our office tomorrow, I'll pick his brain.
    So Myers & LVS both carry this product http://www.lvscontrols.com/assets/ep...Spec_Sheet.pdf which is evidently made by LVS, OEM to Myers. It is UL 1008 listed so can be used like the old GTDs. Bodine, Dual-Lite, & Chloride (and I assume others) have a 20A BCELTS device comparable to the Bodine GTD20A that meet UL 1008 and can also be used as a GTD. These are all rated for 20A and are really overkill for a single fixture, and cost accordingly ($250 to $350 range). None of these are designed to be fixture mounted like traditional GTDs so I'm guessing these will likely be field installed instead of shipped with light fixture. ETC also makes a compliant product, but it is pricier and seems more geared toward high-end dimming market.

    Many manufacturers also have emergency lighting control relays that meet UL 924 (http://www.lvscontrols.com/assets/ep...Spec_Sheet.pdf). With these the light fixture(s) are only fed via an emergency panel since these are not UL listed to transfer power from one source to another. The light fixture is switched or dimmed with the other room lights via the emergency lighting control relay, which also forces the light fixture on upon loss of normal power.

    LVS has a good white paper on the topic - http://www.lvscontrols.com/assets/ep...Whitepaper.pdf

    At the end of the day the era of the GTD located at the light fixture appear to be over, at least until the various manufactures are able to come out with a GTD product that meets UL 1008.

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