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Thread: Help with Acceptable Class1 Div 1 material

  1. #11
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    Class 1

    Liquid tight is a class 1 div 2 raceway. I googled this for a paint booth I was doing. Awesome pics and barrier info. I would post but don't want to get in trouble for brands and sites..... was easy to find though!!

  2. #12
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    I had considered adding the following to my first Post (#2) in anticipation of petersonra's (or someone else's) response in Post #4. I thought better of it at the time since the OP is an apprentice and I didn't want to confuse the issue.

    In light of all the further discussion that has arisen, maybe what I should have added:

    "And the convoluted answer for question #1 is there are protection techniques that alter the area classification such as proper ventilation or purged/pressurized systems. In those cases, the area classification would become Class I, Division 2 instead and LFMC is permitted. [Section 501.10(B)(2)(4)] Other protection techniques that permit LFMC in Class I, Division 1 without altering the area classification are Intrinsically Safe Systems [Article 504] and some Combustible Gas Detection Systems [Section 500.7(K)(1) and (3)]. Each of the cases mentioned above require considerable additional maintenance, and alarms. Wiring methods acceptable under Section 501.10(A) are basically passive without the additional bells, whistles and hoops to jump through. NONE of the methods are inexpensive, but the Section 501.10(A) wiring methods are usually the most cost effective - not always, but usually.

    The answer to question #2, assuming no 'convoluted' protection technique, is it is useless to seal an nonexplosionproof enclosure in Division 1 since an interal arc could still occur. However, it wouldn't be necessary to seal an explosionproof conduit body as described in the OP at all. [Section 501.15(A)(1)(2)]"
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

  3. #13
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    Quote Originally Posted by rbalex View Post
    I imagine what you actually received was an explosionproof flexible coupling. [Section 501.10(A)(2)(1)] It is definitely not LFMC. Technically, it isn't even conduit; it is a coupling. The distinction from LFMC is the threads are an integral part of the factory assembly.
    I would agree. The flexible couple that is generally used similar to flexible conduit is unofficially know as horsecock (an old electrician term) but think it is a member of the o cal family. It comes in predetermine lengths. And a seal off must be used between conduit and hose. A tip to remember though is you must install this first before running conduit because the conduit has to be in a precise place because hose can't be altered nor can a union be used except one approved for class 1 division 1 and is installed only between fitting like a ninety or straight approved for horsecock couplings attached to equipment which I think has a yellow plastic piece instead of green for rigid blue for aluminum, and between the hose. No union can be used on rigid in between seals except after drains on a pressurized and purge system. It requires extra money and thinking evolve but it is required in the place of where you would normally place fmc like by a motor for maintenance purposes. Research Crouse hinge pdfs on hazard locations. It is much easier to interpret than the NEC when it come to what you can and can not use in locations for each type of raceway. Like a common mistake I see a lot is journeyman using form 7 fitting in class 1 division 1 location in between seals or using aluminum with form 9 in class 1 division 2 wet locations. They are not approved for that and it takes years of experience to know what is what and it's exact purpose only found with industrial on the job training. If this is your first time with the class 1 division 1 location just take your time use a pipe wrench not channel locks. Deep thread conduit just a little bit so that division 1 fitting like which is unofficially know as clock boxes will engage at least five threads. And ask an experience electrician how to use gains in order to thread pipe first then bend which is crucial in thread in every rigid conduit as so it fits in thread machine. Because power pony won't deep thread and you will struggle engaging fitting as to not show remaining threads. Good luck and hope I helped and wasn't to off topic.

  4. #14
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    The use of liquid tight flexible conduit use in class 1 division 2 location is a complicated question. It solely depends on the equipment its requirements and if it is a pressurized and purge system that requires hazardous drain or not. For example in a temperature indicator transmitter it is comes with all the seals but no drain but it doesn't require a drain In division 2 location because it is rated at 4 To 20 maps underder 50 volts and the plc panel is vent with hazardous approved low point drains. Here you can use fmc but on a ph indicator transmitter you can not because for one it also must have 120 volts as well as a special factory calibrated cable for controlling and data collection and it doesn't have a drain but does have compression seals. Here you could not because a low point drain is required between compression fitting writhing so many feet and anything in between drain and compression fitting must be treated as Division one. So here you would use explosuonproof union along attached to explosion proof enclosure. The predetermined flexible coupling know as lament terms as horse clock then not necessarily a seal off with hazardous drain but the fitting must be class 1 division 1 approved even though it's in a class2 location and the fitting a known as lament terms clock boxes due to there resemblance to a clock with a hazardous drain and rigid not aluminum re for reducing if needed installation of the drain. A good way to know the exception to where ya can or can't use fmc in class 1 division 2 locations is either contact equipment manufacture or website or get Crouse hinge hazardous locations pdf, a manufacture of fitting for most industrial uses and various conduit bodies used in industrial settings. The info is priceless and is more exact and clear on what exactly is used where than anywhere I have found. Sorry to be so speaking in circles but hazardous location situation are almost always complicated and need a lot of research to what can be used and a very knowledgeable and competent journeyman if not master or super to determine this. Not a helper. If a helper is installing in any hazard location he should humbly request the help and training of an experience journeyman whether he thinks he needs it or not because a mistake can be very costly in these situation where something is installed not up to code fails inspection and has to be cut out damaging seal offs factory cable for insturements as well as costly down time. Plus there are just something that only experience can explain like threading rigid first using gain formula deep threading a little and using a pipe wrench not channel locks that only comes from having been train properly or learned from mistakes. I admire helpers admiration to learn but ya must have experience help and hopefully not in the field not knowing and on here asking questions. If ya that kid like I once was please have a journeyman be with you so that your accountability goes down and ya learn tricks that can't be found in a book. Remember to humbly ask for help and guarantee all journeyman will be more than willing. If ya are with one that isn't informative ask for transfer only if he is not teaching. Not because y'all don't get along. Most helpers don't get along with journeyman only because the forget that no one can offend you or make you angry but your own thoughts. So so off subject good luck.

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