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Thread: Junction box clearance

  1. #1
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    Junction box clearance

    I know we have working clearances for panel board, MCC.. Working space defined 110.26. ...Likely to require examination, adjustment, servicing, or maintenance while energized...

    He is my question, I have a couple of junction boxes where we have a safety relay and some 120V I/O cables running thru it. The question is do I need 3ft clearance? The reason I ask is we are wanting to put a desk next to the Junction box. The desk can be easily move to accommodate any maintenance needs. I'm struggling with telling them they can't put a desk there? I would appreciate your input on the subject!

  2. #2
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    The boxes need only be accessible IMO. The desk can be moved, so I see no real problem.
    "Electricity is really just organized lightning." George Carlin


    Derek

  3. #3
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    I would say that just by the definition of "Readily Accessible" which includes the words "must be able to reached quickly", the answer is no. A desk is not just a desk and not all desks are the same, some are very heavy therefore difficult to move, and the desk has things on it and some of those things have wiring and that wiring can become an obstruction either by virtue of having to move it around to get to the junction box or by having to get someone's permission to shut down their equipment so that you can do your job.
    Ken
    Electrical Project Coordinator


    "Communication, its a wonderful thing, when it happens."

  4. #4
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    Quote Originally Posted by ken44 View Post
    I would say that just by the definition of "Readily Accessible" which includes the words "must be able to reached quickly", the answer is no. A desk is not just a desk and not all desks are the same, some are very heavy therefore difficult to move, and the desk has things on it and some of those things have wiring and that wiring can become an obstruction either by virtue of having to move it around to get to the junction box or by having to get someone's permission to shut down their equipment so that you can do your job.
    I believe j-boxes have to be "accessible" not "readily accessible" therefore the desk is not an issue. But, I don't know what a safety relay is. Does a safety relay have to be readily accessible?

  5. #5
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    A safety relay in this case is the relay off the Estop Pushbutton, redundant inputs and contacts. It's part to the Jbox, that feed back the control system and hard wired to the starter circuits. The only time the relay would need to be accessed would be for troubleshooting. I don't think that would happen vey often.

    On side note the Jbox will not be blocked by the desk entirely, the Jbox will be installed at approx. 5 ft, a couple feet above the desk top, so they can be accessed. The question was do we need the 3 ft open clearance in front of the Jbox, like we do for a distribution panel?

  6. #6
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    Quote Originally Posted by cornbread View Post
    I know we have working clearances for panel board, MCC.. Working space defined 110.26. ...Likely to require examination, adjustment, servicing, or maintenance while energized...

    He is my question, I have a couple of junction boxes where we have a safety relay and some 120V I/O cables running thru it. The question is do I need 3ft clearance? The reason I ask is we are wanting to put a desk next to the Junction box. The desk can be easily move to accommodate any maintenance needs. I'm struggling with telling them they can't put a desk there? I would appreciate your input on the subject!
    Problem here is NEC is doesn't tell us exactly what is likely to require examination, adjustment, servicing or maintenance while energized, and it is left up to interpretation.

    Many places definitely consider switchboards and panelboards to fall into that classification, but if you have a junction box and want to take voltage or current measurements in it - that sort of fits into that description, yet those area almost never required to comply with 110.26.

  7. #7
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    Quote Originally Posted by kwired View Post
    Problem here is NEC is doesn't tell us exactly what is likely to require examination, adjustment, servicing or maintenance while energized, and it is left up to interpretation.
    NEC never allows you to work on energized parts other than switching operations. Isn't it?

  8. #8
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    Quote Originally Posted by Sahib View Post
    NEC never allows you to work on energized parts other than switching operations. Isn't it?
    The NEC, NFPA 70, does not directly address when one is allowed to work on energized equipment.

    The NEC provides the rules for installing disconnects and such to safely work on equipment, but does not cover the actual use of them by workers.

    NFPA 70E (a different standard/code), OSHA, company policy, and other types of regulation would apply.
    "Electricity is really just organized lightning." George Carlin


    Derek

  9. #9
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    Quote Originally Posted by jumper View Post
    The NEC, NFPA 70, does not directly address when one is allowed to work on energized equipment.

    The NEC provides the rules for installing disconnects and such to safely work on equipment, but does not cover the actual use of them by workers.
    The point, IMHO, is NEC is primarily for protecting the common man from the risks of using electricity and the common man is not supposed to work on electrical systems.

  10. #10
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    You have to remember working clearances were in NEC long before NFPA 70E was widely accepted as the safety standard.

    But even with 70E there are times you do tasks on energized or assumed to be energized equipment. By that I mean testing to assure something is not energized, which is considered a live work task until verification of no voltage is completed.

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