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  1. #1
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    Default Mechanical disconnect height question

    Location to equipment is OK, but are there height requirements, max/min ground clearance, for mechanical equipment disconnects?
    Thanks in advance.

    Component: >< 10' feet high.
    60 AMP 240V Non-Fusible metallic disconnect enclosure.
    Single phase A-C.
    Disconnect for HVAC.


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  2. #2
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    Default Re: Mechanical disconnect height question

    I see what looks like the mechanical unit barely visible in the left side of the photo - do you have a photo showing that unit from further away.

    A photo showing where it's at, relative height above ground, what it's under, etc?

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
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  3. #3
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    Default Re: Mechanical disconnect height question

    Of course. Sorry. I was not think, per usual.
    Much thanks, Jerry.


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  4. #4
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    Default Re: Mechanical disconnect height question

    That looks like the outside unit of a mini-split system?

    If so, my first concern would be the installation instructions and the clearances required around it.

    If ... IF ... that is a fused disconnect, then it is also overcurrent protection and that has a height requirement; however, if that is just a service disconnect (to service the unit, and that is within the same area as the ladder would be for the unit when servicing the unit), then it likely does not have a height requirement.

    That looks like a stairway up to that/those balcony areas - is that front or rear access (egress)?

    Jerry Peck
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  5. #5
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    Default Re: Mechanical disconnect height question

    Quote Originally Posted by Jerry Peck View Post
    That looks like the outside unit of a mini-split system?

    If so, my first concern would be the installation instructions and the clearances required around it.

    If ... IF ... that is a fused disconnect, then it is also overcurrent protection and that has a height requirement; however, if that is just a service disconnect (to service the unit, and that is within the same area as the ladder would be for the unit when servicing the unit), then it likely does not have a height requirement.

    That looks like a stairway up to that/those balcony areas - is that front or rear access (egress)?
    Rear egress.
    Steel frame egress/ Molded fiberglass decking.

    Commercial/residential.
    HVAC Mechanical service disconnect. For the ductless mini split.
    Air Conditioning Disconnect, Pullout, Non-Fused, 60 AMP, 2-Pole, 120/240 VAC, Metallic, Galvanized Steel Enclosure, NEMA 3R.

    Clarence? Stove top, kitchen vent. What is the clearance?
    Height restrictions.

    Good clearance to equipment. The AC to the left.

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  6. #6
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    Default Re: Mechanical disconnect height question

    The clearance I am questioning is (could be optical illusion in the photo) between the mini-split an the wall, may also be between the mini-split and roof above, potentially even mini-split to mini-split.

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  7. #7
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    Default Re: Mechanical disconnect height question

    The rule seems general. This is were my confusion exists.
    Sec. 110.26(a)(3)(e) As a general rule, you must maintain a 'minimum headroom clearance of 6 ft from the floor or platform up to any overhead obstruction.'

    2017 NEC: NNT Training. Page 85.
    This would be. 110.26 (E) Dedicated Equipment Space.
    1.8 m (6 ft) above equipment or structural ceiling, whichever is lower.

    This workspace is mandatory and applies to 'service equipment,' mechanical in this case, switchboards, panelboard, and motor control centers.

    What do they mean by whichever is lower. Example please.

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  8. #8
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    Default Re: Mechanical disconnect height question

    Quote Originally Posted by ROBERT YOUNG View Post
    What do they mean by whichever is lower. Example please.
    Which is lower, the roof above, or 6 feet "above the equipment"?

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  9. #9
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    Default Re: Mechanical disconnect height question

    Quote Originally Posted by Jerry Peck View Post
    Which is lower, the roof above, or 6 feet "above the equipment"?
    Man I can concuck some amazing Brain Farts. Sorry. No longer clear as mud.

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  10. #10
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    Default Re: Mechanical disconnect height question

    In the photo, the unit shown on the left edge of the photo, the electrical access appears to be from/through the right side of that unit (just like the electrical access to the right unit appears to be from/through the right side of that unit) ... how much clearance is required for electrical access?

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

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