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Thread: Working Space around transformers

  1. #11
    Join Date
    Feb 2003
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    Virginia
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    156

    Re: Working Space around transformers

    Charlie b,
    I agree from the design engineer stand point. But, I have examined transformers while hot.
    That word "Likely" is very open to interpretation.

    [ July 25, 2003, 03:59 PM: Message edited by: dcsva@aol.com ]

  2. #12
    Join Date
    Feb 2003
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    3,172

    Re: Working Space around transformers

    Please give me a valid situation where you must examine a transformer, without shutting it down?

    If it is smoking...Shut it down.

    If it is dancing all over...Shut it down.

    If the paint is turning brown...Shut it down.

    If sparks are flying...Shut it down.

    There is no logical reason to remove the front cover while the power is on.

  3. #13
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    Feb 2003
    Location
    Massachusetts
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    48,965

    Re: Working Space around transformers

    Thermal imaging, my coworkers who do that for the company will shut it down when removing the cover and turn it back on to take readings.

  4. #14
    Join Date
    Feb 2003
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    3,172

    Re: Working Space around transformers

    The key phrase is "likely to require'.

    The word "require" is to demand as necessary.

    Likely to "demand as necessary" working while energized. I don't think so.

  5. #15
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    Feb 2003
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    3,172

    Re: Working Space around transformers

    Thermal imaging does not require physical contact. One foot clearance will permit it to be done.

    Sola transformer company has transformers with only two cover screws, for the purpose of removal in constricted areas.

    [ July 25, 2003, 04:15 PM: Message edited by: bennie ]

  6. #16
    Join Date
    Jun 2003
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    5,627

    Re: Working Space around transformers

    Thanks for all the feedback. I've got enough space, so I'll leave 4' in front of the transformer, and 6" around it.

  7. #17
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    Feb 2003
    Location
    Massachusetts
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    Re: Working Space around transformers

    Sure they can squeeze in there between a live parts and whatever, but why should they have to?

    When in doubt I would talk to the local guy to see what he wants.

    In an electric room we always leave the clearance, but I will be honest that in some ceilings we end up with less space, not logical, just how it goes.

  8. #18
    Join Date
    Feb 2003
    Posts
    3,172

    Re: Working Space around transformers

    A ventilated dry type transformer is cooled by the "chimney effect". The sides and back are completely enclosed. There is no need for side and rear clearance.

    Also many of the new transformers do not require a vibration isolator pad, on the floor. The pads actually make them louder.

  9. #19
    Join Date
    May 2003
    Location
    Leesburg, VA
    Posts
    6,933

    Re: Working Space around transformers

    Iwire:

    One thing that never ceases to amaze me is how little room Architechts/enginers give contractors for electric rooms, both main and distribution electric rooms. I realize the cost constraints; these individuals contend with, but sometime it looks like the 10lbs of stuff in the 5 lb box. Sometimes wonder how the contractor's meet the space requirements of the NEC, much less any future expansion.

    We also do IR scanning and in every quote (for jobs where we pull covers) we have a statement regarding transformer covers, will only be removed these covers if our tech feels it is safe (not the exact wording but you get the idea).
    Brian John
    Leesburg, VA

  10. #20

    Re: Working Space around transformers

    Bennie. I remember a service call several years ago that went like this: 1)Employee reprted being shocked while vacuuming. 2) I arrived onsite and investigated possible causes, I found that the recept. used for vacuuming had a broken faceplate. I turned off the circuit and replaced the receptacle. While changing out the recept. I was jolted pretty good by the neutral wire. This was a pigtailed outlet box so this didn't add up to anything good for me. I opened the electrical panel and took voltage readings, found 120 volts Neutral to ground. Next I opened up the transformer (wile energized), to look at connections there since I found nothing wrong w/ wiring in the panel. I did this in an energized state because this was a large retail store full of customers and to de-energize was not a very good option. In the trans,. I found the bonding jumper from XO to frame of trans. missing. The bldg. steel GEC was connected to the frame of the trans. instead of directly to XO. Now that I'd located the problem and had the needed materials onhand to repair this dangerous situation, I had the manager clear the store (for security purposes they said :~) and shut down the trans and made repairs. The reason the store employee was getting shocked while vacuuming..... turns out she was touching the metal "shelf" standards on exterior walls. These are screwed into the metal framing members which are attached to, you guessed it, building steel.

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