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    cmhomeinspect's Avatar
    cmhomeinspect Posts: 5, Reputation: 1
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    #1

    Dec 21, 2008, 07:48 AM
    Neutral & equipment ground bonded to panel
    As a home inspector, we must determine if the neutral and equipment-ground terminal bars are bonded to the panel enclosures.
    When inspecting, I look for the green or blue colored screws or a copper bar attaching the neutral or equipment bars to the panel.

    My questions are;

    1) What else should I be looing for if anything?

    2) If the neutral or equipment bars are not bonded to the panel, what can happen?

    3) Where can I find more information on this subject?

    Thanks and regards,

    Mike
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
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    #2

    Dec 21, 2008, 08:08 AM

    What your looking for may not be correct.

    It is correct IF the main panel is the 1st disconnect. It is not true for 4 wire "sub-panels" where neutral and ground are kept separate.

    The general rule is that the bond occur at the first disconnect. This could be outside, so the bond is made there and not in the first panel. In this case, the neutral and ground remain separate.

    It's harder to determine if the service is indeed 200 amp, 150 amp or whatever.

    1)
    Water service bonds.
    Multiple wires connected to breakers without pigtails
    Signs of heat (loose connections)
    Equpotential bonding (particularly pools)

    Newer houses will have the telco, cable and electrical bond at the same place. Just make sure they exist, although not at the same place.

    2)
    This is primarily to protect the house for lightning and to provide a equipotential reference for all devices in the house. It can cause havoc with CATV systems if not bonded. Sensitive electrical appliances can fail. Shock hazzard with plumbing fixtures.

    3) There is a sticky in the beginning of this section on how to read the NEC or NFPA online. Otherwise it will set you back about $90.
    tkrussell's Avatar
    tkrussell Posts: 9,659, Reputation: 725
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    #3

    Dec 21, 2008, 11:34 AM
    Good info Kiss provided, let me add to it,

    A neutral is current carrying, so it must be separated after it leaves a panel out to circuits. They only get connected where the grounding to ground rods, etc. to insure all is at earth potential. The equipment ground is reserved for fault currents.

    There are a great many websites with info and diagrams on neutrals and grounding.

    I would think a course would be more helpful, as this is not a topic for self training.

    Does home inspector training only tell you what defects to look for, but no training in the details of correct and improper?


    Did you know that NFPA 70E and OSHA require proper protective equipment rated in calories be worn each time a panelboard is opened?

    Since your in a business that may have you in front of many panels, you should look for training class covering NFPA 70E. You can check with electrical distributors as a start.

    Just opening will require the basic rated face shield and fire rated clothing. Touching for any reason will require higher rated gear.

    Plain eye protection and regular gloves won't do. And any clothing should be cotton, or fire rated. Popular nylon and synthetic blend fabrics are a hazard, as they melt to skin and keep on burning instead of burning away quickly as cotton.

    Home inspectors really should be careful in panels, esp questionable ones. And who knows?
    tkrussell's Avatar
    tkrussell Posts: 9,659, Reputation: 725
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    #4

    Dec 21, 2008, 02:15 PM
    Um seems I hit a nerve, while your disapproval of my facts is off mark, I still addressed your question, what I thought Kiss missed, and added important information, whether you like it or not.

    And you asked what else to look out for, what better than safety.

    Not only you reads this info.
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
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    #5

    Dec 21, 2008, 05:11 PM

    Tk is on the mark. Although it's not typically an Arc-flash hazzard, you should be careful.

    Read the last two paragraphs here: Keys to Understanding NFPA Standard 70E

    Just like I've never seen a screwdriver and a 12 V auto battery meet each other and I don't want to either. In an extreme case the battery can blow up. In a less than extreme case, the screwdriver can hit and burn you pretty bad. An eye is precious.

    Safety is important and you can minimize it by how you connect and disconnect a battery and what PPE (Personal Protective Equipment) you use.

    You need to be aware of what can happen when the panel cover is removed and be prepared.

    If your doing this for a living, at a minimum you should be wearing safety glasses and appropriate gloves.

    I can't balance tk's response. But the "Disagree" was unwarranted. Extra information needs to be accepted on your part.

    We might just pass over your next question.

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