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Thread: How do you know when it is safe to unbond

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    Member Boss Man's Avatar
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    Default How do you know when it is safe to unbond

    I just wanted to throw this out there and get everyone's opinion. How does everyone check or how do you know when you can safely unbond a common ground from the electric service without burning up all of the appliances in the house.

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    Senior Member ProfessionalLocator's Avatar
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    Default Re: How do you know when it is safe to unbond

    Quote Originally Posted by Boss Man View Post
    I just wanted to throw this out there and get everyone's opinion. How does everyone check or how do you know when you can safely unbond a common ground from the electric service without burning up all of the appliances in the house.

    There is outside a ground going to a driven ground rod, never disconnect that from the ground rod. This is back up for the electric utility company ground and if that ground has burned open bad things will happen. For the appliances a neutral shift will occur which will cause the voltage on the two hot legs to shift between them. These two hot legs are 120v to ground and 240 volt measured to each other. The 120v is for the wall outlets and the 240 volt connection is for electric furnace, stove, central AC, etc. So if the grounds are open one side of the service can jump to 240 volts while the other side drops down to zero volts. Seldom as dramatic as that but almost, the 120 volt appliances burn up.

    There is a smaller ground commonly linking the electric, catv, aluminum siding, etc. together. Opening that ground will not burn up appliances but if there is a faulty grounding system you could get a shock yourself.

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    Default Re: How do you know when it is safe to unbond

    Quote Originally Posted by ProfessionalLocator View Post
    There is outside a ground going to a driven ground rod, never disconnect that from the ground rod. This is back up for the electric utility company ground and if that ground has burned open bad things will happen. For the appliances a neutral shift will occur which will cause the voltage on the two hot legs to shift between them. These two hot legs are 120v to ground and 240 volt measured to each other. The 120v is for the wall outlets and the 240 volt connection is for electric furnace, stove, central AC, etc. So if the grounds are open one side of the service can jump to 240 volts while the other side drops down to zero volts. Seldom as dramatic as that but almost, the 120 volt appliances burn up.

    There is a smaller ground commonly linking the electric, catv, aluminum siding, etc. together. Opening that ground will not burn up appliances but if there is a faulty grounding system you could get a shock yourself.
    I ran on a damage one time which was an electric service to a house. Contractor next door was digging footers for a new house and cut the neutral on a service. The catv was bonded on the common ground at the house coming off the meter. When that neutral was cut, it burnt the coating off the catv ground, melted the siding on the house, and burnt up the catv drop all the way back to the ped. It also fried all the appliances in the house as well. That contractor did not call for locates either, so he or his insurance had a hefty bill from 2 utility companies and the homeowner.

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    Senior Member USIC1's Avatar
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    Default Re: How do you know when it is safe to unbond

    To briefly answer the question -

    It would only be safe if the meter is de-energized.
    EricB likes this.

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    Default Re: How do you know when it is safe to unbond

    Are you really talking about disconnecting the neutral from the ground rod? Or are you talking about disconnecting the ground for the CATV or phone house box?

    With any answer to the above question, the next question would be why would want and/or need to do that?

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    Default Re: How do you know when it is safe to unbond

    Quote Originally Posted by jayc View Post
    Are you really talking about disconnecting the neutral from the ground rod? Or are you talking about disconnecting the ground for the CATV or phone house box?

    With any answer to the above question, the next question would be why would want and/or need to do that?
    Guess I really didn't understand his question either. If your locating, it is very common to unbond the phone and/or tv from the house ground. No harm in doing that. Just make sure you bond it back when done. Sometimes I have to unhook the tv drop itself from the house (to prevent bleeding off) to run the electric. Pisses people off when their watching their porn, but hey gotta do my job.
    Last edited by superman; December 18th, 2013 at 08:59 PM.
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    Default Re: How do you know when it is safe to unbond

    Quote Originally Posted by superman View Post
    Guess I really didn't understand his question either. If your locating, it is very common to unbond the phone and/or tv from the house ground. No harm in doing that. Just make sure you bond it back when done. Sometimes I have to unhook the tv drop itself from the house (to prevent bleeding off) to run the electric. Pisses people off when their watching their porn, but hey gotta do my job.
    Oh I'd be pissed if you interrupted my porn "watching" too.

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    Default Re: How do you know when it is safe to unbond

    Could it not be that the contractor when he hit the neutral also nicked one or both of the hot leads. I had an emergency where a guy augured for posts for a deck. It had snowed and they never cleared the snow to see the marks I had just put down a a couple days before. I went to mark out the catv drop for the crew coming to do the repair. As I went to remove the ground I got shocked. One of the hot leads and neutral must of been touching and I was getting a hot voltage through the neutral.

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    Default Re: How do you know when it is safe to unbond

    Quote Originally Posted by paintitnow View Post
    Could it not be that the contractor when he hit the neutral also nicked one or both of the hot leads. I had an emergency where a guy augured for posts for a deck. It had snowed and they never cleared the snow to see the marks I had just put down a a couple days before. I went to mark out the catv drop for the crew coming to do the repair. As I went to remove the ground I got shocked. One of the hot leads and neutral must of been touching and I was getting a hot voltage through the neutral.
    I'll bet that didn't feel too good.

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    Default Re: How do you know when it is safe to unbond

    Quote Originally Posted by jayc View Post
    Oh I'd be pissed if you interrupted my porn "watching" too.
    Porn is only watched in short sections anyway. They can catch up real easy.....

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    Senior Member jayc's Avatar
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    Default Re: How do you know when it is safe to unbond

    Quote Originally Posted by EricB View Post
    Porn is only watched in short sections anyway. They can catch up real easy.....
    Yeah, but the mood will be ruined. And then I'm going to have to walk to the door, thing in my hand, going, "Hey buddy, when you going to hook it back up so I can put it back down?" And nobody wants to see that.
    EricB likes this.

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    Default Re: How do you know when it is safe to unbond

    I watched the video "New locating safety video" thread by foefn and it said something to the effect of everyone knows when it is safe to disconnect the bond. I just thought that I would see just what I might be missing. Just saying...

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    Default Re: How do you know when it is safe to unbond

    I went back and watched it again. The wire he unhooked never gets disconnected in my area no matter what. There was some phone and catv bonds on his left side they are the ones that get unhooked. Never disconnect the house ground.

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    Junior Member foefn's Avatar
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    Default Re: How do you know when it is safe to unbond

    Yes, I agree with Orangeboots. I unbonded the phone ground from the electric ground. NEVER unhook the electric ground! It is also a very good idea to make sure that the ground is bonded in the ped BEFORE you unhook the (phone or CATV) ground at the house end. In this area of Wisconsin, the electricians have begun installing grounding strips with screws that the other facilities can hook on to. That makes it easier to undo ground bonds but not necessarily any safer. You can always use a voltage tester to verify there is not voltage on the ground before you disconnect. Professional LED Voltage Alert Induction Test Pen - Blue + White + Grey - Free Shipping - DealExtreme or FILI Pen Style Non Contact AC Electric Voltage Detector Sensor Tester 90V~1000V with Clip: Amazon.com: Industrial & Scientific. Or pick your favorite store. I also use these on electric stubs in newer subdivisions. I have exposed stubs a few times to locate and discovered they had been hooked up in the transformer.

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