# grounding bushings



## keepdry (Jul 24, 2012)

Are grounding bushings required on branch circuitry? All branch wiring is either #10 or #12.
We changed from RIGID to PVC for slab feeds. We then changed from PVC back to rigid and then finally EMT. So the whole job is in metal conduit except for the PVC under the slab. All runs are within the interior of a building. No conduits run outside. 
Do I need grounding bushings at the panel? Grounding pigtails at the first junction boxes?
I know I would need them on a service, but not sure about branch.

Thanks.


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## Cletis (Aug 20, 2010)

*?*

We had to put a bunch on at one job because of rings left around connection. We used these 

http://www.garvinindustries.com/ele...tings/grounding-bushings--split-collar/sgb100

No need for any disconnection


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## Cletis (Aug 20, 2010)

maybe start with 250.3


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## icefalkon (Dec 16, 2007)

Cletis said:


> We had to put a bunch on at one job because of rings left around connection. We used these
> 
> http://www.garvinindustries.com/ele...tings/grounding-bushings--split-collar/sgb100
> 
> No need for any disconnection


Yes those split-ring MIGB's are great. They also aren't cheap. Often a grounding locknut will be sufficient for what the engineers want. Supervision often orders MIGB's (Mallable Iron Grounding Bushings) like they're going out of style not realizing the cost.

To answer your question, it's essentially up to the engineer. If they "require" it for a specific reason, then so be it. If you're talking "in general" it's difficult to say as we don't know the specifics. However, if you're not utilizing the bonding bushing properly...ie: actually running your ground through the lug and landing on a ground bar....why waste the money on it? LOL

I have lost my sh*t on guys for putting in 200 MIGB's on a job where they weren't needed into the crown boxes and panels where we punched our own holes.

However, when doing services...you do have to use MIGB's if you entering through concentric/eccentric knockouts or when reducing washers (donuts) are used. This is often carried over to branch circuits...however it's not always necessary. 

It depends on the job, the engineers, job specs, and what your contractor "bought". If he bought Plans and Specs...then yeah...follow the rules. But I'd still suggest bonding locknuts though.


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## BBQ (Nov 16, 2010)

keepdry said:


> Are grounding bushings required on branch circuitry?


It depends if the voltage to ground is above 250 volts AND if there are concentric KOs AND if the concentric are listed for grounding.






> We changed from RIGID to PVC for slab feeds. We then changed from PVC back to rigid and then finally EMT. So the whole job is in metal conduit except for the PVC under the slab. All runs are within the interior of a building. No conduits run outside.
> 
> Do I need grounding bushings at the panel? Grounding pigtails at the first junction boxes?


You may not need any, or you may need some. As I mentioned above there are lot of things to consider. Please look at 250.97




> *250.97 Bonding for Over 250 Volts.* For circuits of over
> 250 volts to ground, the electrical continuity of metal raceways
> and cables with metal sheaths that contain any conductor
> other than service conductors shall be ensured by
> ...




If your circuits are under 250 volts to ground none will require any extra bonding.


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## Riggss (Jan 24, 2013)

Do i need ground bushings on my Meterstacks? The load for all the units.. Wondering if i can get some input? Would that be considered "service entrance "? Most of the feeds are in MC and 2" Flex ( transfers to EMT ) it's a 120/208


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## BBQ (Nov 16, 2010)

Past the breaker they are feeders not services conductors


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## Riggss (Jan 24, 2013)

BBQ said:


> Past the breaker they are feeders not services conductors


Thank you


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