# Bonding Bushing Service entrance pipe



## TAGallagher (Sep 21, 2017)

What is the reason for the requirement to install a bonding bushing on the incoming conduit in our main service panel, from the meter box, and bond this to our grounding electrode.

We don't bond anything inside the meter box itself to our main service panel, is there a good electrical explanation as to why this incoming conduit must have a bonding bushing? Even if its just an 1 1/4 offset nipple? 

Thank you for any responses.


----------



## HackWork (Oct 2, 2009)

TAGallagher said:


> What is the reason for the requirement to install a bonding bushing on the incoming conduit in our main service panel, from the meter box, and bond this to our grounding electrode.
> 
> We don't bond anything inside the meter box itself to our main service panel, is there a good electrical explanation as to why this incoming conduit must have a bonding bushing? Even if its just an 1 1/4 offset nipple?
> 
> Thank you for any responses.


 "_We don't bond anything inside the meter box itself to our main service panel_"

The entire meter pan is bonded via the neutral. The neutral lug is attached directly to the pan without an insulator. 

As far as your main question, the way I understand it they just want to ensure that the service entrance raceway is bonded well, so they require something more than a standard locknut. There are many ways to bond it compliantly, a bonding bushing is just one of them.


----------



## JoeSparky (Mar 25, 2010)

Neutral and ground are the same and bonded together sometimes in multiple spots in the service equipment which is anywhere from the point of attachment to your first overcurrent device. If your neutral was to come loose at any of those points, your metal conduit will act as a neutral. The bonding bushing is so the pipe could potentially carry the neutral for the building without arcing out at the locknuts.


----------



## HackWork (Oct 2, 2009)

JoeSparky said:


> Neutral and ground are the same and bonded together sometimes in multiple spots in the service equipment which is anywhere from the point of attachment to your first overcurrent device. *If your neutral was to come loose at any of those points, your metal conduit will act as a neutral. The bonding bushing is so the pipe could potentially carry the neutral for the building without arcing out at the locknuts.*


 That seems like an odd reason. How would bonding one end of the service entrance raceway help that raceway carry the neutral current?


----------



## TGGT (Oct 28, 2012)

HackWork said:


> That seems like an odd reason. How would bonding one end of the service entrance raceway help that raceway carry the neutral current?


Plus with that logic somebody servicing the equipment could become part of the circuit. Doesn't make sense to me.

Sent from my SM-G930T using Tapatalk


----------



## JoeSparky (Mar 25, 2010)

HackWork said:


> That seems like an odd reason. How would bonding one end of the service entrance raceway help that raceway carry the neutral current?


If the inspector is only requiring one end to be bonded, then yes this is stupid. Both ends are required to be bonded. Usually bushings, but wedges or clamps will work too. 
I personally think it would all be safest if there was only 1 neutral to ground connection per house. The neutral should be isolated and separate ground run to anyplace else in the service where this connection is not made. I don't expect this to ever change, nor do I advicate for it. 

Put a Kenny clamp and a few lever nuts on it and everything will be nice and safe:biggrin:


----------



## HackWork (Oct 2, 2009)

JoeSparky said:


> If the inspector is only requiring one end to be bonded, then yes this is stupid.


 It's not the inspector, it's the NEC that requires only one end of the service entrance raceway to be bonded.

Inspectors can't make things up as they go, are you saying that your jurisdiction has an amendment to the NEC requiring both ends of a service entrance raceway to be bonded?



> Both ends are required to be bonded.


 Please cite this code.


----------



## JoeSparky (Mar 25, 2010)

TAGallagher;5198524Even if its just an 1 1/4 offset nipple? [/QUOTE said:


> Concentric knockout?


----------



## HackWork (Oct 2, 2009)

TAGallagher said:


> Even if its just an 1 1/4 offset nipple?





JoeSparky said:


> Concentric knockout?


For a service entrance raceway it doesn't matter what kind of KO it is, the raceway (including an offset nipple) requires more than a standard locknut to bond it.


----------



## JoeSparky (Mar 25, 2010)

HackWork said:


> It's not the inspector, it's the NEC that requires only one end of the service entrance raceway to be bonded.
> 
> Inspectors can't make things up as they go, are you saying that your jurisdiction has an amendment to the NEC requiring both ends of a service entrance raceway to be bonded?
> 
> Please cite this code.


250.92 (b)


----------



## HackWork (Oct 2, 2009)

JoeSparky said:


> 250.92 (b)


That does not require both ends of the service entrance raceway to be bonded.










BTW, this isn't my opinion of the code. I'm just repeating what I have read dozens of times on Mike Holt's, in his training, code courses, every inspector, etc. etc.


----------



## JoeSparky (Mar 25, 2010)

I hadn't seen Mike Holt's slide. Makes sense. @TAGallagher Slap the bonding bushing on for this job to get your inspection. Next job, use a PVC nipple and skip all this nonsense


----------



## HackWork (Oct 2, 2009)

JoeSparky said:


> I hadn't seen Mike Holt's slide. Makes sense. @TAGallagher Slap the bonding bushing on for this job to get your inspection. *Next job, use a PVC nipple and skip all this nonsense*


Definitely. That's all I use.

For an offset nipple, just use a PVC meter offset with a box adapter glued into the female end.


----------

