# Grounding Bushings



## qckrun

What code section is grounding bushings located at having a brain fart.

Thanks


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## raider1

Depends on the application.

Here are a couple of code sections to look at,

250.92(B)
250.97

Chris


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## qckrun

Installing a bunch of rigid into a NEMA 1 120/208 panel 3/4"-3". I always get when to use grounding bushings or plastic screw on bushings.


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## Dennis Alwon

qckrun said:


> Installing a bunch of rigid into a NEMA 1 120/208 panel 3/4"-3". I always get when to use grounding bushings or plastic screw on bushings.


Basically if it's a service use the grounding bushings


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## Salvatoreg02

Dennis Alwon said:


> Basically if it's a service use the grounding bushings


Any pipe over 1-1/4 inch and also any wire over #4awg. So if 2# 4 fit in a 1" pipe you need a PB. 
GROUNDING BUSHINGS:
only required when continuity of the equipment ground is broken, then you must use a GB 
EGC can be any metal pipe that is continuous if along that pipe line you enter into a plastic man hole you need to bond all those conduits together!!! Capesci!!


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## K2500

Salvatoreg02 said:


> Any pipe over 1-1/4 inch and also any wire over #4awg. So if 2# 4 fit in a 1" pipe you need a PB.
> GROUNDING BUSHINGS:
> only required when continuity of the equipment ground is broken, then you must use a GB


I was not aware of any requirement to bush based on conduit size alone. Bushings for conduit containing lager than #4 I am aware of.

I have never bushed a conduit simply because it was capable of containing 4 or larger.

Ground bushings or equivalent are also required at services as noted in first reply.


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## raider1

Salvatoreg02 said:


> Any pipe over 1-1/4 inch and also any wire over #4awg. So if 2# 4 fit in a 1" pipe you need a PB.
> GROUNDING BUSHINGS:
> only required when continuity of the equipment ground is broken, then you must use a GB
> EGC can be any metal pipe that is continuous if along that pipe line you enter into a plastic man hole you need to bond all those conduits together!!! Capesci!!


There is no general requirement for pipes over 1 1/4" to have plastic bushings.

Raceways that contain #4 or larger conductors are require to have bushings (300.4(G))

Chris


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## 220/221

qckrun said:


> What code section is grounding bushings located at having a brain fart.
> 
> Thanks


 
The most common two situations where grounding bushings are required are:

1. Concentric KO's where voltage to ground is over 250V

2. Metal pipe containing service conductors




> Basically if it's a service use the grounding bushings


.......on the service conductor riser...... if using locknuts.

The branch circuit/feeder conduit doesn't necessarily require them.


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## RIVETER

Salvatoreg02 said:


> Any pipe over 1-1/4 inch and also any wire over #4awg. So if 2# 4 fit in a 1" pipe you need a PB.
> GROUNDING BUSHINGS:
> only required when continuity of the equipment ground is broken, then you must use a GB
> EGC can be any metal pipe that is continuous if along that pipe line you enter into a plastic man hole you need to bond all those conduits together!!! Capesci!!


I suppose the code has it's requirements but the main thing is that you maintain the continuity of the metal system of your electrical installation. If I were to add a conduit to a system and that conduit is less than the largest of the concentric knockouts available, I would use a metal bonding bushing...especially if you are relying on the conduit system for the continuity of the bonding.


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## electronasized

If your adding a conduit to a system its more than likely a branch circuit. If Im understanding what your asking pull an equipt. ground your done. :001_huh:
Use PVC between the meter and the panel and save your bonding bushings for a rainy day.


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## Salvatoreg02

RIVETER said:


> I suppose the code has it's requirements but the main thing is that you maintain the continuity of the metal system of your electrical installation. If I were to add a conduit to a system and that conduit is less than the largest of the concentric knockouts available, I would use a metal bonding bushing...especially if you are relying on the conduit system for the continuity of the bonding.


That is correct! Thank you for reminding me that when using concentric or eccentric ko's you must use a bonding bushing!


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## raider1

Salvatoreg02 said:


> That is correct! Thank you for reminding me that when using concentric or eccentric ko's you must use a bonding bushing!


No you don't.

A bonding bushing is a possible method to maintain electrical continuity but not the only way.

Reducing washers are listed for grounding and bonding above and below 250 volts to ground.The UL Whitebook states:



> Metal reducing washers are considered suitable for grounding for use in circuits over and under 250 Volts and where installed in accordance with the NEC. Reducing washers are intended for use with metal enclosures having a thickness of 0.053 in. for non-service conductors only. Reducing washers may be installed in enclosures provided with concentric or eccentric knockouts, only after all of the concentric and eccentric rings have been removed. However, those enclosures containing concentric and eccentric knockouts that have been listed for bonding purposes may be used with reducing washers without all knockouts being removed.


So I can use reducing washers around concentric and eccentric knockouts without using a bonding bushing.

Bonding bushings are mostly required on the line side of a service in accordance with 250.92(B).

Chris


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## Salvatoreg02

raider1 said:


> No you don't.
> 
> A bonding bushing is a possible method to maintain electrical continuity but not the only way.
> 
> Reducing washers are listed for grounding and bonding above and below 250 volts to ground.The UL Whitebook states:
> 
> So I can use reducing washers around concentric and eccentric knockouts without using a bonding bushing.
> 
> Bonding bushings are mostly required on the line side of a service in accordance with 250.92(B).
> 
> Chris


But thats a exception to the rule: I stated what I stated. Any inspector would fail you if he felt there was poor continuity with the reducing washers.


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## raider1

Salvatoreg02 said:


> But thats a exception to the rule: I stated what I stated.* Any inspector would fail you if he felt there was poor continuity with the reducing washers.*


An inspector can't fail you if you install the reducing washers in accordance with the UL listing requirements which I posted.

You may not like it but reducing washers are listed for grounding when installed as I pointed out in my earlier post.

Chris


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## Salvatoreg02

raider1 said:


> An inspector can't fail you if you install the reducing washers in accordance with the UL listing requirements which I posted.
> 
> You may not like it but reducing washers are listed for grounding when installed as I pointed out in my earlier post.
> 
> Chris


Wow, I can't believe what I just heard!!! AHJ SUPERSEDES THE NEC. You could argue the issue but you would lose. Sorry to tell you this.


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## Salvatoreg02

raider1 said:


> An inspector can't fail you if you install the reducing washers in accordance with the UL listing requirements which I posted.
> 
> You may not like it but reducing washers are listed for grounding when installed as I pointed out in my earlier post.
> 
> Chris


Also, if the inspector told you to install a grounding bushing also, would you do it or tell him the reducing washers is an expectable means.


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## CFL

Salvatoreg02 said:


> Also, if the inspector told you to install a grounding bushing also, would you do it or tell him the reducing washers is an expectable means.


I argue with the inspector every chance I get.


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## raider1

Salvatoreg02 said:


> Wow, I can't believe what I just heard!!! *AHJ SUPERSEDES THE NEC.* You could argue the issue but you would lose. Sorry to tell you this.


That is absolutely not correct. The AHJ does not have the authority to go beyond what the adopted code requires. If an inspector told me that his decisions supersedes the code I would report him to the chief electrical inspector.



Salvatoreg02 said:


> Also, if the inspector told you to install a grounding bushing also, would you do it or tell him the reducing washers is an expectable means.


If an inspector told me that I must use a bonding bushing around reducing washers on a non service set of concentric knockouts I would politely show them the information from the UL Whitebook.

Chris


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## Salvatoreg02

raider1 said:


> That is absolutely not correct. The AHJ does not have the authority to go beyond what the adopted code requires. If an inspector told me that his decisions supersedes the code I would report him to the chief electrical inspector.
> 
> If an inspector told me that I must use a bonding bushing around reducing washers on a non service set of concentric knockouts I would politely show them the information from the UL Whitebook.
> 
> Chris


I agree with what you stated, but, there are some towns and city's that have certain amendments to the code. Although you are correct certain AHJ can supersede the code in any given application. That have that right! You can bring it to to the CEI but he would not undermine the inspector. 
I installed one ground in stead of two did the testing to prove I was under 25 ohms. He still insisted that I use two. I went to the CEI and he stated that the ground " earth " changes drastically and that the test was great that I was under 25 ohms. But, he still wanted me to install the second one!!


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## raider1

Salvatoreg02 said:


> I agree with what you stated, but, there are some towns and city's that have certain amendments to the code.


Correct, and those amendments to the code need to be written and adopted as law.



> Although you are correct certain AHJ can supersede the code in any given application.


No, the AHJ can't supersede the code. That would be unprofessional conduct and in some states is punishable by law.



> That have that right! You can bring it to to the CEI but he would not undermine the inspector.


Again the inspector does not have the right to supersede the code. The Chief Electrical Inspector has the responsibility to overseen the inspectors and to verify that the inspectors are inspecting to the adopted codes. 



> I installed one ground in stead of two did the testing to prove I was under 25 ohms. He still insisted that I use two. I went to the CEI and he stated that the ground " earth " changes drastically and that the test was great that I was under 25 ohms. But, he still wanted me to install the second one!!


The inspector overstepped his authority by insisting that you provide a second ground rod is the first ground rod met the 25 ohm rule. The CEI also overstepped his authority in this situation.

IMHO both the inspector and the Chief should be challenged on this.

Now I know that in the real world there are petty inspectors and Chief inspectors, but the more you let them get away with this kind of abuse of authority the more it will continue to happen.

Chris


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