Need Grounding Bushing?

[Joe Cool]

Hi all.

I'm running 2" EMT from the outside meter/main breaker

to 200A breaker panel in my basement. Do I need a grounding bushing

on the 2" EMT connector that enters my panel in the basement?

Or can I just use the plastic bushing?

Also, there is an LB outside that connects the meter/main breaker cabinet

to the conduit that enters the house. The LB will be partially covered

by an existing deck on that side of the house.

Is that a code violation?

 

[Joe Cool]

After looking through some other posts here, sounds like I definately
need a grounding bushing for a service and the concentric knockouts that I used.
If I am running EMT all the way, do I still
need to run an equipment grounding conductor with the feeders to the panel?

 

[Smart $]

...
If I am running EMT all the way, do I still
need to run an equipment grounding conductor with the feeders to the panel?

No. The EMT qualifies as the EGC.

...and with the service disconnecting means at the meter the run is not service, so no bonding bushing is required.

 

[infinity]

Since the voltage is less than 250 volts to ground the bonding bushing is not required even if you have concentric or eccentric KO's. These are feeder conductors not SEC's so the rule for service raceways does not apply. Is your LB listed for the size conductors that you're using?

 

[Joe Cool]

Cool!! No grounding bushing and EGC not required.
Thank you so much. Less work for me.

I'll have to check on the LB. It's a 2". I guess I assumed
It was big enough for the conductors since the EMT is
Sized for the conductors.

 

[kwired]

I'll have to check on the LB. It's a 2". I guess I assumed
It was big enough for the conductors since the EMT is
Sized for the conductors.

Not all conduit bodies provide sufficient bending space for larger conductor combinations that otherwise fit in same sized raceways. Not all inspectors pay that close attention to this detail either, is maybe why you don't hear much on the topic, if a particular inspector gets onto something that has been overlooked for a long time and starts enforcing it, word gets around, otherwise people continue to do what they have always done in most cases.

 

[Joe Cool]

Not all conduit bodies provide sufficient bending space for larger conductor combinations that otherwise fit in same sized raceways. Not all inspectors pay that close attention to this detail either, is maybe why you don't hear much on the topic, if a particular inspector gets onto something that has been overlooked for a long time and starts enforcing it, word gets around, otherwise people continue to do what they have always done in most cases.

Thanks much for your help Sir.
I found 314.28(A)(2), which scared me for a bit. (6 times 2" = 12")
Then I read 314.28(A)(3) and was relieved.

The inside of the LB says 70 cu.in. and (3) #2/0 conductors.

I wasn't able to find in the code book how they determined cu.in of a 2/0 conductor for box fill.
314.16(A) only goes up to #6awg.


So I guess if 2/0 copper is still okay for 200A and I don't have to pull a EGC I might be okay??

I only have the 2011 code book.

 

[Joe Cool]

My mistake. Sorry.

Didn't look up wire bending space. If I just measure the opening
of the LB from hole to hole, it's about 7 1/2 inches.
If I use table 3.12.6(B), I guess that's okay.

Seems odd that the new LB I bought is marked 71 cu.in. and (3) # 3/0,

but I found an old LB (made in USA) of the same physical size that is marked 70 cu.in. (3) # 2/0.

 

[qcroanoke]

Thanks much for your help Sir.
I found 314.28(A)(2), which scared me for a bit. (6 times 2" = 12")
Then I read 314.28(A)(3) and was relieved.

The inside of the LB says 70 cu.in. and (3) #2/0 conductors.

I wasn't able to find in the code book how they determined cu.in of a 2/0 conductor for box fill.
314.16(A) only goes up to #6awg.


So I guess if 2/0 copper is still okay for 200A and I don't have to pull a EGC I might be okay??

I only have the 2011 code book.

2/0 is only good for 175 amps on the 75 degree table of 310-15B-16. But you may be able to use 310-15 (B) 7-2. of 2014 NEC. What code year are you under?

 

[Joe Cool]

2/0 is only good for 175 amps on the 75 degree table of 310-15B-16. But you may be able to use 310-15 (B) 7-2. of 2014 NEC. What code year are you under?

Thanks much for reply.

Based on what I was able to find online, Wisconsin is still using 2011 NEC.

If I do need to use 3/0, the new LB, which says (3) 3/0,
should still be okay. Is that correct?

Depending on how I measure the LB, I can have up to an 8.5 inch inside bending space.

 

[infinity]

Thanks much for reply.

Based on what I was able to find online, Wisconsin is still using 2011 NEC.

If I do need to use 3/0, the new LB, which says (3) 3/0,
should still be okay. Is that correct?

Depending on how I measure the LB, I can have up to an 8.5 inch inside bending space.

If it's a standard LB measuring is basically pointless because for a 2" raceway you'll almost never get near the minimum requirement of 12". However as you've mentioned you can use the conductor size and number that's listed within the conduit body. If you have (3)-3/0's and the CB say that (3)-3/0's is the maximum then you're good.

 

[Carultch]

Here's my bonding bushing requirement checklist. Anyone want to add to it?

You need a bonding bushing if:
1. Your raceway contains service conductors.
2. Your raceway contains grounding electrode conductors. In fact, you may need one on both ends, for GEC performance.
3. Your raceway terminates on non-metallic enclosures
4. Your raceway terminates on ring knockouts remaining, and the circuit exceeds 250 V to ground nominal
5. Your raceway does not terminate on an enclosure.

You do not need a bonding bushing if:
1. Your raceway is non-metallic. Duh!
2. The other end of your raceway terminates on another enclosure with proper electrical continuity to the raceway. Except where needed for GEC performance.
3. You use alternative fittings, such as a bonding locknut, a bonding Myers hub, with a screw to connect the EGC. Or other listed bonding fittings.
4. In any of the above examples, a standard plastic bushing is an acceptable alternative

 

[Joe Cool]

Thanks to all.

Will mark thread solved.

The only question I still have is... If the 2" LB is partially cover by the deck on that side of the house,

is that a code violation? I would have to remove one decking board to gain access.

 

[kwired]

My mistake. Sorry.

Didn't look up wire bending space. If I just measure the opening
of the LB from hole to hole, it's about 7 1/2 inches.
If I use table 3.12.6(B), I guess that's okay.

Seems odd that the new LB I bought is marked 71 cu.in. and (3) # 3/0,

but I found an old LB (made in USA) of the same physical size that is marked 70 cu.in. (3) # 2/0.

For conductors larger then 6 AWG, volume of enclosures doesn't matter, distance between raceway entries and wire bending space is what matters.

If you were running smaller conductors and wanted to splice some of them in the conduit body or even install devices in the conduit body (not very common but years ago it was more common), then you need to know the volume of the body.

 

[Smart $]

...

The only question I still have is... If the 2" LB is partially cover by the deck on that side of the house,

is that a code violation? I would have to remove one decking board to gain access.

Yes, a violation under strict interpretation of Code...

314.29 Boxes, Conduit Bodies, and Handhole Enclosures to Be Accessible. Boxes, conduit bodies, and hand-hole enclosures shall be installed so that the wiring contained in them can be rendered accessible without removing any part of the building or structure or, in underground circuits, without excavating sidewalks, paving, earth, or other substance that is to be used to establish the finished grade.
Exception: Listed boxes and handhole enclosures shall be permitted where covered by gravel, light aggregate, or non-cohesive granulated soil if their location is effectively identified and accessible for excavation.

 

[kwired]

Yes, a violation under strict interpretation of Code...

Strict interpretation yes, if one installs a section of the deck that is intended to be easily removable then I would like to think it is still accessible. This is not that hard to achieve with a wood floor deck with exposed fasteners, but with some modern decking systems with concealed fasteners - I'd have to say it is a violation if you don't provide an area that has readily available fasteners to gain access where needed.

 

[Smart $]

Strict interpretation yes, if one installs a section of the deck that is intended to be easily removable then I would like to think it is still accessible. This is not that hard to achieve with a wood floor deck with exposed fasteners, but with some modern decking systems with concealed fasteners - I'd have to say it is a violation if you don't provide an area that has readily available fasteners to gain access where needed.

That'd require AHJ's approval, as it is still removing part of the structure.

Now if that deck board were hinged, that'd be a different matter...