Grounding EMT

[Jmanb13]

I'm planning to run some surface mounted EMT around my garage to add additional 240v circuits. I know EMT can be used as the grounding path which would save me some fill space inside the conduit.

My question involves grounding the EMT to the panel. Since my panel is flush mounted, my plan was to run a short run of NM-B inside the wall to the ceiling where my first metal junction box is and ground it. From that point on I would run THHN through the conduit to the various places around the garage I would need it. Electrically I know it works, but my question is in regards to NEC code. (2014 where i live)

Is it acceptable to ground EMT to the panel using a ~6 foot run of NM-B or does the EMT have to actually run all the way to the panel?

 

[sberry]

You can ground it with a wire.

 

[teamextreme]

It is acceptable to run NM-b for the run to the first box and ground the box/EMT assembly using a ground screw to the box and the ground wire in the NM-b.

 

[ddawg16]

I know many don't agree.....but.....I personally don't like depending on the EMT as the ground source.

I always run a ground wire. I do ground the EMT...but I don't depend on it as a ground.

It's a personal thing.

 

[Jmanb13]

Awesome! Thanks guys.

 

[Bert_]

I know many don't agree.....but.....I personally don't like depending on the EMT as the ground source.

I always run a ground wire. I do ground the EMT...but I don't depend on it as a ground.

It's a personal thing.

It has been tested that even with both the conduit and a separate grounding wire the conduit will carry the majority of the fault current. I think the number was about 75% of the fault current went through the EMT.

Just something to consider.

 

[ddawg16]

It has been tested that even with both the conduit and a separate grounding wire the conduit will carry the majority of the fault current. I think the number was about 75% of the fault current went through the EMT.

Just something to consider.

I can agree with that....it's a much larger conductor....as long as all the connections are solid.

 

[Stuart in MN]

I can agree with that....it's a much larger conductor....as long as all the connections are solid.

That's always been my concern about using conduit as the ground path - it depends on the installer making sure all the connections are good.

 

[Zeke]

Keep the future in mind. I have older EMT in the garage and my meter is showing a weak ground path. It's been there 40-50 years.

 

[teamextreme]

That's always been my concern about using conduit as the ground path - it depends on the installer making sure all the connections are good.

In this context, you/OP/me are the installer. You must not have much faith in your craftsmanship?

 

[finn]

EMT was the law of the land in metro Chicago when I lived there.

Let’s just say that green sheathed (ground) wire wasn’t a big seller.

 

[Jmanb13]

In this context, you/OP/me are the installer. You must not have much faith in your craftsmanship?

I have paid someone else to do something for me a half dozen times in my life. It has been a train wreck every time and I've had to fix or redo it myself. I care far more about my stuff than anyone else ever will.

 

[Low277]

I can agree with that....it's a much larger conductor....as long as all the connections are solid.

I agree. I have seen the effects of connections that are not tight. I prefer to use a grounding conductor in EMT as well.

 

[ddawg16]

EMT was the law of the land in metro Chicago when I lived there.

Let’s just say that green sheathed (ground) wire wasn’t a big seller.

Thanks to unions...………..

 

[manwithtools]

Thanks to unions...………..

Well, unions are questionable when it comes to ground continuity, I'm not confident in most unions in that regard Now a a coupling, it's much better in regards to continuity (just ask the proper communities), but unfortunately, most unions don't like that

I'm sorry, just trying to add some levity......

 

[bullnerd]

I have an additional question about grounding with EMT.

Should the paint be removed from the panel where the emt connects?

Or/and should I just run a wire to the first box ground screw?

I was planning on running a separate ground, but I'm liking this way better since its all emt and I have pre made pigtails for the grounds.

 

[AffableCurmudgeon]

I know many don't agree.....but.....I personally don't like depending on the EMT as the ground source.

I always run a ground wire. I do ground the EMT...but I don't depend on it as a ground.

It's a personal thing.

Around where I live, we do not have ground wire conductors. We only have EMT as ground.

 

[dscheidt]

I have an additional question about grounding with EMT.

Should the paint be removed from the panel where the emt connects?

Or/and should I just run a wire to the first box ground screw?

I was planning on running a separate ground, but I'm liking this way better since its all emt and I have pre made pigtails for the grounds.

Proper emt to box connectors use a lock nut that will gouge the paint and allow the nut to bite into the box, providing a proper ground, even in the presence of paint. Buy a lock nut wrench, it's worth the money.

 

[alfredeneuman]

Buy a lock nut wrench, it's worth the money.

I've bought 2 of them. The first one broke off before the locknut was tight.
I made the mistake of thinking the first one was a fluke....the 2nd one also broke.
An old screwdriver or a dull cold chisel have served me well.

 

[Bottlecapdigger]

We have all seen loose lock nuts, I'm not up on the Canadian code anymore but I believe here in Canada EMT cant be used as the ground. I would pull a ground wire. Down the road if you want to add circuits use it as a pull wire. BCD.

 

[alfredeneuman]

Keep the future in mind. I have older EMT in the garage and my meter is showing a weak ground path. It's been there 40-50 years.

I was born and raised in Long Beach.
What with the yearly fog, and being able to smell the salt air from 5 miles away from the Ocean, I figure 40-50 years is a pretty good record of longevity.

 

[rjn2649]

I don't know anything else BUT to use the EMT as a ground conductor. Yeah you got to make sure to tighten ALL the connections. This means no beers at break time, watch what your doing. Not that hard really...
AND if it was me (I'm weird) I would run BX with a ground through the wall instead of romex...my thoughts.

 

[alfredeneuman]

BX (AC cable) doesn't have a ground wire.
MC cable does

 

[sberry]

What! No beer breaks?

 

[Bert_]

Sometimes this site really amazes me. Many on here are so particular about tool boxes, fabrication, or garage finishes to the point of obsessing over tiny details that hardly matter.

But now when we talk of running conduit they are worried about loose connections and a sloppy install.

 

[rjn2649]

BX (AC cable) doesn't have a ground wire.
MC cable does

Sorry , me being sloppy when I speak...

 

[Jmanb13]

I'm not worried about loose connections, I have almost all of my conduit installed and I have gone through every connection at least twice now and checked for tightness.

Also if your looking for wrenches, this is what I bought and they work wonderfully. I've cranked pretty hard on them and have had no issue.

https://www.amazon.com/gp/product/B018N80XLQ/?tag=atomicindus08-20

 

[smalltown]

I'm in the I don't trust the EMT for a ground so I run a ground wire.
X2 on the Gardner Bender Locknut Wrenches they are handy.