Raceway used as EGC

[electrofelon]

Does the code ever require different or more stringent bonding when a raceway is used as a EGC as opposed to when the is a wire EGC installed? I say no and have never come across any such wording. I personally may adjust my methods a little but cannot think of any situation in which we are required to do anything different....

 

[LEO2854]

Does the code ever require different or more stringent bonding when a raceway is used as a EGC as opposed to when the is a wire EGC installed? I say no and have never come across any such wording. I personally may adjust my methods a little but cannot think of any situation in which we are required to do anything different....

As long as the piping system is wrench tight your good..:thumbsup:

 

[infinity]

I don't even think that wrench tight is a general requirement.

 

[LEO2854]

I don't even think that wrench tight is a general requirement.

That is just a way to say,all set screws,and locknuts are rock solid tight so the piping system has no loose links.

 

[Smart $]

That is just a way to say,all set screws,and locknuts are rock solid tight so the piping system has no loose links.

Actually there is a requirement to bond around loosely joined raceways :happyyes: so "wrenchtight" is not actually required in Chapters 1 through 4. For example, 250.92(B)(2) says if made up wrenchtight. Yet, wrenchtight is generally easier than installing bonding jumpers. hmy:

A few requirements in the hazardous location articles of Chapter 5 require threaded conduit and fittings to be made wrenchtight.

 

[Dennis Alwon]

Perhaps Leo is saying that as long as you feel comfortable that the install is tight and is a good ground then use it.

 

[mike1061]

Didn't the code used to say something like "threaded fittings shall be made wrench tight"?
I remember seeing that.
Thanks
Mike

 

[Smart $]

Actually there is a requirement to bond around loosely joined raceways :happyyes: so "wrenchtight" is not actually required in Chapters 1 through 4. For example, 250.92(B)(2) says if made up wrenchtight. Yet, wrenchtight is generally easier than installing bonding jumpers. hmy:

A few requirements in the hazardous location articles of Chapter 5 require threaded conduit and fittings to be made wrenchtight.

Didn't the code used to say something like "threaded fittings shall be made wrench tight"?
I remember seeing that.
Thanks
Mike

See above

 

[infinity]

Didn't the code used to say something like "threaded fittings shall be made wrench tight"?
I remember seeing that.
Thanks
Mike

It's not a general NEC requirement for all metal raceways. In fact if you're installing RMC and turning on an elbow chances are pretty good that it won't turn all of the way to the needed position and still be tight. You may need to back off a 1/2 turn just to get the orientation correct.

 

[GoldDigger]

It's not a general NEC requirement for all metal raceways. In fact if you're installing RMC and turning on an elbow chances are pretty good that it won't turn all of the way to the needed position and still be tight. You may need to back off a 1/2 turn just to get the orientation correct.

If you need the RMC to be water tight, then the pipe threads are not guaranteed to be water tight if you back the threads off at all, let alone 1/2 turn.

 

[infinity]

If you need the RMC to be water tight, then the pipe threads are not guaranteed to be water tight if you back the threads off at all, let alone 1/2 turn.

Wrench tight or not I don't see how RMC is ever water tight.

 

[weressl]

Does the code ever require different or more stringent bonding when a raceway is used as a EGC as opposed to when the is a wire EGC installed? I say no and have never come across any such wording. I personally may adjust my methods a little but cannot think of any situation in which we are required to do anything different....

1. The raceway should be listed as EGC. Not all raceways are.
2. The manufacturers installation instructions should be followed, since the UL testing of EGC suitability will make sure that the installation instructions will contain all necessary instructions to comply with the EGC requirements. (Ex. RC conduit of each size have a length and current limitation for EGC.)

 

[mike1061]

It's not a general NEC requirement for all metal raceways. In fact if you're installing RMC and turning on an elbow chances are pretty good that it won't turn all of the way to the needed position and still be tight. You may need to back off a 1/2 turn just to get the orientation correct.

Thanks for both replies.

I thought it was a general requirement, but it wasn't clear in my mind. It was a long time ago I read it. In fact it wasn't until a year or so ago, that I figured out it applied to not only ridged fittings but set screw fittings too. Though I always tighten the death out of them. I can't stand loose anything.
Thanks
Mike

 

[electrofelon]

1. 
   (Ex. RC conduit of each size have a length and current limitation for EGC.)

Oh really? I was not aware of this. What is RC? RMC I assume? IS this a UL or manufacturer spec?

Regarding "wrench tight", doesnt this always apply? I.e. it doesnt say, " when used as an EGC, fittings shall be made wrench tight"?

 

[don_resqcapt19]

It's not a general NEC requirement for all metal raceways. In fact if you're installing RMC and turning on an elbow chances are pretty good that it won't turn all of the way to the needed position and still be tight. You may need to back off a 1/2 turn just to get the orientation correct.

Just another reason why conduit couplings should be tapered thread like plumbing couplings. With tapered thread you can have a tight joint and still be able to position the elbow where it needs to be.

 

[don_resqcapt19]

1. The raceway should be listed as EGC. Not all raceways are.
2. The manufacturers installation instructions should be followed, since the UL testing of EGC suitability will make sure that the installation instructions will contain all necessary instructions to comply with the EGC requirements. (Ex. RC conduit of each size have a length and current limitation for EGC.)

When you look at the software from the Steel Tube Institute, you will find that the metallic raceways are suitable for use as an EGC in longer lengths than an EGC of the wire type that was sized per T250.122.

 

[mike1061]

Just another reason why conduit couplings should be tapered thread like plumbing couplings. With tapered thread you can have a tight joint and still be able to position the elbow where it needs to be.

The way I saw it was, the fittings were tapered. Both plumbing and electrical. Are you saying that plumbing couplers are tapered too? And electrical are not? If that's the case why can't we use plumbing couplers? Because there not UL listed for electrical pipe?
Thanks
Mike

 

[Smart $]

The way I saw it was, the fittings were tapered. Both plumbing and electrical. Are you saying that plumbing couplers are tapered too? And electrical are not? If that's the case why can't we use plumbing couplers? Because there not UL listed for electrical pipe?
Thanks
Mike

Electrical rigid couplings have straight thread. Plumbers call them thread protectors. Plumbing pipe couplings are not UL listed for rigid conduit.

344.6 Listing Requirements. RMC, factory elbows and
couplings, and associated fittings shall be listed.

 

[electrofelon]

When you look at the software from the Steel Tube Institute, you will find that the metallic raceways are suitable for use as an EGC in longer lengths than an EGC of the wire type that was sized per T250.122.

This implies that there is a limit on a 250.122 EGC and/or that it should be upsized after a certain point. Where is this stated other than the generic catch all about having an efffective low impedence fault path (or whatever the actuall wording is - its still raining and the codebook is still out in the truck )

Does anyone know how/why it was decided that female rigid threads would not be tapered?

 

[Smart $]

...

Does anyone know how/why it was decided that female rigid threads would not be tapered?

Don't know why couplings are straight threads, but AFAIK other fittings and equipment entries are NPT.