grounding lug use

[hounddog05]

when is it required to use gnding lugs for bonding. For instance a lot of my work is 24x24 Hoffmann enclosures with 2-3" EMT without KOs. These are usually only used as J-boxes and I find myself wanting to use ground lugs and two hole mechanical lugs through bolted to the enclosure. Is this necessary to do all this bonding or does it depend on size of conduit, grounding electrode size, concentric vs eccentric KOs, etc? Thanks.

 

[don_resqcapt19]

What type of conduit? How is the conduit connected to the enclosure? What is the purpose of the conductors in the conduit?

 

[hounddog05]

the conduit is 2.5" EMT with set screw connectors. the box is for junction only. the conductors are fed from switchgear and are feeding a new dist. panel

 

[hounddog05]

in my original post I said grounding lugs.. I meant to say when is it necessary to use grounding bushings in the jboxes.

 

[electrofelon]

when is it required to use gnding lugs for bonding. For instance a lot of my work is 24x24 Hoffmann enclosures with 2-3" EMT without KOs. These are usually only used as J-boxes and I find myself wanting to use ground lugs and two hole mechanical lugs through bolted to the enclosure. Is this necessary to do all this bonding or does it depend on size of conduit, grounding electrode size, concentric vs eccentric KOs, etc? Thanks.

See 250.148 and 250.92(B) and 250.97

 

[kwired]

the conduit is 2.5" EMT with set screw connectors. the box is for junction only. the conductors are fed from switchgear and are feeding a new dist. panel

Metal raceway, metal box without concentric/eccentric KO - the box is suitable to complete the bonding path between raceways if proper raceway terminations are used.

If you have concentric or eccentric KO's you may need to refer to listing of the enclosure some may be rated for use without additional bonding others are not. Over 250 volts also can kick in rules for additional bonding with concentric eccentric KO's. But you mentioned no KO's and making your own holes - so no additional bonding necessary as long as you made the correct size hole for your raceways.

Add: for raceways containing service conductors you do need more then just standard locknuts to ensure the raceway is bonded to the enclosure.

 

[electrofelon]

I looks like an important factor the OP should note is that if there are splices, and wire EGC's, they need to be bonded to the box.

 

[electricalist]

I looks like an important factor the OP should note is that if there are splices, and wire EGC's, they need to be bonded to the box.

So if he used a wire type egc he will need the 2 hole mech. lugs as he thought to ground the 12x12 with the splices? But if the pipe is the ground then the 12x12 is considered bonded / grounded by connection?

 

[kwired]

So if he used a wire type egc he will need the 2 hole mech. lugs as he thought to ground the 12x12 with the splices? But if the pipe is the ground then the 12x12 is considered bonded / grounded by connection?

code you are looking for is:

250.148 Continuity and Attachment of Equipment Grounding Conductors to Boxes.


Where circuit conductors are spliced within a box, or terminated on equipment within or supported by a box, any equipment grounding conductor(s) associated with those circuit conductors shall be connected within the box or to the box with devices suitable for the use in accordance with 250.148(A) through (E)

If the box (they use that term rather loosely here - it can be pretty much any metallic enclosure be it a box, cabinet or even a conduit body) contains splices or connections to enclosed equipment, then if a wire type EGC is run it must connect to the box (or whatever type of enclosure it is).

So if you just have a pull box with no splices or other connections you can pull any EGC through just like the other conductors, but splice or terminate any conductor in that enclosure and you must also connect the EGC to the enclosure if you run a EGC, if raceway only is the EGC you don't need any bonding jumpers/fittings as long as there are no issues with continuity between raceway, connectors, and the enclosure.

 

[electricalist]

code you are looking for is:



If the box (they use that term rather loosely here - it can be pretty much any metallic enclosure be it a box, cabinet or even a conduit body) contains splices or connections to enclosed equipment, then if a wire type EGC is run it must connect to the box (or whatever type of enclosure it is).

So if you just have a pull box with no splices or other connections you can pull any EGC through just like the other conductors, but splice or terminate any conductor in that enclosure and you must also connect the EGC to the enclosure if you run a EGC, if raceway only is the EGC you don't need any bonding jumpers/fittings as long as there are no issues with continuity between raceway, connectors, and the enclosure.

That's how I thought it was as well. When I read efelons post I was just clarifying if he meant the same thing.
The subject of the topic was bonding but I don't recall the op stating egc wire type or raceway. I assumed raceway type so no need for additional bonding because of splices as long as the already mentioned were followed

 

[electricalist]

Kwired I need you to clarify something. There's a post that is about mc outer jacket acceptable for a ground. If so then how do you get around using the ground that's in the cable assembly? You surely can't 're identify it can u ? Or just leave it unconnected.?the post is corrugated mc

 

[kwired]

Kwired I need you to clarify something. There's a post that is about mc outer jacket acceptable for a ground. If so then how do you get around using the ground that's in the cable assembly? You surely can't 're identify it can u ? Or just leave it unconnected.?the post is corrugated mc

When it comes to the topic of this thread - if pulling through a box or conduit body with no splices or connections to contained devices - you don't have to bond to the enclosure - but that probably doesn't come up too often with MC cable.

Otherwise with smaller multiconductor MC cable the sheath is not the EGC except for fairly recent design types like MC-AP. Those cable types do not contain an internal EGC unless they are a type designated for use in health care areas where the wiring method must qualify as an EGC as well as contain a "wire" EGC.

I guess the question maybe is can you use the cable primarily designed for health care applications without connecting the contained green conductor?

In general my answer is no, but I don't have a code section to fully back that up either. My reasoning is if you pull a green wire through a raceway that otherwise qualifies as an EGC, you still need to use it and bond it to boxes where necessary. Now one can say pulling that green in a raceway is a choice, but I say selecting a cable with the green is a choice as well.

Other exception would be to use the listed cable sheath as the EGC and the contained green conductor for an isolated ground application.

Those cable types that do list the sheath as a grounding means also have the aluminum bonding strip in intimate contact with the sheath - the idea is to bond each turn of the sheath to ensure less resistance - in the unlikely event that no turns were contacting one another and any current in the sheath had to make every loop the sheath material does - that makes a much longer conductor out of the sheath. The bond conductor is not the EGC, the sheath is not the EGC - but together they are the EGC.

 

[electricalist]

I agree with you.
When it was pointed out to me on the post the ground in the cable assemble didn't have to be used. I'm thinking then why is it there. Any way thanks.

 

[kwired]

I agree with you.
When it was pointed out to me on the post the ground in the cable assemble didn't have to be used. I'm thinking then why is it there. Any way thanks.

If it were standard MC (not MC-AP or other equivalent) it has to be used as the sheath is not suitable for use as an EGC. If it is MC-AP then it becomes more questionable.