200A Service Ground/Bond

[infinity]

So option #1 using #4 in lieu of the #6 would be correct? I'm assuming the ground to the water main would still need to be #4.

Yes, the GEC to the water main would be sized according to 250.66. Take a look at 250.24(A)(1) and see how it corresponds to your GEC connection to the ground bar.

 

[hurk27]

Concentric KO's would mean that you cannot use bonding locknut's to bond service raceways. A bonding jumper would need to be used with a bonding bushing. If you had a KO punched for the size of the raceway then you could use a bonding locknut. 250.92(B)(4).

If you read post 12-14 you would see why I made my post, where did bonding locknut come from , it wasn't in those post?

I took those post to be saying that he didn't need the bonding bushing and jumper with concentric KO's? on service conductors or GEC's, maybe I misunderstood?

 

[infinity]

If you read post 12-14 you would see why I made my post, where did bonding locknut come from , it wasn't in those post?

I took those post to be saying that he didn't need the bonding bushing and jumper with concentric KO's? on service conductors or GEC's, maybe I misunderstood?

Sorry for the confusion, with the multiple changing sketches I'm having trouble following along too. Service raceways require bonding beyond the use of 2 standard locknut's. You can use a boning locknut, a bonding bushing or some other approved methods. A bonding locknut can only be used when the KO is the same size as the conduit therefore a concentric or eccentric KO would require the use of a bonding bushing with a bonding jumper.

 

[roger]

What about 250.92(A) it is the requirements of Bonding of Services, see (3)

and 250.92(B) is Method of Bonding at the Service see the note under (4)

At a few of the Western sectionals I have been to, this question was brought up more then once and both times the CMP's and UL said the concentric KO's were not listed for grounding of raceways protecting service conductors or GEC's, and cited the above code sections each time.

You are correct Wayne but, if we remove all the rings and use reducing washers we do not need the bond bushing.

I know I didn't say that earlier and I should have.

If the enclosures concentric and eccentric knock outs are listed for bonding purposes you wouldn't even need to remove all the rings.

That is from the UL White Book.

2007 White Book OUTLET BUSHINGS AND FITTINGS (QCRV)

Quote:
GROUNDING

Metal reducing washers are considered suitable for grounding for use in circuits over and under 250 V and where installed in accordance with ANSI/NFPA 70, ??National Electrical Code.?? Reducing washers are intended for use with metal enclosures having a minimum 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.

Roger

 

[Dennis Alwon]

So the second sketches would be ok?

Panel inside house supplemental ground running through to the meter can then to exterior ground rods, bonding conduits along the way.

Sorry I missed the 2nd 2 pages..:grin::grin:

 

[Cavie]

Still having a hard time getting my head around this.

Would either of these be correct

Option #1
Meter Can

Panel

or

Option #2
Meter Can

Panel

Option #2 the Panel. You cannot run the EGC from the meter to the panel, you have paralled the neutral. Ground the meter can and stop there.

 

[infinity]

Option #2 the Panel. You cannot run the EGC from the meter to the panel, you have paralled the neutral. Ground the meter can and stop there.

Isn't this one of the times that parallel paths for the neutral current are permitted?

 

[Cavie]

Isn't this one of the times that parallel paths for the neutral current are permitted?

When is paralell paths of a neutral ever permitted thru a meter can? When is paralell wires smaller 1/O ever permitted? When is parallel paths ever permitted using two different size wires?

 

[hurk27]

Isn't this one of the times that parallel paths for the neutral current are permitted?

The only thing that was permitted to parallel the neutral is the service raceway between the meter and panel/service disconnect, because a raceway is not a wire. but because of 250.142 you have never needed a EGC between these two points anyway since the grounded service conductor is allowed to serve this very purpose up to the point of the first means of disconnect. and if we look at 250.92(B)(1) it is one of the permitted ways to bond the equipment enclosures of service conductors, or GEC's 250.92(A)(3)

so since the panel has a MJB, the panel is bonded, since most meter cans neutral lugs are mounted to the can, the meter can is bonded, but the raceway between the meter and panel/disconnect is the only thing left to bond and 250.92(B)(4) clearly states "standard locknut's or bushings shall not be the sole means for the bonding required by this section." we are left with bonding locknut's or grounding bushings, bonding locknut's cant be used across concentric KO's

and since we are only bonding the pipe then it is only required to bond one end.:smile:


Roger did you see in that UL section you quoted where it says "for non-service conductors only" I don't think it applies to the service conductors here?

 

[roger]

Roger did you see in that UL section you quoted where it says "for non-service conductors only" I don't think it applies to the service conductors here?

And the definition of "service conductors" does not include GEC's

Roger