Bonding of EMT entering and exiting PVC pull box

[apfl86]

Today an Inspector told me that I need to have a Bonding bushing on both my 1 1/4 EMT coming into and exiting the PVC pull box. Its running from the new DP panel up to the roof for new pumps for the Chillers. Its 408 v 14.6 amps so I ran #10 wire(30amp breaker) with a ground straight through all the way from the panel to the motors disconnect. I have a bonding bushing on my disconnect due to having to use the concentric knockouts. The inspector is well known for being a *****(and made me hang an existing 75kva transformer in an existing electrical room due to 1/4" shy of clearance from the back wall) and before I ask him for the article number I've tried looking through the NEC (2008) and I'm not having any luck. I've went over it with my PM and he agrees with me that its not needed and after going through the code book I'm having no luck. Is it something NEW in the 2011 code book or have I been doing it wrong and getting away with it for years now? Thanks for any and all help.

 

[infinity]

A bonding bushing on each end of the EMT will provide continuity of the metallic raceway. Not much different than a bonding jumper around an expansion fitting.

 

[don_resqcapt19]

Rob,
If the first raceway is bonded at the source and the second at the load, is a bonding jumper between the two raceways required at the junction box?

 

[infinity]

Rob,
If the first raceway is bonded at the source and the second at the load, is a bonding jumper between the two raceways required at the junction box?

Good question, my aforementioned example of expansion fittings are specifically spelled out in 250.98. but metallic raceways aren't as clear. The closest I think that you'll get is 250.96 and whether or not that section is applicable to the OP.

250.96 Bonding Other Enclosures.
(A) General. Metal raceways, cable trays, cable armor,
cable sheath, enclosures, frames, fittings, and other metal
non?current-carrying parts that are to serve as grounding
conductors, with or without the use of supplementary
equipment grounding conductors, shall be bonded where
necessary to ensure electrical continuity and the capacity to
conduct safely any fault current likely to be imposed on
them. Any nonconductive paint, enamel, or similar coating
shall be removed at threads, contact points, and contact
surfaces or be connected by means of fittings designed so
as to make such removal unnecessary.

 

[texie]

Art. 314.3 Exception 1 would apply here. This would require bonding bushings and jumper(s).

 

[apfl86]

A bonding bushing on each end of the EMT will provide continuity of the metallic raceway. Not much different than a bonding jumper around an expansion fitting.

Is there a code article that requires this? And if I'm running my ground straight through and grounding both the disconnect and the equipment, and its bonded at the service, why would I have to worry about the bonding of the raceway? I always thought if I pulled a ground (although I was taught if its in EMT or any type of metal tubing not to run a ground and save the money. I just don't trust the next person behind me to tighten and retighten any/all connections) that I didn't have to bond the raceway since its all technically bonded at the service? If that were the case wouldn't you bond everything? Only thing I could possibly see if the conductors were to short out and possible energize the conduit but its its protected through the ground on each side of the PVC box. I'm just trying to see the real reasoning because its a lot of work to pull everything out and bond it since everything is pulled and landed.

 

[infinity]

Forgot about that one.

 

[apfl86]

Art. 314.3 Exception 1 would apply here. This would require bonding bushings and jumper(s).

So basicly per NEC 314.3 Exception 1 anytime you have a PVC box and your using a metallic raceway it has to be bonded. So even with a grounded conductor which is bonded at the one side of the disconnect and bonded at the panel at the ground bar it still has to have bonding bushings on both ends and a jumper between the twoattached to the grounding conductor.

 

[electrofelon]

Is there a code article that requires this? And if I'm running my ground straight through and grounding both the disconnect and the equipment, and its bonded at the service, why would I have to worry about the bonding of the raceway? I always thought if I pulled a ground (although I was taught if its in EMT or any type of metal tubing not to run a ground and save the money. I just don't trust the next person behind me to tighten and retighten any/all connections) that I didn't have to bond the raceway since its all technically bonded at the service? If that were the case wouldn't you bond everything? Only thing I could possibly see if the conductors were to short out and possible energize the conduit but its its protected through the ground on each side of the PVC box. I'm just trying to see the real reasoning because its a lot of work to pull everything out and bond it since everything is pulled and landed.

You can get bonding bushings that are hinged and can thus be installed after the wire is pulled.

 

[Smart $]

You can get bonding bushings that are hinged and can thus be installed after the wire is pulled.

Clamp type, too.

If RMC or IMC can use bonding/grounding wedges:

http://www.kirbyrisk.com/woeb/datasheets/THOBETC00028_5.pdf

I fail to see why wedges would not also work on EMT.

 

[kwired]

Art. 314.3 Exception 1 would apply here. This would require bonding bushings and jumper(s).

Though I don't really like it, I have to agree that 314.3 and exceptions apply.

Now what if you have a nonmetallic enclosure supplied with a single metallic raceway? I have run into that many times and never used bonding bushings. Sometimes if nothing in the enclosure needs an EGC I may not even pull an EGC. Just did some E-stops for a boiler recently exactly that way. Non metallic E - stop body supplied with EMT, nothing inside to connect an EGC to if I were to pull one so why even pull one? And this was an IEC style body with no extra room whatsoever, if you put a grounding bushing on the raceway fitting you will never assemble the cover with attached switch onto the rest of the box as it will take up too much space.

 

[PetrosA]

Instead of pulling everything apart, couldn't you just use two pipe clamps and a wire and bond around the box like you would with a water meter?

 

[cowboyjwc]

Also as they will tell you in every grounding class, don't get grounding and bonding mixed up, they are not the same thing.

 

[don_resqcapt19]

I am still not convinced that 250.96(A) would require bonding at the box. The bonding at each end would permit the raceway to be an effective fault clearing path.
I don't see the exceptions in 314.3 as requiring the bonding jumper. They just require the means to install a bonding jumper.

 

[Gregg Harris]

I am still not convinced that 250.96(A) would require bonding at the box. The bonding at each end would permit the raceway to be an effective fault clearing path.
I don't see the exceptions in 314.3 as requiring the bonding jumper. They just require the means to install a bonding jumper.

I would agree the EMT is not being used as a redundant EGC
250.96 Bonding Other Enclosures.
(A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non?current-carrying parts that are to serve as equipment grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them. Any nonconductive paint, enamel, or similar coating shall be removed at threads, contact points, and contact surfaces or be connected by means of fittings designed so as to make such removal unnecessary.

 

[shortcircuit2]

Instead of pulling everything apart, couldn't you just use two pipe clamps and a wire and bond around the box like you would with a water meter?

314.3 ex#2 requires the bonding inside the box...

 

[don_resqcapt19]

I would agree the EMT is not being used as a redundant EGC
250.96 Bonding Other Enclosures.
(A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non?current-carrying parts that are to serve as equipment grounding conductors, with or without the use of supplementary equipment grounding conductors, shall be bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them. Any nonconductive paint, enamel, or similar coating shall be removed at threads, contact points, and contact surfaces or be connected by means of fittings designed so as to make such removal unnecessary.

The bonding of the raceway at the raceway ends that are not in the non-metallic box, complies with that rule. It does not require bonding in the box in this example because there is an EGC installed in the raceways and that EGC is bonded to the raceways at the ends that are not in the non-metallic box.

 

[infinity]

The bonding of the raceway at the raceway ends that are not in the non-metallic box, complies with that rule. It does not require bonding in the box in this example because there is an EGC installed in the raceways and that EGC is bonded to the raceways at the ends that are not in the non-metallic box.

I don't where 314.3Ex#1 says that? It says that the bonding means has to be inside of the box. It does not say that it has to be part of the box but it can be. Ex#2 is for threaded entries and it specifies that the bonding means is integral to the box.

314.3 Nonmetallic Boxes. Nonmetallic boxes shall be
permitted only with open wiring on insulators, concealed
knob-and-tube wiring, cabled wiring methods with en-
tirely nonmetallic sheaths, flexible cords, and nonmetal-
lic raceways.
Exception No. 1: Where internal bonding means are pro-
vided between all entries, nonmetallic boxes shall be per-
mitted to be used with metal raceways or metal-armored
cables.
Exception No. 2: Where integral bonding means with a
provision for attaching an equipment bonding jumper in-
side the box are provided between all threaded entries in
nonmetallic boxes listed for the purpose, nonmetallic boxes
shall be permitted to be used with metal raceways or metal-
armored cables.

 

[don_resqcapt19]

I don't where 314.3Ex#1 says that? It says that the bonding means has to be inside of the box. It does not say that it has to be part of the box but it can be. Ex#2 is for threaded entries and it specifies that the bonding means is integral to the box.

I guess I only read EX#2 closely. EX #1 requires the bonding...EX#2 only requires a provision for bonding, not the actual bonding.

So since the general rule is that you can't use the non-metallic box with metallic raceways, you have to use the exception to connect metallic raceways to the non-metallic box, and the provision of Ex#1 says you have to bond.

 

[Wenty4]

Bonding of EMT entering and exiting PVC pull box

I think Texie nailed it on the head with Art. 314.3 Exception #1