Bonding a pull box

Ohm2

Ohm2

Member
Location
Washington
Occupation
Electrician
Interesting enough, I’m getting conflicting answers. Do a metal pull box that has PVC conduit entering and exiting need to be bonded? Feeders are passing through.

Since pull boxes do not have electrical connections (unless conductors are spliced or terminated inside), nor is it apart of the grounding system. Wouldn’t this exclude bonding?
 
Edit the above for clarity: since pull boxes that have pvc entering and exiting do not have electrical connections……^
 
CoolWill said:
250.4, 250.96, and 314.4 say yes.
Click to expand...
Hmmmm, feel free to knock me down if I’m wrong but:
NEC 250.4(A)(3) states that metal parts of electrical equipment must be connected to an effective ground-fault current path. However, since PVC is non-metallic, it does not create a conductive path that requires grounding or bonding. The pull box is not carrying current or part of an electrical grounding system. If metallic conduit were used, bonding would be required, but with PVC, it is not necessary.





NEC 250.96 applies only when enclosures are required to be grounded per other NEC rules, such as 250.86 or 250.110. It requires bonding of metal enclosures if they are likely to become energized or if they are part of the grounding system. Since the pull box is simply a pass-through and is not likely to become energized, bonding is not required. Additionally, because PVC conduit is used, the box is not part of a grounding system. Bonding would only be required if metallic conduit (EMT, IMC, RMC) were connected, which is not the case here.





NEC 314.4 states that metal boxes must be grounded if they contain circuits required to be grounded. However, this applies only if the box itself is required to be grounded, which it is not in this situation. If conductors were spliced or terminated inside the box, grounding would be required, but since it is just a pass-through with PVC conduit, that requirement does not apply. If metallic conduit were used, grounding would be required, but PVC is non-metallic and does not require bonding.





Since the box is only a pass-through with PVC conduit entering and exiting, and there are no splices, terminations, or metallic conduits attached, bonding is not required. However, if conductors were spliced or terminated inside, or if a metallic conduit such as EMT, IMC, or RMC were used, bonding would be necessary. The NEC sections referenced, 250.4, 250.96, and 314.4, do not require bonding in this situation……..or am I wrong?
 
I would say 250.4(A) (2), (3), and/or (4) would apply. The pull box is conductive metal, and it is containing conductors, so it needs to be bonded and earthed. Whether the power coming into it is metallic methods or plastic is irrelevant. Many would say any box containing live conductors is likely to become energized at some point via nicked insulation or damage. This last one is harder to pin down and is an inspector judgement call. The odds go up a lot if the conductors are spliced.
 
suemarkp said:
I would say 250.4(A) (2), (3), and/or (4) would apply. The pull box is conductive metal, and it is containing conductors, so it needs to be bonded and earthed. Whether the power coming into it is metallic methods or plastic is irrelevant. Many would say any box containing live conductors is likely to become energized at some point via nicked insulation or damage. This last one is harder to pin down and is an inspector judgement call. The odds go up a lot if the conductors are spliced.
Click to expand...
I guess it’s a matter of interpretation. I’m actually playing devils advocate with myself. My other side says bond the box, while the other me says…..let’s bring the “should we” or “shouldn’t we” to the code body. Normally you get two different sides.
 
Ohm2 said:
I guess it’s a matter of interpretation. I’m actually playing devils advocate with myself. My other side says bond the box, while the other me says…..let’s bring the “should we” or “shouldn’t we” to the code body. Normally you get two different sides.
Click to expand...
I don't see any interpretation here. 250.4(A)(2) and (3) clearly apply. Sure (4) and (5) use the "likely to be energized" phrase so I would say yes that is open to interpretation
 
Has to be bonded IMHO. It's metal and it contains conductors. If a metal raceway contains conductors it has to be bonded, box is no different.

What if you had a panel all piped with PVC would you not bond it.
 
Ohm2 said:
Since pull boxes do not have electrical connections (unless conductors are spliced or terminated inside), nor is it apart of the grounding system. Wouldn’t this exclude bonding?
Click to expand...
The allowance for no bonding when there are no splices refers to boxes bonded through metallic conduit.
 
Ohm2 said:
NEC 250.4(A)(3) states that metal parts of electrical equipment must be connected to an effective ground-fault current path.
Click to expand...

The pull box is metal. It is a part of electrical equipment. This makes it pretty obvious that it must be connected to an effective ground-fault current path IMHO.
 
Ohm2 said:
Hmmmm, feel free to knock me down if I’m wrong but:
NEC 250.4(A)(3) states that metal parts of electrical equipment must be connected to an effective ground-fault current path. However, since PVC is non-metallic, it does not create a conductive path that requires grounding or bonding. The pull box is not carrying current or part of an electrical grounding system. If metallic conduit were used, bonding would be required, but with PVC, it is not necessary.





NEC 250.96 applies only when enclosures are required to be grounded per other NEC rules, such as 250.86 or 250.110. It requires bonding of metal enclosures if they are likely to become energized or if they are part of the grounding system. Since the pull box is simply a pass-through and is not likely to become energized, bonding is not required. Additionally, because PVC conduit is used, the box is not part of a grounding system. Bonding would only be required if metallic conduit (EMT, IMC, RMC) were connected, which is not the case here.





NEC 314.4 states that metal boxes must be grounded if they contain circuits required to be grounded. However, this applies only if the box itself is required to be grounded, which it is not in this situation. If conductors were spliced or terminated inside the box, grounding would be required, but since it is just a pass-through with PVC conduit, that requirement does not apply. If metallic conduit were used, grounding would be required, but PVC is non-metallic and does not require bonding.





Since the box is only a pass-through with PVC conduit entering and exiting, and there are no splices, terminations, or metallic conduits attached, bonding is not required. However, if conductors were spliced or terminated inside, or if a metallic conduit such as EMT, IMC, or RMC were used, bonding would be necessary. The NEC sections referenced, 250.4, 250.96, and 314.4, do not require bonding in this situation……..or am I wrong?
Click to expand...
The raceway being PVC conduit is all the more reason to need to bond the box. With the conduit being nonmetallic, without the box being bonded to the equipment grounding conductor, you would not have an effective ground fault current path from the box back to the panel. If a ground fault were to occur inside the box, it would not facilitate the overcurrent protective device, you would just have an energized box. (Unless the box was mounted to building steel, in which case I could see it tripping at that point. You would still need to bond the box.)
 
Bond the box? OK, HOW? Are you going to rip open a cable assembly, dig out the grounding conductor, break it and make a bond to the box? That seems crazy to me.
 
gadfly56 said:
Bond the box? OK, HOW? Are you going to rip open a cable assembly, dig out the grounding conductor, break it and make a bond to the box? That seems crazy to me.
Click to expand...
Well it's probably not a cable assembly (did I miss that it is?). Even if it is, what's the big deal on cutting the sheath and cutting/splicing /bugging on to/ or whatever the EGC?
 
gadfly56 said:
Bond the box? OK, HOW? Are you going to rip open a cable assembly, dig out the grounding conductor, break it and make a bond to the box? That seems crazy to me.
Click to expand...
Why would someone pass a cable assembly through a box? Cable's normally only go into boxes to terminate on a device, splice or change wiring methods.
 
electrofelon said:
Well it's probably not a cable assembly (did I miss that it is?). Even if it is, what's the big deal on cutting the sheath and cutting/splicing /bugging on to/ or whatever the EGC?
Click to expand...
From the OP:

Interesting enough, I’m getting conflicting answers. Do a metal pull box that has PVC conduit entering and exiting need to be bonded? Feeders are passing through.

Unless the box gets crushed to the point of rupturing the cables and exposing an ungrounded conductor, I'm not seeing how you energize the box. And if you do get to that point, you probably have far more worrisome issues than whether that box is grounded. Like the San Andreas fault shaking loose California into the eastern Pacific worrisome.
 
Last edited:
gadfly56 said:
From the OP:

Interesting enough, I’m getting conflicting answers. Do a metal pull box that has PVC conduit entering and exiting need to be bonded? Feeders are passing through.

Unless the box gets crushed to the point of rupturing the cables and exposing an ungrounded conductor, I'm not seeing how you energize the box. And if you do get to that point, you probably have far more worrisome issues than whether that box is grounded. Like the San Andreas fault shaking loose California into the eastern Pacific worrisome.
Click to expand...
Ok but pulling a cable assembly thru conduit is somewhat rare so I would assume they are individual conductors.

Regarding the box, we do not get to decide How likely or unlikely it is and make a choice about bonding it. Note code sections have been provided that do not use the " likely to become energized" phrase
 
gadfly56 said:
From the OP:

Interesting enough, I’m getting conflicting answers. Do a metal pull box that has PVC conduit entering and exiting need to be bonded? Feeders are passing through.

Unless the box gets crushed to the point of rupturing the cables and exposing an ungrounded conductor, I'm not seeing how you energize the box. And if you do get to that point, you probably have far more worrisome issues than whether that box is grounded. Like the San Andreas fault shaking loose California into the eastern Pacific worrisome.
Click to expand...
Conductors are "just passing through" metal conduit as well. Do you believe it shouldn't be bonded either?
 
electrofelon said:
Ok but pulling a cable assembly thru conduit is somewhat rare so I would assume they are individual conductors.
Click to expand...
I agree. I think its unlikely that feeders using a cable assembly are being pulled through raceway and pull box.

I think Gadfly56 and Jayh1 brain's are on fire alarm and network cables. :)
 
You must log in or register to reply here.
Top