Neutral to case connection only at 1 place?

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cppoly

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Going through some electrical stuff on grounding. Would this be a violation to connect the neutral buss to the casing at both of these locations?

See attached.
 

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cppoly said:
Going through some electrical stuff on grounding. Would this be a violation to connect the neutral buss to the casing at both of these locations?

See attached.
Click to expand...

It would be required because both enclosures are on the line side of the service disconnect. The metal nipple requires only one bonding jumper can be on either side.
 
Although the fused 800 Amp is called out on the diagram as a "Main" disconnect, I submit that because of the Main Bonding Jumper and the presence of the Grounding Electrode System wiring, that the "Main" is mislabeled and is, in fact, the Service Disconnect.

The other "bonding to casing" shown is in the Meter Socket. In the Meter Socket you don't have a "neutral bus", rather you have a "Grounded Service Conductor". In the Meter Socket, the bonding of the Grounded Service Conductor to the enclosure is part of the creation of a low impedance current path that will trip the power utility transformer overcurrent device(s).

In your diagram, there is NO second bonding of the neutral bus to the case.
 
cppoly said:
Going through some electrical stuff on grounding. Would this be a violation to connect the neutral buss to the casing at both of these locations?

See attached.
Click to expand...

No, but you could omit the neutral to enclosure bonding jumper in the meter socket since there is a bonding jumper on both ends of the nipple between the meter and the main disconnect. Or, as an alternative, leave the neutral to enclosure bond in the meter and only bond one end (either end, your choice) of the nipple between enclosures. As shown or these 2 alternates would all comply. Another option would be to simply change the metallic nipple to PVC and just bond the neutral to the meter enclosure (as already shown) and then you would need to bond the nipple at all.
 
K8MHZ said:
Are there meter sockets with a neutral that is not btlted directly to the enclosure (case)? If so, I have never seen one.
Click to expand...
My favorite utility-approved meter socket is made by Milbank Manufacturing. The PoCo covers seven states. Because of PoCo rules, a 200 Amp lever bypass socket is required for all single phase 240/120 Volt services, 200 Amp or smaller. The PoCo also requires a fifth terminal at nine o'clock for a plug on meter movement to access the neutral, even though I, as yet, am still waiting to see that actually used. Been waiting about 20 years.

Any how. The Milbank commodity meter base bonds the neutral to the case with a labeled removable strap. Similarly, the fifth terminal is bonded to the case with a removable strap. So, without the neutral-case strap, the neutral can float. The lugs and bus are not directly bolted to the case.
 
K8MHZ said:
Are there meter sockets with a neutral that is not bolted directly to the enclosure (case)? If so, I have never seen one.
Click to expand...

Of late you can get non-removable/permanently bonded meter cans and also meter cans are available with a removable bonding jumper. This allows one to use the meter socket for uses other than as service metering such as metering a feeder or PV production. As you allude to, there was a time that one could not get a floating neutral meter can.
CT cans are similar in that you can get factory bonded or with a removable MBJ or none at all.
 
al hildenbrand said:
My favorite utility-approved meter socket is made by Milbank Manufacturing. The PoCo covers seven states. Because of PoCo rules, a 200 Amp lever bypass socket is required for all single phase 240/120 Volt services, 200 Amp or smaller. The PoCo also requires a fifth terminal at nine o'clock for a plug on meter movement to access the neutral, even though I, as yet, am still waiting to see that actually used. Been waiting about 20 years.

Any how. The Milbank commodity meter base bonds the neutral to the case with a labeled removable strap. Similarly, the fifth terminal is bonded to the case with a removable strap. So, without the neutral-case strap, the neutral can float. The lugs and bus are not directly bolted to the case.
Click to expand...

Wow. Before I replied, I checked a 200 amp Milbank socket I had from a job that never got done. No bypass and the neutral is bolted to the bracket, no way to isolate it. They have always been that way. Provided by our PoCo.
 
Marky, FYI:

A spec sheet from Milbank is available by clicking here.

eb3e94ab-4804-46ec-acf8-f6deb58a9a65_1000.jpg

And I note, in this picture, the fifth terminal is lug connected. The latest one I installed I had to remove the guts as part of the existing service alteration, and I recall that the terminal was on a long strap down to the case.
 
K8MHZ said:
Are there meter sockets with a neutral that is not bolted directly to the enclosure (case)? If so, I have never seen one.
Click to expand...
Sure there are. We have to install metering for our PV systems in a couple of jurisdictions, and the neutral cannot be grounded in the cans.
 
Also for "meter centers" there isn't a bond at each unit, but may be bonding jumper that is able to be installed/removed according to needs in the "mains" section.
 
Does section 250.142 Use of Grounded Circuit Conductor for Grounding Equipment, allow the of use of multiple neutral to case connections anywhere on the supply side of service equipment? And is there a limitation to the number of connections?
 
ggunn said:
Sure there are. We have to install metering for our PV systems in a couple of jurisdictions, and the neutral cannot be grounded in the cans.
Click to expand...

kwired said:
Also for "meter centers" there isn't a bond at each unit, but may be bonding jumper that is able to be installed/removed according to needs in the "mains" section.
Click to expand...

Thanks. I guess I need to get out more....
 
cppoly said:
Does section 250.142 Use of Grounded Circuit Conductor for Grounding Equipment, allow the of use of multiple neutral to case connections anywhere on the supply side of service equipment? And is there a limitation to the number of connections?
Click to expand...
Specifically, 2014 NEC 250.142(A) is telling you that the "non-current-carrying metal parts of equipment, raceways and other enclosures" are not restricted to being bonded to the Equipment Grounding Conductor only.

In this thread, you are looking at the LINE side of the Service Disconnecting Means where neither the Equipment Grounding Conductor nor the LOAD side neutral exist. There is only the "Grounded Service Conductor" . . . which the CMP are using the term "Grounded Circuit Conductor" to name, as they (the CMP) are also naming a few other situations ( 2014 NEC 250.142(A)(2) & (3) ).

For the purposes of bonding non-current-carrying equipment, the LINE side of the Service Disconnect grounded service conductor can be connected to as needed, and as many times as needed (like a LOAD side EGC).
 
al hildenbrand said:
Specifically, 2014 NEC 250.142(A) is telling you that the "non-current-carrying metal parts of equipment, raceways and other enclosures" are not restricted to being bonded to the Equipment Grounding Conductor only.

In this thread, you are looking at the LINE side of the Service Disconnecting Means where neither the Equipment Grounding Conductor nor the LOAD side neutral exist. There is only the "Grounded Service Conductor" . . . which the CMP are using the term "Grounded Circuit Conductor" to name, as they (the CMP) are also naming a few other situations ( 2014 NEC 250.142(A)(2) & (3) ).

For the purposes of bonding non-current-carrying equipment, the LINE side of the Service Disconnect grounded service conductor can be connected to as needed, and as many times as needed (like a LOAD side EGC).
Click to expand...

Thanks for that explanation!
 
cppoly said:
Thanks for that explanation!
Click to expand...
:cool: You are welcome.

Now. . . that flash of insight will get messed with when you consider the current in the LINE side service conductors, especially the grounded service conductor, will take ALL available paths back to the source, in this thread's case, presumably the PoCo transformer. Which means that the equipment bonded to the grounded service conductor will likely carry current. This creates a mental hall of mirrors, and, at minimum, a near-religious discussion, about "objectionable current", non-current-carrying equipment, etc.

Just sayin'. ;)
 
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