Bonding of Neutral and ground. In remote Installations

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Smart $

Smart $

Esteemed Member
Location
Ohio
iwire said:
In my area that is not the case at all, the meter sockets and CT cabinets that the power company specifies will have the neutral permenantly bonded to the enclsure.

This is allowed by NEC 250.142(B) exception 2.
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I am aware of that exception.. but I'm not going to intentionally steer a tradesperson toward the exception if it can be avoided. Pre-configured CT cabinets are available with an isolated grounded conductor (i.e. specifically for post-disconnect installations). If the POCO is furnishing or specifying the cabinet, it is likely configured with the grounded conductor bonded to the cabinet... simply because most (99%...?) CT cabinet installations are pre-disconnect, and POCO's have a tendancy to not change their ways simply because of NEC requirements. :happyno:

Looking at the latest pdf [ View attachment 8138 ], the 6-space I-LINE MLO load-side of the CT cabinet could be the service disconnect(s). The location of the service disconnect has yet to be established, and I don't want to advise improperly until knowing for certain where the service disconnect is located in the system.
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Smart $ said:
I am aware of that exception.. but I'm not going to intentionally steer a tradesperson toward the exception if it can be avoided. Pre-configured CT cabinets are available with an isolated grounded conductor (i.e. specifically for post-disconnect installations). If the POCO is furnishing or specifying the cabinet, it is likely configured with the grounded conductor bonded to the cabinet... simply because most (99%...?) CT cabinet installations are pre-disconnect, and POCO's have a tendancy to not change their ways simply because of NEC requirements.
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The power companies in my area are not flexible about this. The models they accept are bonded.
 
kwired

kwired

Electron manager
Location
NE Nebraska
Smart $ said:
I am aware of that exception.. but I'm not going to intentionally steer a tradesperson toward the exception if it can be avoided. Pre-configured CT cabinets are available with an isolated grounded conductor (i.e. specifically for post-disconnect installations). If the POCO is furnishing or specifying the cabinet, it is likely configured with the grounded conductor bonded to the cabinet... simply because most (99%...?) CT cabinet installations are pre-disconnect, and POCO's have a tendancy to not change their ways simply because of NEC requirements. :happyno:

Looking at the latest pdf [ View attachment 8138 ], the 6-space I-LINE MLO load-side of the CT cabinet could be the service disconnect(s). The location of the service disconnect has yet to be established, and I don't want to advise improperly until knowing for certain where the service disconnect is located in the system.
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I thought the 1200 amp CB near the right side of drawing was the service disconnect, and the 300 amp switch on the far right supplied another CT meter although it is not adjacent to this other equipment. That remote meter on that circuit surprises me a little that the POCO wouldn't want it right near the other meters. Maybe other unknown on site factors may make a difference on this though.
 
Smart $

Smart $

Esteemed Member
Location
Ohio
kwired said:
I thought the 1200 amp CB near the right side of drawing was the service disconnect, ...
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It is definitely "a" disconnect, but it is possible that it is not "the" service disconnect. This is not your typical installation, so I prefer not to make assumptions.
 
kwired

kwired

Electron manager
Location
NE Nebraska
Smart $ said:
It is definitely "a" disconnect, but it is possible that it is not "the" service disconnect. This is not your typical installation, so I prefer not to make assumptions.
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I understand. POCO's also have a tendency to not want any consumer access to anything on supply side of meter(s) either. Which the 1200 amp switch likely has overcurrent devices the owner needs to be able to access. They generally do accept disconnect that is part of or immediately adjacent to a meter center though. That is why I am a little surprised the 300 A switch doesn't have metering right next to it also. If everything in the drawing were supplied by a feeder and not a service, we very likely would not be talking about POCO at all in this installation.
 
F

Fordean

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
Smart $ said:
It is definitely "a" disconnect, but it is possible that it is not "the" service disconnect. This is not your typical installation, so I prefer not to make assumptions.
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the 1200 amp is the main Disconnect. One Throw shuts down all, But the Disconnect to right. For some reason they tied this in on Top of line Side. When I shut down complex to do tie in. (tap Box) That one suite (cleaners) Remained on. I Guess they trying to use the Six switch rule. 1200 main being one, and Dry cleaners being a second. Mine to left Is tie to Bussing. Which is shut down on 1200 amp main thrown in off position. ( cleaners as stated, Stay on) Dont know why they tied to line side. Ct cabinet for cleaners( dont confuse with my CT. Is 120 feet away. Dont know what bonding is done for that one..

Feel like opening it to peak.
 
Smart $

Smart $

Esteemed Member
Location
Ohio
Fordean said:
the 1200 amp is the main Disconnect. One Throw shuts down all, But the Disconnect to right. For some reason they tied this in on Top of line Side. When I shut down complex to do tie in. (tap Box) That one suite (cleaners) Remained on. I Guess they trying to use the Six switch rule. 1200 main being one, and Dry cleaners being a second. Mine to left Is tie to Bussing. Which is shut down on 1200 amp main thrown in off position. ( cleaners as stated, Stay on) Dont know why they tied to line side. Ct cabinet for cleaners( dont confuse with my CT. Is 120 feet away. Dont know what bonding is done for that one..

Feel like opening it to peak.
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I agree with the 1200A being the MAIN disconnect, and I agree in most cases the breaker is the service disconnect... but simply because it shuts down everything connected to it is not verification it is in fact the NEC-qualifying Service Disconnecting Means. Meter disconnect switches are permitted on the line-side of the service disconnecting means (and meters). Nothing you have stated thus far eliminates a secondary disconnecting means from being an NEC-qualifying service disconnecting means. See 230.82 and (3) therein.

I suppose in the end it doesn't matter as long as the exception noted earlier is the method of compliance. I guess the only point I am emphasizing is: assumptions in this trade can cause injuries up to and including fatalities. Yet this matter is will likely not be one of them. I guess I'll move on... :(
 
kwired

kwired

Electron manager
Location
NE Nebraska
Smart $ said:
I agree with the 1200A being the MAIN disconnect, and I agree in most cases the breaker is the service disconnect... but simply because it shuts down everything connected to it is not verification it is in fact the NEC-qualifying Service Disconnecting Means. Meter disconnect switches are permitted on the line-side of the service disconnecting means (and meters). Nothing you have stated thus far eliminates a secondary disconnecting means from being an NEC-qualifying service disconnecting means. See 230.82 and (3) therein.

I suppose in the end it doesn't matter as long as the exception noted earlier is the method of compliance. I guess the only point I am emphasizing is: assumptions in this trade can cause injuries up to and including fatalities. Yet this matter is will likely not be one of them. I guess I'll move on... :(
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I agree that one shouldn't go by assumptions, but there is a disconnect ahead of the meter disconnects.

If there were not a disconnect ahead of them then the six disconnect rule is in violation.
 
Smart $

Smart $

Esteemed Member
Location
Ohio
kwired said:
I agree that one shouldn't go by assumptions, but there is a disconnect ahead of the meter disconnects.
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Several disconnects. Several meters. Which disconnect is ahead of which meter disconnect.

If there were not a disconnect ahead of them then the six disconnect rule is in violation.
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Say for the sake of discussion the 1200A CB is a "meter disconnect". Where is the six disconnect rule violated? Keep in mind that 230.71 says the six switch rule is for each set of service entrance conductors per 230.40 Exceptions 1, 3, 4, or 5.
 
kwired

kwired

Electron manager
Location
NE Nebraska
Smart $ said:
Several disconnects. Several meters. Which disconnect is ahead of which meter disconnect.


Say for the sake of discussion the 1200A CB is a "meter disconnect". Where is the six disconnect rule violated? Keep in mind that 230.71 says the six switch rule is for each set of service entrance conductors per 230.40 Exceptions 1, 3, 4, or 5.
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I agree. Where are the additional sets of service entrance conductors in this example? Only supply is the lines below the 1200 amp breaker in the drawing, everything else is identified as load conductors. We did not know until OP's last post that the 300 A switch is connected to the line side of the 1200 amp switch, so that information means we now have 2 switches on the service conductors.
 
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