non-fused service disconnect, load side neutral size

[xguard]

We have a non-fused service disconnect, from the load side the conductors go to a panel and land on the main circuit breaker. The neutral and ground are bonded in the non-fused service disconnect. Should the neutral that runs from the service disconnect to the panel be sized using 250.66 as a minium? The service entrance conductors are #2 and this neutral from the disconnect to the panel is currently a #10. Should it be sized as a #8 based on 250.66? The neutral load for this installation is very small, only a few amps max for control components.

 

[david]

I still see in old gas stations , non fused disconnect adjacent to a fuse block making up the service disconnect for the building , but those are not the norm.

It is unusual to consider the service disconnect a non-fused disconnect adjacent to a panel with main over current protection.

 

[don_resqcapt19]

We have a non-fused service disconnect, from the load side the conductors go to a panel and land on the main circuit breaker. The neutral and ground are bonded in the non-fused service disconnect. Should the neutral that runs from the service disconnect to the panel be sized using 250.66 as a minium? The service entrance conductors are #2 and this neutral from the disconnect to the panel is currently a #10. Should it be sized as a #8 based on 250.66? The neutral load for this installation is very small, only a few amps max for control components.

Yes, see 250.24(C)(1), but in the 2014 code the Table is 250.104(C)(1) and not Table 250.66 like in the previous codes. Since you have made the neutral to ground bond at the disconnect, you will also need a supply side bonding jumper between the disconnect and the EGC bar in the panel.

 

[xguard]

Yes, see 250.24(C)(1), but in the 2014 code the Table is 250.104(C)(1) and not Table 250.66 like in the previous codes. Since you have made the neutral to ground bond at the disconnect, you will also need a supply side bonding jumper between the disconnect and the EGC bar in the panel.

I'm not following how this applies to the neutral conductor that runs from the disconnect to the panel. Could you elaborate on your explanation?

 

[don_resqcapt19]

I'm not following how this applies to the neutral conductor that runs from the disconnect to the panel. Could you elaborate on your explanation?

I see the conductors between the unfused disconnect and the panel with the service overcurrent protective device as service entrance conductors, so I should have cited 230.42(C).
Note, that I don't have anything to cite that says these conductors are service conductors, but I don't see them as feeder conductors. If they are feeder conductors, there is no way to apply 215.2(A)(2) as that sizing is based on Table 250.122 which requires an up stream OCPD...something we don't have here.

That being said, I could also see sizing the grounded conductor based on the load, but you will need a supply side bonding jumper sized per Table 250.104(C)(1) unless you are using a rigid metallic raceway as the supply side bonding jumper.

This is an interesting installation...if the conductors are not service conductors, even though they are on the line side of the service OCPD, do the service bonding rules apply to the raceway between the disconnect and the panel.

One question. Where is the panel in relation to the unfused disconnect?

 

[electrofelon]

I see the conductors between the unfused disconnect and the panel with the service overcurrent protective device as service entrance conductors, so I should have cited 230.42(C).
Note, that I don't have anything to cite that says these conductors are service conductors, but I don't see them as feeder conductors. If they are feeder conductors, there is no way to apply 215.2(A)(2) as that sizing is based on Table 250.122 which requires an up stream OCPD...something we don't have here.

That being said, I could also see sizing the grounded conductor based on the load, but you will need a supply side bonding jumper sized per Table 250.104(C)(1) unless you are using a rigid metallic raceway as the supply side bonding jumper.

This is an interesting installation...if the conductors are not service conductors, even though they are on the line side of the service OCPD, do the service bonding rules apply to the raceway between the disconnect and the panel.

One question. Where is the panel in relation to the unfused disconnect?

Going off memory here - to tired to double check my theory, but I see the OCPD, as still part of the "service equipment " so they are service conductors and you would bond the neutral in the OCPD enclosure. OR I agree you could do what Don suggested too: run a bonding jumper back to the disconnect. In fact using the bonding jumper would avoid any issues with interpretationa of " objectionable current"

 

[xguard]

I see the conductors between the unfused disconnect and the panel with the service overcurrent protective device as service entrance conductors, so I should have cited 230.42(C).
Note, that I don't have anything to cite that says these conductors are service conductors, but I don't see them as feeder conductors. If they are feeder conductors, there is no way to apply 215.2(A)(2) as that sizing is based on Table 250.122 which requires an up stream OCPD...something we don't have here.

That being said, I could also see sizing the grounded conductor based on the load, but you will need a supply side bonding jumper sized per Table 250.104(C)(1) unless you are using a rigid metallic raceway as the supply side bonding jumper.

This is an interesting installation...if the conductors are not service conductors, even though they are on the line side of the service OCPD, do the service bonding rules apply to the raceway between the disconnect and the panel.

One question. Where is the panel in relation to the unfused disconnect?

The panel is next to the nonfused disconnect. They are both located out side. It is for an outdoor lighting system.

 

[david]

The neutral and ground are bonded in the non-fused service disconnect.

I see the conductors between the unfused disconnect and the panel with the service overcurrent protective device as service entrance conductors, so I should have cited 230.42(C). ......................................................
.....................................................One question. Where is the panel in relation to the unfused disconnect?

230.91 Location.
The service overcurrent device shall be an integral part of the service disconnecting means or shall be located immediately adjacent thereto.

I would agree that the location of the panel with over current would determine how you define what the conductors are between the non fused disconnect and the panel with over current protection.

If the non fused is not adjacent than its hard to give an answer since the non fused shouldn’t be there