*tornadoman
December 14th, 2003, 08:55 AM
#691: Sub-panel neutral Author: tornadoman, Posted: Wed Dec 10, 2003 12:06 pm
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My installation is as follows: Meter base; 200A disconnect with breaker; a 200A main-breaker panel (panel A) in the utility room serving as the main panel; a 100A main-lug panel (panel B) in the bedroom wing serving as a sub-panel.
My question is about the grounded conductor. I know the gounded conductor in panel B (which is fed from panel A), should be isolated from the cabinet and grounding conductor. Since panel A is fed from the 200A disconnect, is it also considered a "sub-panel" and therefore have its grounded conductor isolated from the cabinet even though it is the "main" panel?
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#705: Author: Wgoodrich, Posted: Wed Dec 10, 2003 9:08 pm
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The panel or disconnect cabinet that contains that first main disconnect form with overcurrent device is the main service rated panel or disconnect. This panel the grounded [aka neutral] and grounding [aka equipment ground] must be married together electrically within that main service rated panel or disconnect. This would be the 200 amp disconnect at the meter base being the first main disconnect form.
All other panels [including panel A and panel B would be considered as nonservice rated panels [aka sub panels] Panel B is a slave of panel A and panel A is a slave of main service disconnect mounted outside by meter. Any panel installed after the panel or disconnect containing the first main disconnect form is a sub panel requiring an equipment grounding conductor ran with the feeder and hte neutral bar must be isolated from both the grounidng bar and isolated from the metal box of that subpanel.
The grounding electrode conductor [that conductor from your grounding source] must be installed at or before the main service disconnect [box containing the first main disconnect form and overcurrent device {fuse or breaker}].
Hope this helps
Wg
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#728: Author: tornadoman, Posted: Thu Dec 11, 2003 7:58 am
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I thought that's the way it should be. Thanks for the help!
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My installation is as follows: Meter base; 200A disconnect with breaker; a 200A main-breaker panel (panel A) in the utility room serving as the main panel; a 100A main-lug panel (panel B) in the bedroom wing serving as a sub-panel.
My question is about the grounded conductor. I know the gounded conductor in panel B (which is fed from panel A), should be isolated from the cabinet and grounding conductor. Since panel A is fed from the 200A disconnect, is it also considered a "sub-panel" and therefore have its grounded conductor isolated from the cabinet even though it is the "main" panel?
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#705: Author: Wgoodrich, Posted: Wed Dec 10, 2003 9:08 pm
----
The panel or disconnect cabinet that contains that first main disconnect form with overcurrent device is the main service rated panel or disconnect. This panel the grounded [aka neutral] and grounding [aka equipment ground] must be married together electrically within that main service rated panel or disconnect. This would be the 200 amp disconnect at the meter base being the first main disconnect form.
All other panels [including panel A and panel B would be considered as nonservice rated panels [aka sub panels] Panel B is a slave of panel A and panel A is a slave of main service disconnect mounted outside by meter. Any panel installed after the panel or disconnect containing the first main disconnect form is a sub panel requiring an equipment grounding conductor ran with the feeder and hte neutral bar must be isolated from both the grounidng bar and isolated from the metal box of that subpanel.
The grounding electrode conductor [that conductor from your grounding source] must be installed at or before the main service disconnect [box containing the first main disconnect form and overcurrent device {fuse or breaker}].
Hope this helps
Wg
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#728: Author: tornadoman, Posted: Thu Dec 11, 2003 7:58 am
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I thought that's the way it should be. Thanks for the help!