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In 136 Jan. 2001 article as titled above, Rex Cauldwell states “The neutral wires in a subpanel have to be kept isolated from the ground wires, unlike the main panel where the neutral bus is connected to the ground-wire bus. If neutrals and grounds are intermixed on the subpanel the grounding system ends up in parallel with the neutral system all the way back to the main service panel which means neutral current will be flowing through metal water llines, duckwork, gas lines, the metal skin of the house etc. This situation is dangerous, especially to tradesmen working around and under the house. If the neutral breaks, all its current ends up flowing back to the main panel on the grounding system.”
I was hoping the Feb/Mar issue would address this in letters but it doesn’t. I cannot see how adding a second line to “separate” the ground and neutral in the subpanel would have any real impact on the flow. It simply doesn’t make sense to me, since they still end up at the same place on the main panel. I also don’t see why this set up would mean “neutral current will be flowing through metal water lines” etc.
Am I missing something? I’m putting in the sub panel to help alleviate the mess that has been created by a house that has gone from gas to knob and tube, to fuses to circuit breakers. I have a huge panel completely missused with groundbar space I can’t even see, much less use – so I see much of Mr. Cauldwell’s points, but not this one. I would appreciate any enlightenment before I button this thing up. Thanks.
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In 136 Jan. 2001 article as titled above, Rex Cauldwell states "The neutral wires in a subpanel have to be kept isolated from the ground wires, unlike the main panel where the neutral bus is connected to the ground-wire bus. If neutrals and grounds are intermixed on the subpanel the grounding system ends up in parallel with the neutral system all the way back to the main service panel which means neutral current will be flowing through metal water llines, duckwork, gas lines, the metal skin of the house etc. This situation is dangerous, especially to tradesmen working around and under the house. If the neutral breaks, all its current ends up flowing back to the main panel on the grounding system."
I was hoping the Feb/Mar issue would address this in letters but it doesn't. I cannot see how adding a second line to "separate" the ground and neutral in the subpanel would have any real impact on the flow. It simply doesn't make sense to me, since they still end up at the same place on the main panel. I also don't see why this set up would mean "neutral current will be flowing through metal water lines" etc.
Am I missing something? I'm putting in the sub panel to help alleviate the mess that has been created by a house that has gone from gas to knob and tube, to fuses to circuit breakers. I have a huge panel completely missused with groundbar space I can't even see, much less use - so I see much of Mr. Cauldwell's points, but not this one. I would appreciate any enlightenment before I button this thing up. Thanks.