Mike Dolt Enterprises
Mike Dolt Enterprises
User: Drelectrik, Location: New Jersey
Asked on: Saturday, April 23, 2011 at 11:50 pm EDT
Answered on: Tuesday, May 14, 2024 at 4:34 am EDT
Question: Situation:100 amp feeders has bare neutral and neutrals and grounds are bonded at sub panel. A cold water bond is present which is bonded with fabric sheath bare neutral. My understanding is grounds and neutrals must be isolated at sub panels. In this case is it within code to bond at sub panel?Thanks in advance.
No, it is not within code to bond neutrals and grounds at a subpanel.
NEC Requirements
NEC 250.24(A)(1): "Neutral conductors shall not be connected to the grounding system of the premises." NEC 250.24(A)(5): "Neutral conductors shall not be connected to ground at any point except as specifically permitted elsewhere in this Code." NEC 250.30(A)(1): "The grounding electrode conductor(s) shall be connected to the ground bus or grounding terminal in the panelboard or switchboard."Explanation
In your situation, the cold water bond is connected to the fabric sheath bare neutral, which is a neutral conductor. This violates the NEC requirements that neutrals and grounds must be isolated.When neutrals and grounds are bonded, it can create a path for ground current to flow through the neutral conductor and back to the source. This can cause overheating and damage to equipment and wiring.
Solution
The correct solution is to isolate the neutrals and grounds at the subpanel. This means: Remove the bonding jumper between the neutral bus and the grounding bus. Ensure that there are no other connections between neutrals and grounds. Maintain the grounding electrode conductor connection to the grounding bus.
Note:
In some cases, exceptions may be permitted for bonding neutrals and grounds at certain types of locations or installations. However, these exceptions are typically very specific and must be carefully followed. In most cases, it is not permitted to bond neutrals and grounds at a subpanel. Flag for review