Mike Dolt Enterprises
Mike Dolt Enterprises
User: 09387078, Location: Texas
Asked on: Monday, March 28, 2011 at 7:49 pm EDT
Answered on: Tuesday, May 14, 2024 at 3:24 am EDT
Question: I seen a service get turned down by inspector today because a contractor used 3 existing conduits to run 4 sets of 4 parallel conductors .he doubled up on one phase in each conduit and doubled up one phase and neutral on one conduit so all pipes had 5 conductors and one had 6 with the extra neutral.inspector said it was a code violation of 310.4 (B). i looked and everything was right in the pipe concerning 310.4 (B).all conductors are grouped together to prevent induction heating also.i dont see what the problem is .its not the normal thing you see but i dont think its bad .the inspector said if he could prove him wrong he would green tag the service.i know you are going to ask why didnt he run another conduit and i will say you would have to see the job to understand why he could not ,but its not the point the point is 16 in 3.
NEC 310.4(B) Interpretation
NEC 310.4(B) states that "Conductors of different systems, circuits, and voltages shall not be grouped together within the same raceway."The inspector interpreted this rule to mean that only 4 parallel sets of 3 conductors (one phase, one neutral, and one ground) are allowed in a single conduit. He reasoned that doubling up on a phase or neutral conductor violates the rule against grouping conductors of different circuits.
Your Argument
You argue that the conductors are grouped together to prevent induction heating, which is allowed by NEC 310.4(B). You also mention that it is not the normal practice, but you believe it is not a violation.
Inspector's Reasoning
The inspector's reasoning is based on the wording of NEC 310.4(B). The rule specifically prohibits grouping conductors of different systems, circuits, and voltages. The inspector may argue that doubling up on a phase or neutral conductor creates a different circuit because the current flow is now shared between two conductors.
Possible Resolution
To resolve this issue, you could try the following: Provide documentation
Find a technical article or industry standard that supports your interpretation of NEC 310.4(B) and present it to the inspector.
Request an exception
Explain to the inspector the unique circumstances that prevent you from running another conduit and request an exception to the rule.*
Rectify the installation
If possible, separate the conductors into separate conduits to comply with NEC 310.4(B).
Ultimately, the inspector has the final authority. If you cannot convince the inspector, you may have to comply with their request to rectify the installation. However, it is worth discussing your interpretation and providing evidence to support your argument. Flag for review