User: PanelGuy1315, Location: Louisville
Asked on: Tuesday, June 10, 2025 at 4:25 pm EDT
Answered on: Tuesday, June 10, 2025 at 4:29 pm EDT
Question: Hello All,I have a question about the SqD NF style panelboards. We require the breakers that come with the Aux contact built-in but they take up a 4th pole on the board. This means when we install multiple of these breakers next to each other, the phasing will be different. First breaker will be A-B-C, but the second will be B-C-A. Is this common to do?My electrician is trying to space the breakers apart so that each one is A-B-C, but this is wasting some breaker space that we had reserved for future loads.This panelboard is feeding control panels with DC power supplies and field mounted VFDs.
You're correct that adding an auxiliary contact often increases the width of a circuit breaker, typically making it a "4-pole" device even if it's a 3-pole breaker otherwise. And yes, mounting adjacent 3-pole+Aux breakers in an NF panel will result in a phase rotation difference if they are simply installed right next to each other.Here's a breakdown of the situation and what to consider
Understanding the Issue
NF Panelboard Design
NF panelboards are designed for flexibility. Their stab assemblies are designed to accept breakers in any position.
Phase Rotation
While the panelboard doesn't "enforce" a particular phase rotation, it is common to think about the phases being in an A-B-C sequence down the panel. For typical 3-phase loads (like motors), maintaining consistent phase rotation is important.
Auxiliary Contacts
Auxiliary contacts are small switches within the breaker that change state when the breaker trips. They are often used for alarming, monitoring, or control functions. Their presence doesn't directly affect the power flow, but it does affect the physical size of the breaker.
Is Different Phasing Common? No, it's not generally intended, but it's also often acceptable depending on the loads. If you just directly install adjacent breakers, you will end up with differing phasing on each breaker. Important Consideration: Your Loads. This is the critical question. If your DC Power Supplies and VFDs are single-phase: The phase rotation doesn't matter. These devices draw power from two phases (e.g., A-B, B-C, or C-A) or one phase and a neutral. The rotation is irrelevant. If your DC Power Supplies and VFDs are 3-phase: This is where it can become a problem. If you have several of these, it's a very bad idea to feed adjacent 3-phase loads with this out-of-phase installation.
The Correct Approach1. Determine if Phase Rotation Matters
This is the most important step. Are your loads phase-sensitive? Specifically, do you have any 3-phase loads that need consistent phase rotation?2.
If Phase Rotation Doesn't Matter (Single-Phase Loads)
Efficiency is key. Install the breakers side-by-side to maximize the number of breakers that can be installed. Labeling is important. Clearly label each breaker and its corresponding load. Don't assume the next guy will know. Document the "non-standard" installation. Put a note inside the panel explaining the breaker arrangement and why it was done. This will save headaches later.3. If Phase Rotation Does Matter (3-Phase Loads)
Re-evaluate your breaker selection. Is there another breaker with aux contact that is narrower in the panel? It may be worth changing. Consider other Aux contact methods. Can you add a field-mounted aux contact? Option 1 (Your Electrician's Approach - Spacing)
Your electrician is correct that spacing them out achieves consistent phase rotation. However, it sacrifices panel space. This is a valid approach if space is less important than easy maintenance and consistent phase rotation.
Option 2 (Panel Modification)
Potentially move branch breakers around to create a dedicated "3-phase" section and a "single-phase" section, allowing side-by-side breaker installation.4.
Documentation
Regardless of the approach, thoroughly document the panel configuration. A clear one-line diagram and panel schedule are essential.
Recommendations Talk to SqD (Schneider Electric) Technical Support. Explain your situation to them. They may have recommendations or even specific hardware configurations to address this. Consider a separate, smaller panelboard. If you only have a few 3-phase loads that require auxiliary contacts, it might be more economical to install a separate, smaller panelboard specifically for those loads. This would avoid the space constraints in your main NF panel. Draw it out. Sketch out your panel layout and breaker arrangements. This will help you visualize the phase rotation and identify any potential problems. Prioritize Clarity and Safety
Whatever approach you choose, make sure it's clear, well-documented, and safe. Avoid configurations that could lead to confusion or miswiring in the future.
In summary: The acceptability of adjacent breakers with different phase rotation in your scenario depends entirely on the nature of your loads. Single-phase loads, no problem. Three-phase loads requiring consistent rotation, a problem. Carefully consider your load requirements and choose the solution that best balances panel space, installation cost, and future maintainability. Flag for review