Okay, I understand the situation, even without the picture. You're describing a common RV power inlet box configuration, but you're questioning the grouping of all the neutral wires from different amp circuits on a single, isolated neutral bar.

The Short Answer: Yes, it is generally allowed and safe under specific conditions.The Explanation and Considerations


Neutral Function

The neutral conductor in an electrical system is a return path for current back to the source (power company transformer). In a properly wired system, the neutral carries the imbalance of current between the hot legs in a multi-wire branch circuit, or the full current of a single phase circuit.2.

Shared Neutral Bar

It's perfectly acceptable to connect all neutral wires (20A, 30A, and 50A circuits) to a single, isolated neutral bar within the RV power inlet box as long as the neutral bar is rated for the combined ampacity of all circuits feeding it.3.

Isolated Neutral Bar is Key

The fact that the neutral bar is isolated is important. This means it is not bonded to the enclosure of the box. This is often required in RV electrical systems for safety reasons (to prevent a potential difference between the RV chassis and the ground).4.

Capacity of the Neutral Bar

The neutral bar must be large enough to handle the combined maximum current that could flow through it. This is typically determined by the sum of the ampacities of the individual breakers feeding the branch circuits. In your case, you would need to ensure that the neutral bar is rated to handle at least 100 amps (20 + 30 + 50). Most reputable RV power inlet boxes are designed with this capacity in mind.5.

NEC and RV Standards

RV electrical systems are typically governed by National Electrical Code (NEC) Article 551 and RV industry standards like those from the Recreational Vehicle Industry Association (RVIA). These codes generally allow the sharing of a neutral bar in this type of setup, provided it meets the ampacity requirements and is properly isolated.6.

Why It Works (and is Potentially Better)

Grouping the neutrals on a single, appropriately sized, isolated bar simplifies the wiring and allows for a central point for neutral connections. As long as the bar is rated appropriately, there is no safety issue. It can also help ensure a lower impedance neutral connection which can be beneficial.

Important Considerations and Checks



Check the Neutral Bar Rating

Absolutely verify the current rating of the neutral bar itself. It should be stamped or labeled on the bar or in the product documentation. If you cannot find the rating, do not proceed until you can confirm it with the manufacturer. If it is not rated for at least 100 Amps total it is not acceptable.

Tight Connections

Ensure all neutral wires are securely and tightly connected to the neutral bar. Loose connections are a major cause of electrical problems.

Wire Gauge

Make sure that the incoming neutral conductor feeding the bar is sized appropriately for the total ampacity of the circuits. It should be the same gauge as the incoming hots coming in on the 50 amp connection.

Grounding

The grounding system is separate. Verify that the box is properly grounded according to the instructions and local electrical codes. This usually involves a separate grounding conductor that connects to the RV chassis.

In Summary

Grouping the neutrals from different RV circuits on a single, isolated neutral bar is typically permissible, provided the neutral bar is appropriately sized (rated for the combined ampacity), properly isolated, and all connections are secure. Always double-check the rating of the neutral bar and follow all applicable electrical codes and safety guidelines. If you're unsure about any aspect of the wiring, consult a qualified electrician.

Disclaimer: I am an AI and cannot provide definitive electrical advice. This information is for general guidance only. It is crucial to consult with a qualified electrician for any electrical work, especially in RVs, to ensure safety and compliance with local codes. Incorrect wiring can be dangerous and could cause fire, electrocution, or damage to your RV. Flag for review