Kan ik twee circuits op één stroomonderbreker aansluiten?

Circuit breakers are the unsung heroes of modern electrical systems, silently protecting homes and businesses from overloads, short circuits, and potential fires. A common question among homeowners and DIY enthusiasts is: “Can I run two circuits from one breaker?” While the idea of consolidating circuits might seem practical for saving space in a panel or reducing costs, the answer is nuanced and requires a deep understanding of electrical engineering principles, safety standards, and National Electrical Code (NEC) regulations.

This article explores the technical feasibility, risks, and code-compliant alternatives for managing multiple circuits, with a focus on ensuring safety and reliability. By the end, you’ll understand why combining circuits is rarely advisable—and what solutions exist when panel space is limited.

Understanding Circuit Breakers: Types and Functions

Wat is een stroomonderbreker?

A circuit breaker is an automatic switch designed to protect an electrical circuit from damage caused by excess current. It interrupts the flow of electricity when it detects an overload (too much current over time) or a short circuit (a sudden surge due to a fault). Modern homes use three primary types:

• Miniature Circuit Breakers (MCBs): Protect against overloads and short circuits in individual circuits.
• Aardlekschakelaars (RCCB's): Detect ground faults or leakage currents to prevent electric shocks.
• RCBOs (Residual Current Breakers with Overcurrent Protection): Combine RCCB and MCB functionalities.

Each breaker is calibrated to a specific amperage (e.g., 15A, 20A) and voltage (120V or 240V). Single-pole breakers handle 120V circuits, while double-pole breakers manage 240V appliances like dryers or HVAC systems.

The Feasibility of Combining Circuits

When Is It Technically Possible?

In rare cases, two circuits can share a single breaker, but this practice is heavily restricted by the NEC. Here are the exceptions:

1. Multi-Wire Branch Circuits (MWBCs) – An MWBC uses a shared neutral wire to serve two 120V circuits on opposite phases of a 240V system. This setup requires a double-pole breaker to ensure both hot wires disconnect simultaneously. If one circuit overloads, the shared neutral could overheat, posing a fire risk.
2. Tandem Breakers – Some panels accept tandem (or “split”) breakers, which fit two circuits into one slot. These are code-compliant only if the panel manufacturer explicitly permits them.
3. Pigtailing in the Panel – If a breaker terminal allows two wires, or if you pigtail (join) the hots inside the panel, the combined load becomes a single circuit. However, this method is risky unless both circuits are lightly used and their combined load never exceeds the breaker’s rating.

Risks of Combining Circuits

1. Overloading and Fire Hazards – Every breaker has a thermal-magnetic trip mechanism calibrated to its rated amperage. Combining circuits increases the risk of sustained overcurrent, which can melt wire insulation, damage appliances, or ignite fires. For example, a 20A breaker supplying two 15A circuits could theoretically draw 30A—far beyond its capacity.
2. Code Violations – The NEC prohibits shared neutrals without handle-tied breakers (NEC 210.7) and forbids overloading dedicated circuits (e.g., kitchens, bathrooms). Violations can void insurance claims or complicate home sales.
3. Operational Inconvenience – If two circuits share a breaker, a fault in one will shut off both. Imagine a bathroom outlet tripping a breaker that also controls a refrigerator—a nuisance at best, a food-safety hazard at worst.

Code-Compliant Alternatives

1. Install a Subpanel – A subpanel adds circuit capacity without replacing the main panel. It’s ideal for garages, workshops, or home additions. By installing a 60A subpanel, you can split one circuit into multiple dedicated ones.
2. Use Tandem Breakers – If your panel supports them, tandem breakers double your circuit capacity. However, they’re not universal—consult the panel’s labeling or manufacturer guidelines.
3. Upgrade to a Larger Panel – Older homes often have 100A panels, while modern systems require 200A. Upgrading provides ample space for new circuits and enhances safety.
4. Dedicated Circuits for High-Load Appliances – The NEC mandates dedicated circuits for refrigerators, microwaves, and HVAC systems. Never combine these with general lighting circuits.

Case Study: A Real-World Mistake

A Reddit user once described a condo where kitchen outlets were wired to two 15A circuits with intact breakaway tabs on the receptacles. This allowed up to 30A to flow through a single outlet, bypassing both breakers’ protections. The solution? Remove the tabs, split the circuits, and label them clearly.

When to Consult an Electrician

While DIY electrical work might seem cost-effective, mistakes can be deadly. Licensed electricians understand:

• Local code amendments
• Load-calculation formulas
• Proper grounding and bonding techniques

For example, aluminum wiring (common in mid-century homes) requires special connectors to prevent fires.

Conclusie

Running two circuits from one breaker is not recommended except in code-approved scenarios like MWBCs or tandem breakers. The risks of fire, code violations, and appliance damage far outweigh the convenience of saving panel space. Instead, opt for safer solutions like subpanels, dedicated circuits, or panel upgrades.

About VIOX Electric

VIOX Electric specializes in high-quality circuit protection devices, including MCBs, RCCBs, and RCBOs. Our products are engineered for durability and compliance with global safety standards. Explore our catalog at viox.com or contact our team for personalized solutions.

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