How to Replace Outdated Circuit Breakers in Your Commercial Building

Replacing outdated circuit breakers in a commercial building is an important safety measure that requires expertise and planning. As the owner or facilities manager, here is how I recommend approaching this project:

Evaluate the Existing Electrical System

Before replacing any breakers, it's essential to fully evaluate the current electrical system. Here are the key steps I take:

Consult Electrical Drawings and Panel Schedules

• Review electrical drawings to understand the full scope of the building's electrical system. Pay attention to the locations of panels, number of circuits, types of loads on each circuit, and voltage ratings.

• Examine the panel schedules to see the number, type, amperage, and voltage ratings of existing circuit breakers.

Inspect All Electrical Panels

• Visually inspect every panel for signs of damage, corrosion, overheating, or other issues.

• Check for double-tapped breakers, overfused circuits, and any improper or dangerous wiring conditions.

• Verify that all circuits are properly labeled. Rewire or re-label any circuits that are unclear.

Consider Load Requirements

• Evaluate if existing circuit breaker amperages can handle the connected loads. Overloaded circuits can overheat wires and cause fires.

• For new equipment, understand its voltage and amperage ratings to size replacement breakers appropriately.

Consult an Electrician if Needed

• If the electrical system is very complex or I am unsure about any conditions, I consult a certified electrician or engineer to evaluate the system prior to replacing breakers.

Select Appropriate New Circuit Breakers

When selecting replacement circuit breakers, properly matching voltage and amperage ratings is critical. I also consider:

• Breaker type - Choose the same circuit breaker type (e.g., single pole, double pole) as the original.

• Interrupting rating - For commercial buildings, the interrupting capacity should be 10,000 Amps or greater.

• Brand compatibility - Replacement breakers must be compatible with the existing electrical panel brand.

• Code compliance - All new breakers must comply with current NEC and local electrical codes. Common requirements include arc-fault (AFCI) and ground-fault protection (GFCI).

• Circuit labeling - Label all new circuit breakers clearly for safety.

Install New Breakers Safely

When installing replacement circuit breakers, I follow these best practices:

Turn Off Power and Verify It's De-Energized

• Locate the main breaker or disconnect switch that isolates the panel and turn off power to the entire panel.

• Use a non-contact voltage tester to double-check that ALL wiring in the panel is completely de-energized. This is a crucial safety step.

Remove Old Breaker and Clean Surface

• Unscrew and remove the old circuit breaker.

• Carefully clean the busbar surface where the new breaker will attach. Remove any dirt, corrosion or debris.

Install New Breaker According to Instructions

• Follow the breaker manufacturer's instructions to properly install and torque new breakers. Over-tightening can damage the breaker or busbar.

• Ensure the breaker amperage rating matches the previous breaker and circuit load requirements.

Restore Power and Verify Operation

• Restore power to the panel and verify proper operation of each new circuit breaker.

• Test GFCIs and AFCIs using their push-to-test buttons to ensure correct function.

Update Panel Schedules and Electrical Drawings

• Revise panel schedules and electrical drawings to reflect the changes. This maintains proper documentation.

With careful planning, inspection, and adherence to electrical codes and safety practices, outdated circuit breakers can be upgraded successfully. For large projects, partnering with a certified electrician is recommended. Proper breaker replacement is crucial for preventing fires and meeting modern safety standards.

Frequently Asked Questions

How often should commercial buildings inspect or replace circuit breakers?

• Circuit breakers generally last 10-20 years. I recommend thoroughly inspecting breakers every 5 years and replacing any showing signs of wear, damage or corrosion. All breakers should be replaced after 15-20 years as a precaution.

What are signs that a circuit breaker needs replacement?

• Frequent tripping, arcing sounds, warm/hot to touch, pitted/corroded contacts, failure to reset, or failure to trip during overload are signs a breaker should be replaced. Also replace any breaker of an obsolete type.

Are there any safety tips for shutoff and lockout/tagout procedures?

• Yes, proper lockout/tagout procedures are vital for safety. Shut off power at the main breaker or disconnect and lock it in the off position if possible. Post warning signs. Once power is confirmed off, proceed with caution as if the circuit is still live.

Can I upgrade from a fuse box to a circuit breaker panel?

• Yes, upgrading from an old fuse box to a modern circuit breaker panel is recommended for safety. This requires rewiring the whole electrical system and should only be done by a licensed electrician. All work must meet current NEC codes.

How do I know if I need additional circuits or larger amperage breakers added?

• If you are overloading existing circuits by adding new equipment and loads, the circuit breakers may need to be increased in amperage. Check your electrical code for required circuit capacity for new loads. Also consider adding dedicated circuits for large equipment rather than overloading existing circuits. An electrician can best determine if your system needs upgrades.

What tools do I need to replace a breaker?

• Basic tools include a voltage tester, screwdrivers, torque screwdriver, wire cutters, wire strippers, labeling machine, and safety gear like gloves and eye protection. Use insulated tools rated for the system voltage. Follow manufacturer's tool recommendations.