How to Rewire Old Commercial Buildings on a Budget

Assess the Existing Electrical System

Before beginning any rewiring project, it's important to fully understand the existing electrical system in the building. This will help you identify any deficiencies, estimate costs, and develop a plan. Here are some key things I'd recommend:

Hire an electrician to do a thorough assessment of the current wiring, electrical panels, and devices. They can identify any safety hazards or code violations.
Map out the current circuit layout. Note which circuits go to which areas, the wire gauge used, and the amperage capacity. This will help plan for any relocated or additional circuits.
Inspect all electrical panels and meters. Check for corrosion, damaged breakers, insufficient capacity, or lack of empty breaker space for expansion.
Evaluate devices and fixtures. Are they outdated, inefficient, or at the end of their service life? This will impact what you may need to replace.
Assess the grounding system. Check that all equipment is properly grounded for safety.

Prioritize and Budget for Improvements

Once you understand the state of the existing electrical system, you can strategically plan and budget for needed improvements.

Address any safety hazards first. Rewiring should start with upgrades to meet basic electrical codes and safe practices.
Plan for increased capacity. Calculate total target capacity for lighting, equipment, HVAC, etc. to determine if higher amperage panels or wiring is needed.
Prioritize rewiring needs. Focus first on sections with old, damaged, or insufficient wiring. Then move to areas earmarked for upgraded fixtures or devices.
Consider electrical rates and incentives. Check with your utility company for potential rebates on energy efficient upgrades. Factor in projected cost savings.
Create a multi-year plan. Break major rewiring into phases spread over 2-3 years. Coordinate with other renovations or maintenance work.
Allocate a sufficient rewiring budget. Aim for 15-25% of total renovation costs depending on the building's needs.

Use Cost-Effective Rewiring Materials and Methods

To complete the rewiring affordably, research and use materials and methods aimed at reducing overall costs:

Use metal clad (MC) cable rather than conduits where allowed. It's up to 75% cheaper to install.
Choose lower cost panels such as loadcenters rather than distribution boards where appropriate.
Standardize devices and lights to bulk purchase the most common, economically priced models.
Install occupancy sensors to automatically control lighting in infrequently used areas.
Use prefabricated wiring assemblies like whips to connect fixtures. It reduces labor time.
Coordinate access to simplify routing. Plan wiring routing through easily accessible paths.
Combine multiple circuits in shared trenches. Digging fewer, larger trenches saves on labor time.
Phase work to avoid "ripple effects". Limit unexpected extra repairs by selectively rewiring one section at a time.

Leverage Electrical Contractor Resources

Don't take on more than you can handle. Electrical contractors can provide expertise and manpower to rewire buildings safely and cost-effectively:

Have contractors bid on your phased plan. This brings competitive pricing for the full multi-year project.
See if they have unused materials from other jobs they're willing to discount.
Ask about apprentice labor programs. Some companies use these programs which offer lower hourly rates.
Inquire if they have relationships with electrical supply vendors to get contractor discounts on materials.
Discuss options to reduce change order costs. For example, pre-purchasing extra supplies for later phases.
Use value engineering. See if they recommend alternative cost-saving rewiring methods acceptable under electrical codes.
Check for rebates contractors might offer. Many provide labor rebates when installing energy efficient lighting or devices.

Follow Proper Safety and Building Procedures

It's critical to follow all electrical codes and get necessary permits when rewiring commercial buildings:

Have licensed electricians perform all work to meet local and national electrical codes.
Pull any required building permits and have inspections done by the local building department.
Update electrical drawings with as-built conditions after work is complete.
Keep detailed rewiring records for future reference and maintenance.
Inform tenants ahead of any planned outages. Turn off only sections of electrical at a time.
Isolate and label any live wires not disconnected when working in a circuit breaker panel.
Use proper safety gear and techniques. Follow OSHA guidelines on electrical hazard safety.
Secure open panels and trenches. Prevent unauthorized access or tripping hazards.

By methodically evaluating, planning, budgeting, and properly executing rewiring, commercial property owners can upgrade aging electrical systems cost-effectively.