Home » Blog » What LA Property Managers Need to Know About Load Calculations for Multi-Unit Buildings

In Los Angeles, property managers juggle many responsibilities—from tenant relations and repairs to navigating city codes and keeping buildings insurable. But one of the most misunderstood (and often overlooked) responsibilities is ensuring that the electrical system is properly sized for the demands of the building.

Enter the load calculation: the foundation of any smart electrical design or upgrade.

Whether you’re managing a 10-unit complex in Silver Lake or a 40-unit property in Koreatown, understanding electrical load calculations is critical for safety, compliance, and long-term cost control. If your building is overloading its electrical service—or if the panel is sized based on outdated demand levels—you’re facing risks you may not even see: fire hazards, failed inspections, tenant complaints, and insurance issues.

This guide walks you through what load calculations are, how they apply to Los Angeles multi-unit buildings, and how RG Electric can help you ensure your property is wired for safety, compliance, and growth.

What Is a Load Calculation?

A load calculation determines how much electrical current (measured in amps) a building needs to operate safely and efficiently. It takes into account every power-using device on the property, including:

  • Lighting and general-use receptacles
  • HVAC systems
  • Elevators (if applicable)
  • Laundry facilities
  • Kitchen appliances
  • Water heaters
  • Electric vehicle (EV) chargers
  • Common area lighting
  • Security systems and access controls

The National Electrical Code (NEC) provides formulas and tables that electricians use to calculate load accurately. The goal is to ensure that your main panel and sub-panels are sized to handle peak demand without overload—and to plan for future expansions or upgrades.

In Los Angeles, these calculations must also meet LADBS requirements, which may include permitting and inspection steps.

Why Load Calculations Matter More in LA Multi-Unit Buildings

In single-family homes, underestimating the load might mean a few tripped breakers. But in a multi-unit apartment complex, the stakes are much higher. Here’s why:

1. Outdated Infrastructure Is Common

Many LA buildings were constructed decades ago, long before the era of flat-screen TVs, high-efficiency HVAC, smart devices, or EV chargers. Panels and service drops that were adequate in 1965 are now critically undersized. Panels and service drops

2. Insurance and Inspection Compliance

Underwriters are becoming increasingly strict about electrical systems. Buildings with undersized or outdated service may be denied coverage, or worse, have claims denied following an incident. Load calculations are often part of insurance audits and LADBS inspections.

3. Tenant Expectations Are Rising

Modern tenants expect to charge their car, run multiple appliances, and live in a tech-enabled space—without electrical hiccups. Inadequate service results in breaker trips, brownouts, and complaints that hurt tenant satisfaction and lease renewals. Charge Your Car

4. Cost-Efficient Planning

A thorough load calculation allows you to future-proof your property. Planning an EV charger rollout? Adding more HVAC capacity? Load calculations help you size your panels and service properly now, avoiding costly piecemeal upgrades later.

How to Perform a Load Calculation: Step-by-Step Overview

A licensed electrician begins by surveying every circuit and appliance in the building. This includes fixed and plug-in equipment, lighting, mechanical systems, and shared building resources. Each item is assigned a load value based on NEC tables and demand factors, then totaled to determine peak demand.

Load diversity—a calculation based on the fact that not all devices run simultaneously—is applied to arrive at a realistic service size. This final figure is used to determine the appropriate panel size (in amps) and whether additional service upgrades, transformers, or sub-panels are necessary.

For example, a 12-unit building with 100-amp service and aging appliances may actually require 400 amps once realistic demand is assessed. This is where most older properties fall short.

Common Errors Property Managers Make with Electrical Load Planning

One of the biggest mistakes is assuming the existing panel size is adequate simply because it “hasn’t failed yet.” This overlooks hidden stress on breakers, overheated wiring, and unseen capacity issues.

Other errors include:

  • Adding new appliances without load recalculations
  • Installing EV chargers without factoring in demand
  • Relying on outdated or estimated load values
  • Failing to document panel changes or load upgrades for LADBS or insurers

The Role of Sub-Panels in Load Distribution

Sub-panels are often used in multi-unit buildings to help distribute load across multiple systems and locations. For instance, one sub-panel might serve common areas like hallways and laundry rooms, while another is dedicated to tenant units.

This reduces demand on the main panel and allows for easier maintenance and safer load balancing. Sub-panels also simplify code compliance and allow for localized troubleshooting when issues arise.

Permitting, Compliance, and LADBS Requirements

In Los Angeles, panel upgrades and service increases must be permitted through the LADBS. This includes load calculations as part of the permit documentation, inspection after work is completed, and potentially coordination with the Department of Water and Power (LADWP) for service upgrades.

Failure to pull the proper permits can result in fines, delays, or forced tear-outs. RG Electric handles all aspects of this process for our clients, including preparing the required documents, submitting for review, and being present for inspection.

Case Study: Load Rebalancing in a 32-Unit Echo Park Building

One of our recent projects involved a 32-unit building where tenants were experiencing frequent blackouts during peak summer usage. Our inspection revealed that the building’s original 400-amp service was being exceeded daily.

We performed a full load calculation, installed two sub-panels to redistribute circuits, and coordinated a service upgrade with LADWP. After completing the work and passing LADBS inspection, the client saw a dramatic drop in tenant complaints and gained eligibility for improved insurance coverage.

How RG Electric Handles Load Assessments for Multi-Unit Complexes

We begin every project with an in-person assessment, during which we:

  • Evaluate all current usage and demand
  • Inspect panel conditions and labeling
  • Identify code violations or upgrade opportunities
  • Plan for future growth (EV, solar, HVAC, etc.)

Our electricians use NEC-approved load calculation methods and local expertise to size systems accurately. We document every step for compliance and provide property managers with reports that can be submitted to insurers or used for building permits.

Questions to Ask Your Electrician Before Any Panel Upgrade

Before you approve any panel upgrade or service change, ask:

  • What is the calculated peak demand for my building?
  • Will this panel meet code and insurance requirements?
  • Are we planning for future load increases (EVs, remodels, HVAC)?
  • How will the upgrade affect tenant access and service downtime?
  • Will you handle LADBS permitting and inspection?

A competent electrician will have clear answers to all of these questions—and if not, it’s time to call RG Electric.

Cost Factors and Timeline Expectations

Costs for load assessments and panel upgrades depend on:

  • Size and age of the building
  • Current panel condition
  • Need for sub-panels or rewiring
  • LADWP service upgrade requirements
  • Inspection fees and permitting time

Most projects range from $5,000 to $30,000 depending on scope. Timelines typically range from one to four weeks, including permitting.

Tips for Future-Proofing Your Electrical System

  • Always factor in EV charging and energy-efficient systems
  • Choose panels with extra breaker capacity
  • Install surge protection to protect the entire system
  • Label all circuits clearly and keep an updated electrical map
  • Reassess load after major renovations or tenant turnover

Call to Action

If you manage an apartment complex and aren’t sure your electrical system is up to the task, RG Electric can help. We perform detailed load calculations, system upgrades, and code-compliant installations that keep your tenants safe and your building compliant.

Call (323) 521-5131 or fill out the form on this website to schedule a consultation.


Disclaimer: Always consult a licensed electrician like RG Electric before making changes to your electrical system. Load calculations must comply with NEC and local LADBS regulations.

Expert Tips

Need an electrician near you? RG Electric has electricians on its board that acquire extensive experience in electrical installation and repairs. The tips we share reflect their expertise to help you avoid dangerous situations. Don’t hesitate to contact our local electricians for any questions or concerns regarding your wiring. We’ve got you covered!
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