Industrial Electrical Services · Pillar Guide

Power distribution upgrades, built for the next 30 years.

MCCs, transformers, sub-panel additions, busway upgrades — the industrial power distribution scope that supports facility growth and equipment changes.

Written bySteven Lockhart

Reviewed byAlex Towery · C-10 #989290

Updated: June 2026 · Read: 7 min

11 yrsMarin electrical work

C-10CSLB licensed contractor

1st passInspection rate

48 hrTypical estimate turnaround

Key Takeaways

Distribution upgrades are typically triggered by capacity exhaustion (existing service can't support new loads), voltage class changes (208V to 480V for larger equipment), or compliance issues (aging equipment, arc flash mitigation).
Motor Control Centers (MCCs) consolidate motor starters, VFDs, and protective devices into a structured cabinet — proper MCC design is the difference between maintainable and chaotic industrial electrical.
Transformer sizing is load-based with derating for harmonic content and operating temperature — undersized transformers run hot and fail; oversized ones waste capital.
Distribution upgrades require careful planning for production downtime — most are done in phases over a planned shutdown or extended weekend windows.
Arc flash studies and NFPA 70E compliance are increasingly required at major distribution upgrades — updated equipment with proper labeling protects workers.

Towery Electric — Power Distribution Upgrades.

01 — OverviewWhat Power Distribution Upgrades actually covers in Marin.

Industrial power distribution is the infrastructure between the utility connection and the production equipment. For a typical Marin light-industrial facility, that includes the main switchboard, possibly a step-down transformer (480V to 208V or 240V), motor control centers organizing the motor starters and protective devices, sub-panels feeding sections of the facility, and the conductor pathways (conduit, cable tray, busway) carrying power between them. Distribution upgrades happen when this infrastructure needs to grow, modernize, or be brought into compliance.

The decision triggers are usually obvious: a facility outgrows its existing service (production equipment additions exceed available capacity), an aging MCC needs replacement (parts unavailability, arc flash concerns), or a major equipment change requires different voltage (going from 208V to 480V for larger industrial equipment). The execution is intricate because production can't simply stop for days while infrastructure swaps happen — phased shutdowns and temporary feeds are typical.

Definition

'Industrial power distribution' is the electrical infrastructure between the utility service entrance and the equipment loads — including main switchboards, transformers, motor control centers (MCCs), sub-panels, and the conductors and pathways tying them together.

MCC fundamentals

A Motor Control Center is a structured cabinet containing motor starters, VFDs, control transformers, protective devices, and metering — consolidating all the motor controls for a facility (or a section of it) into one organized assembly. Modular bucket design allows individual motor controls to be removed and serviced without affecting others.

Transformer sizing

Transformers step voltage between service-side (480V) and load-side (208Y/120V) for facilities mixing both voltage classes. Sizing per kVA load with derating: ~80% loading for harmonic content (high in modern facilities with VFDs), ~90% for thermal operating margin. Oversized transformers waste capital; undersized transformers fail.

For the broader context this guide supports, see our Industrial Electrical Services overview.

Explore the Full Guide

Power distribution work clusters by equipment type and by upgrade trigger.

Three guides to read first

Cornerstone

MCC Design & Installation

Modern MCC architecture — bucket modular design, control transformer sizing, VFD integration, arc flash mitigation.

Explore the guide →

Critical

Industrial Transformer Upgrades

When transformer upgrade is needed, sizing methodology, primary/secondary work, and PG&E coordination.

Explore → Major

Industrial Service Upgrades

Service-side capacity upgrades for facility expansions — PG&E coordination, switchboard replacement, phased cutover.

Explore →

Browse the Full Library

Equipment types

Voltage & capacity

Compliance

Process

02When distribution upgrades are needed.

Three common triggers drive most industrial distribution upgrade work.

Capacity exhaustion

Facility wants to add equipment but existing service is at or near capacity. Triggers full load study; result is often service upgrade plus new MCC capacity or new sub-panels.

Voltage class change

Facility was originally 208V single-phase or 208Y/120V; new equipment requires 480V 3-phase. Solution: add 480V service (new utility coordination) or add step-up/step-down transformers.

Aging equipment + arc flash

MCCs and switchboards from the 1970s-1980s often have parts unavailability issues, lack modern arc flash mitigation, and have documented safety risks. Replacement during major facility refresh is common.

03Why phased shutdowns matter for distribution upgrades.

Distribution upgrades touch infrastructure that most of the facility depends on — you can't just take the main switchboard offline for a day. Real distribution upgrade execution requires phased shutdown planning: which loads can move to a temporary feed during the upgrade window, which loads must stay energized, what the cutover sequence looks like, and how the facility returns to normal operation.

We typically engineer distribution upgrades for completion over a planned weekend or extended holiday shutdown when the facility is normally idle. For 24/7 operations, phased approaches use temporary generators or alternate feeds to keep critical loads running while the work happens. The scheduling complexity is real — but it's predictable, and good planning prevents the scramble that turns a 36-hour planned shutdown into a 5-day production loss.

04MCC architecture — bucket modular design.

Modern MCCs use bucket modular design — individual motor controls are bucket assemblies that plug into a common bus structure.

Bucket organization

Each motor or motor group gets its own bucket with starter, OCPD, control transformer, and metering. Buckets are sized 1/6, 1/4, 1/2, or full unit width depending on motor HP and components.

Common bus and control

Vertical bus distributes 3-phase power to buckets; horizontal bus across the MCC ties multiple sections together. Control wiring runs through gutter spaces; some MCCs include integrated PLCs for distributed control.

Modern features

Arc flash mitigation (light detection, fast tripping), remote monitoring via communication networks, predictive maintenance via thermal sensors integrated in buckets. Modern MCCs are dramatically more maintainable than 1970s-1980s designs.

05Why NFPA 70E and arc flash matter at upgrades.

Arc flash hazards are the most serious electrical safety risk in industrial work. An arc flash event releases extreme heat, pressure, and light energy — capable of fatal injuries even at distances of several feet. NFPA 70E (Standard for Electrical Safety in the Workplace) governs how facilities mitigate this risk through equipment selection, labeling, work practices, and PPE requirements.

Major distribution upgrades are the right time to implement arc flash mitigation: replacing older equipment with arc-flash-rated equipment, installing arc flash relays that detect and trip on light/pressure signatures, and ensuring all equipment carries current arc flash labels per a coordination study. Arc flash studies (performed by licensed engineers using software like ETAP or SKM) calculate the incident energy at each piece of equipment and drive PPE requirements. Required at major upgrades; required by some insurance carriers; required by OSHA in certain contexts.

Frequently Asked Questions

How much does an industrial distribution upgrade cost?

Highly variable based on scope. A typical light-industrial Marin/Sonoma facility distribution upgrade — replacing an aging 800A MCC, updating panel work, adding arc flash labeling — runs $85,000-$220,000. Larger upgrades (service entrance work, transformer additions, multiple MCCs) scale from there. We size each project specifically based on load study, equipment selection, and phasing requirements. Arc flash study and coordination study run separately ($4,800-$18,000) and are increasingly required.

How long does a distribution upgrade take?

From contract signature to operational completion: typically 12-26 weeks for typical light-industrial scope. The bulk of calendar time is equipment lead time (MCCs are typically 8-16 weeks lead time from order), engineering drawings (4-8 weeks), and PG&E coordination if service work is involved. On-site install work is concentrated in 1-2 phased shutdown windows totaling 3-7 working days. Production downtime is typically the planned shutdown window only.

Do we need an arc flash study?

If you're doing a major distribution upgrade, almost certainly yes. NFPA 70E (and now OSHA enforcement) requires arc flash hazard assessment for facilities with electrical equipment. Major upgrades — new MCCs, switchboard replacements, service-entrance changes — are the right time to implement. Studies cost $4,800-$18,000 depending on facility complexity and result in equipment labeling, PPE requirements, and (sometimes) recommendations for arc flash mitigation equipment. Some insurance carriers now require current arc flash studies for renewal.

What's the difference between an MCC and a regular panel?

MCCs (Motor Control Centers) are designed specifically for motor controls — bucket-modular construction allowing individual motor starters, VFDs, and protective devices to be installed, removed, and serviced as plug-in assemblies. Regular panels (panelboards) are simpler distribution panels with breakers feeding general loads. Industrial facilities use MCCs for motor controls (because they organize the motor starters and allow service without total shutdown) and panels for general lighting and receptacle loads.

Will our production stop during the upgrade?

Not entirely. We engineer distribution upgrades for phased shutdowns — typically a single weekend or holiday shutdown window when production is normally offline. For 24/7 operations, we use temporary feeds (generators or alternate utility connections) to keep critical loads running while the work happens. The actual production-impacting downtime is usually 36-72 hours for a typical upgrade, planned weeks in advance. We share the detailed shutdown plan with operations management well before the work date.

Do you handle the PG&E coordination for service upgrades?

Yes — for industrial service upgrades involving PG&E (new transformers, increased service capacity, voltage class changes), we manage the full coordination process. PG&E's industrial process has multiple handoffs: service request, planner assignment, engineering review, transformer specification, install scheduling, and final cutover coordination. Realistic timeline from contract to install ready: 12-20 weeks. We share the timeline at contract signing and update at each PG&E milestone.

How We Reviewed This Page

Reviewed against current California Electrical Code (Title 24, Part 3) and 2023 NFPA 70 (NEC) provisions applicable to the topic.
Pricing ranges reflect actual 2026 Towery Electric quote data from Marin County jobs — not third-party industry averages.
Permit and inspection timing reflects current AHJ practice in Novato, San Rafael, Mill Valley, and unincorporated Marin County as of mid-2026.
Technical review by Alex Towery, founder and C-10 #989290 holder, with 11+ years of California electrical work.
All factual claims about code requirements were verified against primary sources (CSLB, CARB, PG&E, AHJ) at time of publication.

References

This guide reflects Towery Electric's professional standards as a California-licensed C-10 electrical contractor and is for general information. Site conditions, panel configurations, code amendments, and permit-authority requirements vary; final scoping, sizing, and code compliance for your specific address are determined on a paid site assessment. We follow California Electrical Code (Title 24, Part 3) and applicable NFPA 70 (NEC) editions adopted by your AHJ.