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Sub Panel Wiring for EV Chargers and Added Circuits

Chapter 01 · Panels & Service Entrance

Sub Panel Wiring for EV Chargers and Added Circuits

Licensed, insured, and permitted installs backed by a 1-year labor warranty.

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Sub Panel for EV Charger or Overloaded Main

A sub panel for an EV charger is one of the most common reasons homeowners call us, and it's a job that goes wrong more often than it should when handled by someone without a proper electrical license. Installing a 240V dedicated circuit for a Level 2 charger sounds straightforward until you open the main panel and find no available breaker slots, an undersized service, or aluminum branch wiring that needs evaluation before anything new is added. All Electric holds CO License #ME.0600978, carries full insurance, and pulls permits on every sub panel installation. The work is inspected, code-compliant, and backed by a 1-year labor warranty. Call (720) 951-4619 to schedule a same-day or next-day assessment.

Sub panel wiring isn't one-size-fits-all. The cost varies based on how far the new panel is from your main service, whether conduit needs to run through finished walls or an attic, the amperage required for your intended loads, and whether the main panel itself needs any work before a feeder can be added. A straightforward garage sub panel fed from an unfinished basement is a different scope than a detached workshop 100 feet from the house. We'll assess what your home actually needs, not upsell you on capacity you won't use. Financing is available for larger projects. Every job is different -- contact All Electric for an accurate estimate.

What a Sub Panel Installation Actually Involves

Six things that happen on every permitted sub panel job we complete.

01

Load Calculation First

Before any wire gets pulled, we calculate the existing load on your main service. If the main panel is already near capacity, adding a feeder for a sub panel can trip breakers repeatedly or cause nuisance shutdowns. We size the feeder correctly the first time.

02

Proper Feeder Sizing

The wire between your main panel and sub panel carries the full load of everything downstream. Undersizing it is a fire hazard. We size conductor and conduit to code for the amperage installed, not the minimum the inspector would pass.

03

Grounding and Neutral Separation

This is where unlicensed work gets dangerous. In a sub panel, the neutral bus and ground bus must be separated. Bond them together the way you do in a main panel and you've created a shock hazard. We get this right every time.

04

Permit and Inspection

We pull the permit before work starts and schedule the inspection. An uninspected sub panel is a problem at resale, for your homeowner's insurance, and for anyone who touches the panel after us. Don't skip this step.

05

EV Charger Circuit Integration

If the sub panel is going in specifically for a Level 2 EV charger, we install the dedicated circuit at the same time. No second visit, no coordination headache. The charger circuit is sized for your vehicle and EVSE manufacturer specs.

06

Labeled, Clean Finish

Every breaker gets labeled. Wiring is organized inside the enclosure. We treat the finished panel the same way whether it's in a finished basement or an unfinished garage. Mediocre work isn't something we're willing to put our license number on.

Common Scenarios

When a Sub Panel Is the Right Call

Four situations where a sub panel solves the problem more effectively than trying to add circuits to an overloaded main.

  1. 01

    Main Panel Has No Open Slots

    Tandem breakers are a band-aid. If your 200A main is full and you need two or three new circuits for an EV charger, a hot tub, or a kitchen remodel, a sub panel fed from the main is the cleaner, code-compliant solution.

  2. 02

    Detached Garage or Workshop

    A separate structure needs its own panel. Running individual circuits from the house to a detached garage is inefficient and sometimes not code-compliant depending on distance. A sub panel in the garage lets you add circuits locally without running wire back to the house each time.

  3. 03

    Basement or Addition Remodel

    Finishing a basement often means lighting circuits, outlet circuits, HVAC loads, and occasionally a wet bar or laundry connection. A sub panel in the basement keeps those circuits organized and makes any future work easier. It's a common part of a remodeling electrician scope.

  4. 04

    EV Charger on an Older Service

    A Level 2 home charger draws 32--48 amps continuously. Homes with 100A service and a full main panel often can't absorb that load without a service upgrade. A sub panel paired with a load management device can sometimes solve the problem without a full electrical panel replacement.

How It Works

Our Sub Panel Installation Process

  1. Step 1: Site Assessment

    We inspect the main service, measure available capacity, and confirm the route for the feeder. You'll know what needs to happen before we schedule anything.

  2. Step 2: Permitted Installation

    We pull the permit, install the panel and feeder, wire all required circuits, and separate grounding and neutral correctly. No shortcuts.

  3. Step 3: Inspection and Handoff

    The work gets inspected. We walk you through the finished panel, label everything, and confirm the EV charger or other new loads are functioning correctly before we leave.

Why homeowners trust us

Quick Facts About Sub Panel Wiring

All Electric -- CO License #ME.0600978 -- has installed sub panels across the Front Range for 9 years. Here's what every customer should know before calling any electrician.

  • Permits are not optional

    An unpermitted sub panel can void your homeowner's insurance and complicate a home sale. We pull the permit on every job.

  • Neutral and ground separation is code in sub panels

    Bonding them together -- common in DIY installs -- creates a shock hazard. This is the single most common mistake we correct.

  • Feeder wire size determines what you can run downstream

    A 60A feeder limits you to 60A total load. We size it for your actual needs, with room for future circuits.

  • 1-year labor warranty on every install

    If something we did fails within a year, we come back and fix it. No argument.

Daniel VargasOwner · Family-owned · Denver Local 4.9 · 468 Google reviews

Straight from Google

What Customers Say About Our Work

4.9468 verified Google reviews
Got the job done well, pleasant to work with.
Brian NicholsBrian NicholsSep 2026 · Google
All Electric is the best! Knowledgeable in fair and troubleshoot till they get the job done, if needed. Highly recommend 🙌🏽
gina dgina dSep 2026 · Google
Fantastic service. They showed up, assisted in the repairs, found the underlying issues and fixed them and then explained what those issues were in a manner that I could understand. Top service, as always.
Sean FrohlingSean FrohlingAug 2026 · Google
Same day service! Was here in 3 hours. Very honest and charge was kept at the minimum. Polite service as well.
Fred LudlowFred LudlowAug 2026 · Google
Very responsive. Easy to work with. Would definitely recommend to friends and family.
BritneyBritneyAug 2026 · Google
Electrician came out the next day after calling to install two light fixtures. Minimal issues and got them both installed successfully even though we have an old home. Pricing was reasonable to me. I will definitely be using them again for any similar needs!
Jillian L. CallaghanJillian L. CallaghanAug 2026 · Google
Awesome service. Quick prompt and very professional and knows the business. Daniel Vargas was the Master Tech. Accessed the problem and was quick to diagnose! Two faulty breakers. Highly recommend.
Michelle BakerMichelle BakerAug 2026 · Google
Daniel was great - solution-oriented, super-responsive, knowledgeable and really nice to work with - I will look to Daniel aand All Electric for future needs - thanks!
Travis BoganTravis BoganAug 2026 · Google
Read all 468 reviews

Sub Panel Wiring -- Frequently Asked Questions

Not answered here? Call (720) 951-4619 and ask the electrician.

How many amps should a sub panel for an EV charger be?
Most Level 2 home chargers draw 32--48 amps continuously, which means the circuit needs to be rated at 40--60 amps (the NEC 125% rule for continuous loads applies). The sub panel itself should be sized with room beyond that -- a 100A sub panel is common when additional circuits are planned. We'll confirm the right size for your specific charger and vehicle during the assessment.
Does a sub panel require a permit?
Yes, in every jurisdiction we serve. A sub panel involves a new feeder from the main service, new breakers, and new circuits -- all of which require a permit and inspection. An uninspected sub panel is a liability at resale and may not be covered by your homeowner's insurance if it causes a loss. All Electric pulls the permit before work starts, every time.
What's the difference between a sub panel and a main panel upgrade?
A main panel upgrade increases the total amperage coming into your home from the utility -- it involves coordinating with the power company and often replacing the meter base and service entrance. A sub panel adds a secondary distribution point inside your home, fed from the existing main. If your main service has enough capacity, a sub panel is faster and less disruptive than a full upgrade.
Can I run a sub panel to a detached garage for an EV charger and other circuits?
That's one of the most practical applications. A sub panel in a detached garage lets you run a 240V EV charger circuit, general-purpose outlets, and lighting from a single feeder rather than pulling individual circuits from the house for each load. The feeder needs to be sized for the combined load, and the conduit or direct-burial cable must meet local code for the installation method. We handle all of it.
How do I know if my main panel can support a sub panel feeder?
We check two things: available breaker slots for the double-pole feeder breaker, and whether the main service has enough unused capacity to support the load you're adding. Many 200A panels in older homes are already running near capacity. If yours is, we'll tell you honestly -- and discuss whether a load management approach or a service upgrade makes more sense before recommending a sub panel.
Why must the neutral and ground be separated in a sub panel?
In a main panel, the neutral and ground are bonded together at one point -- that's the grounding point for the entire system. In a sub panel, they must remain separate because the neutral wire is a current-carrying conductor between the two panels. Bonding them in the sub panel creates a parallel path for return current through the ground wire, which can cause nuisance trips, equipment damage, and shock hazards at metal enclosures. This is a code requirement under NEC 250.142.
Does a sub panel installation require a permit?
Yes, in every jurisdiction we serve. A sub panel involves a new feeder from the main service, new breakers, and new circuits -- all of which require a permit and inspection. An uninspected sub panel is a liability at resale and may not be covered by your homeowner's insurance if it causes a loss. All Electric pulls the permit before work starts on every job.
How do I know if my main panel has enough capacity for a sub panel feeder?
We check two things: available double-pole breaker slots for the feeder, and whether the main service has enough unused capacity to carry the added load. Many older 200A panels are already running close to capacity. If yours is, we'll tell you honestly and discuss whether a load management approach or a residential electrical service upgrade makes more sense before recommending a sub panel. Every job is different -- contact All Electric for an accurate estimate.

Schedule Your Sub Panel Assessment

All Electric -- CO License #ME.0600978 -- installs permitted sub panels sized for EV chargers, workshop loads, and home additions. 4.9 stars across 468 Google reviews. Online scheduling is available, or call (720) 951-4619 to talk through your project.

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