At RKM Homes we include EV-ready wiring as a standard option during the rough‑in phase so homeowners in the Denver area aren’t left with a costly retrofit later. Early in the design process we confirm the preferred charger location (garage wall, garage column, or driveway/patio), review the main service capacity, and size circuits to match the owner’s intended charging speed. Planning at that stage lets us route conduit and breakers efficiently through framing and masonry, avoid cutting finished surfaces, and coordinate any needed service upgrades or subpanel placement before drywall and insulation go in.
Technically, Level 2 charging requires a dedicated 240‑volt circuit sized for continuous load per the National Electrical Code (125% of the charger’s continuous current). In practice that means a common 32‑amp EVSE is supplied from a 40‑amp breaker with #8 AWG copper conductors, while a 40‑amp EVSE is wired from a 50‑amp breaker with #6 AWG. During construction we usually run a 3/4″ or 1″ conduit (EMT or PVC) from the main or garage subpanel to the intended charger location, pull THHN conductors and an equipment grounding conductor, and leave a pull string for future upgrades. We also prewire options for a hardwired EVSE or a NEMA 14‑50 receptacle, label the circuit in the panel, and reserve nearby panel space so a charger can be added without a major electrical rework.
We handle permits and inspections through the local jurisdictions and coordinate with our licensed electricians to meet AFCI/GFCI and other code requirements, as well as any utility notifications if a service increase is needed. Beyond the basic circuit we also consider practical site details — weatherproof outlets, mounting height clearances, routing to avoid obstruction by garage doors, and futureproofing for higher‑amp charging, solar, battery storage or smart load management systems. Pre‑wiring during construction reduces cost and disruption compared with retrofits, and gives homeowners a clean, code‑compliant foundation for immediate or future EV charging.
Do I need to increase my home’s electrical service to support current and future EV charging?
As a custom home builder, I always start with a residential load calculation during design so we know whether the planned main service will handle a Level 2 charger plus all the usual house loads. Many older or smaller homes on 100A services struggle if you add a 40–48A EV circuit while running electric range, dryer and HVAC; for that reason we recommend 200A as a baseline for new custom homes. If you expect multiple EVs, high‑power chargers, or large electric HVAC/heating loads, consider planning for a 400A service or a 200/200 split service with room in the panel for future expansion.
Practically speaking, decide early whether you want a dedicated 240V Level 2 outlet (typically a 40–60A circuit) or the flexibility to install higher‑amp charging later. If you aren’t ready to wire the final charger, leave physical capacity in the panel (spare breaker spaces and conduit routes to the garage), and show reserved capacity on the electrical plan so the electrician and permitting authority know the intent. Another cost‑saving option is to install an energy management system or smart load controller that lets a standard 200A service safely share capacity between house loads and charging, avoiding an immediate service upgrade while still supporting a Level 2 charger.
What you should do as a homeowner: ask your builder to include an electrician in preconstruction meetings, request a formal load calculation, and get estimates from both the electrician and the utility for a service upgrade if needed. Make decisions early enough to avoid rework—moving a meter, upgrading the service mast, or adding a new service lateral can add time and several thousand dollars if done late. We typically include a 200A allowance in our base specs and will upgrade to larger service on request once you confirm expected EV usage, so budget and schedule for that choice up front.
How do builders rough‑in an EV‑ready conduit, plan cable routing, and pick the best charger location during construction?
We start by nailing down the exact parking spot and charger mounting preference before framing — whether the owner wants the charger on an interior garage wall, an exterior wall beside the driveway, or a freestanding post. Measure the likely cord reach based on the vehicle’s charging port location and room for snow, doors, and storage so the charger will be mounted where the cable naturally reaches the car without draping across walkways. For garages we typically aim for a mounting height that’s easy to access for most users (roughly waist to chest height) and keep shelving, bikes, or HVAC equipment out of that zone so the charger and cord remain usable.
For the actual rough‑in we run at least one continuous, smooth conduit from the electrical area to the chosen charger location and always pull a second empty conduit as insurance for future upgrades. Long sweep bends make cable pulls far easier than sharp 90s; minimize the number of turns, terminate conduit runs in an accessible pull box or chase behind the finished wall, and leave a pull string in every empty conduit. Use durable conduit materials for exposed or exterior sections, protect conduits that cross the slab or foundation with sleeves, and coil extra length in the pull box so an electrician can make clean terminations later.
On site we document every conduit run and endpoint: we mark the finished wall location, note distance from fixed reference points (door jams, corners), and photograph both ends before finishes are closed. Conduit should be installed before slab pours or drywall so it can be positioned cleanly — we coordinate timing with trades to avoid accidental crushing or encasement of pulls. Before finishes we ask the homeowner to confirm charger location and cord reach; that final check saves costly relocations and makes the future electrician’s job straightforward.
Should I pre-wire for 120V (Level 1) or 240V (Level 2), and what amp rating should the EV circuit be?
From my experience building custom homes in Denver, plan for Level 2 240V charging unless you truly expect only occasional plug-in use. Level 1 (120V) on a standard 15–20A circuit will work for overnight top‑ups but only delivers roughly 3–5 miles of range per hour; Level 2 at 240V delivers much faster charging — roughly 7.7 kW (32A) to 11.5 kW (48A), which commonly translates to about 20–35 miles of range per hour depending on the vehicle. For practical home use and resale value, homeowners should think in terms of the charger output they want (32A vs 40A vs higher) rather than just the voltage.
A key electrical rule to plan around is that EV charging is treated as a continuous load, so breakers and conductors must be upsized by about 125% of the charger’s continuous current. That means a charger that draws 32A requires a 40A breaker and typically #8 AWG copper conductors; a charger that draws 40A requires a 50A breaker and typically #6 AWG copper conductors. When you discuss options with your electrician or builder, use those examples — “I want to support a 32A charger (install a 40A circuit with #8) or future 40A charger (install a 50A circuit with #6)” — so the wiring, conduit and breaker are correctly sized during rough‑in.
What you can ask us (or your electrician) to do during construction: pick the charger level you want now, or choose to future‑proof by installing conductors and conduit sized for at least a 40A output (i.e., a circuit capacity served by a 50A breaker and #6 wiring), run a dedicated 240V branch to your preferred parking spot (or install a NEMA 14‑50 receptacle if you prefer flexibility), and clearly label the circuit in the panel. These practical choices — deciding 120V only versus 240V Level 2, naming the amp target, and having the right conductor and breaker sizes pulled during rough‑in — avoid costly retrofits later and make your home ready for current and next‑generation EVs.
How should panel layout, subpanel options, breaker space, and disconnects be planned for EV charging?
Where the EV circuit lands in the service panel is one of the easiest decisions to get right up front: reserve two adjacent full-size spaces for a 2‑pole 240V breaker (this prevents awkward tandem installations and ensures a common‑trip/handle‑tied breaker can be used). Ask your electrician during rough‑in to leave those spaces blank, label them “EV Charger,” and run a conduit knockout in the panel toward the garage so a future subpanel or feeder can be tied in cleanly. If your main panel is already crowded, plan on a small garage subpanel fed from an available full‑size breaker in the main — it keeps the charger wiring local and makes future expansion much easier.
For homeowners deciding between a main‑panel breaker vs. a dedicated garage subpanel, think about immediate needs and growth. A single Level 2 charger can often be served from a 50–60A breaker in the main if you have the space; if you want room for a second charger, battery charging, or workshop loads later, specify a 60–100A subpanel in the garage and have the electrician pull appropriately sized feeder conductors during rough‑in (as a rule of thumb, 60A feeders are commonly #6 copper, 100A feeders are typically #3 copper or larger when using aluminum — confirm with your electrician). Having the subpanel location decided now also lets us place it where conduit runs are shortest and where a future hardwired EVSE can be mounted without long cable runs.
Disconnects and breaker type are practical safety choices you should decide before drywall: insist on a two‑pole common‑trip breaker or a breaker with a handle tie for the EV circuit, and discuss whether your jurisdiction or installer prefers a local lockable disconnect at the charger. Don’t accept a shared or multi‑wire arrangement for an EV circuit — it should be dedicated and clearly labeled on the as‑built panel schedule. Finally, ask the electrician to leave space for any manufacturer‑required protective devices and to note the EV circuit location on the electrical drawings so future electricians or inspectors can find and service it without tearing into finished walls.
What permits, code requirements, utility coordination, and electrician should I consider when pre-wiring an EV charging circuit?
On our projects we always start by pulling the required electrical permits as part of the rough‑in package — the local electrical permit covers the conduit stub, rough wiring notes, and the final inspection for the installed charger circuit. Ask your builder or electrician up front which local code cycle they follow (many jurisdictions now reference the latest NEC plus local amendments) and require a signed load calculation and plan set for the permit submittal. Expect at least a rough‑in inspection and a final inspection; plan the timeline so the rough inspection happens before drywall so the inspector can see the conduit and any panel work.
Contacting the utility early is one of the most practical steps you can take. If the service needs an upgrade, a new meter base, or a dedicated meter for EV charging, utilities often have lead times and fee estimates; we notify the utility during design so any transformer or service extension requirements are identified before trenching. Also ask about time‑of‑use rates, demand charges, and whether the utility offers load‑management program requirements that affect how the charger must be installed or metered.
Hire a licensed electrician with new‑construction EV experience who will manage the permit process and utility coordination for you. When vetting contractors, request proof of license/insurance, references for recent new‑home EV installs, and a written scope that explicitly states who will pull permits, handle inspections, and coordinate with the utility if a service upgrade is needed. Insist the contract include contingencies and pricing for potential utility work so there are no surprises, and make sure the electrician provides as‑built documentation and final sign‑offs needed for your Certificate of Occupancy and any rebate or inspection records.