Romex vs Conduit for an EV Charger Circuit

Electrical equipment and wiring in a residential installation — Illustrative photo.

This question usually arrives attached to a price difference between two quotes. One electrician has priced cable stapled through the framing; the other has priced conduit down the garage wall. Neither is cutting corners -- they are reading different requirements for the same run.

Where each one belongs

Wiring method by location
Run	Usually
Inside finished walls, dry	Cable (NM-B)
Exposed on a garage wall	Conduit, where damage is a concern
Outdoors, any exposed length	Conduit -- PVC is standard for wet locations
Underground to a detached garage	Conduit, buried to the required depth
An unfinished basement ceiling	Either, depending on exposure and local rules
A city that restricts cable	Conduit, whatever the run looks like

Conduit is required in wet locations, underground and on exposed runs where physical damage is a concern; PVC is the standard for underground and wet locations, and EMT is the common indoor conduit. Per the published comparison cited below.

Cost, honestly

The published material figures are roughly $0.30 to $0.80 per foot for NM-B cable against $1.50 to $4.00 per foot for conduit with individual conductors pulled through it. Labor moves the same way: conduit has to be cut, bent, secured and then wired.

On a 60 ft run, materials only

Cable at $0.30-0.80/ft: roughly $18 to $48

Conduit at $1.50-4.00/ft: roughly $90 to $240

Add fittings, boxes and more labor hours for conduit

On a short indoor run the gap is small; on a long outdoor run it is the quote

Those are material ranges, not quotes, and they are the reason conduit turns up on outdoor jobs and cable turns up inside walls. Where an EV circuit is concerned, the run length usually matters more than the method: voltage drop and conductor material both move the number too.

What conduit buys beyond compliance

Upgradeability. New conductors can be pulled later -- worth real money if you might go from 40 A to 48 A.
Physical protection in a garage where things lean against walls.
A tidy exposed run, which matters on a finished wall.
Future circuits through the same path, if you size the conduit for it. Roughing in for a new build.

What does not change

The breaker. A 40 A charger is a 50 A circuit either way.
Conductor size. Set by current and distance, not by the method.
Charging speed. Identical.
The permit. Both are ordinary methods; neither avoids inspection. Permits.

The conduit types you will hear named

Which conduit goes where
Type	Where it is used
EMT	The common indoor conduit, including exposed garage walls
PVC	The standard for underground and wet locations
RMC	Rigid metal, where the strongest physical protection is wanted

From the published comparison cited below. Which one your run needs is set by the route and your local authority.

For an EV circuit the common pattern is simple: cable inside the walls to the garage, and conduit for anything exposed, outdoors or buried. A detached garage nearly always means PVC in a trench. Detached garages.

What to ask when two quotes differ

Which method are you quoting, and why that one? The answer should describe the route, not a preference.
Is any part of this run outdoors, buried or exposed? That is usually what forces conduit.
Does our jurisdiction restrict cable? Some cities do, and a local electrician knows immediately.
If conduit, what size? One step larger than the minimum is cheap now and valuable later.
Does the price difference reflect material, labor or both? It is usually both, and the split tells you what is really going on.

One question worth asking if conduit is quoted for a long run: size it one step larger than the minimum. The material cost is small, and it is the difference between pulling a heavier circuit later and digging the trench again.

FAQ

Questions people actually ask

Can I use Romex for an EV charger?

Inside finished walls, in dry locations, usually yes. Conduit is required in wet locations, underground and on exposed runs where physical damage is a concern -- and some cities restrict cable entirely.

Is conduit more expensive?

Yes. Published material ranges are about $0.30-0.80 per foot for NM-B against $1.50-4.00 per foot for conduit, plus more labor.

Does the wiring method affect charging speed?

No. Speed comes from the circuit and the charger, not from how the conductors are routed.

Which is better for a detached garage?

Underground runs use conduit, with PVC the standard for wet and buried locations. Detached garages covers the whole job.

Sources

Where these numbers come from

Romex vs conduit — WireRefWhere conduit is required (wet locations, exposed runs where physical damage is a concern, underground), which conduit type suits which location, and published material cost ranges of $0.30-0.80 per ft for NM-B cable against $1.50-4.00 per ft for conduit. Read 2026-09-27.
NEC Article 625: EV charging equipment — WireRef625.41 continuous load rated at 125%, 625.42 dedicated branch circuit and the energy-management exception allowing multiple chargers to share one circuit, 625.54 GFCI protection. Read 2026-09-27.
Charging Electric Vehicles at Home — U.S. Department of Energy, Alternative Fuels Data CenterInstallations must comply with local and state codes and permits may be required; an electrician can say whether a home has the capacity; outdoor installation and use are safe with outdoor-rated equipment. Read 2026-09-27.