Overhead vs Underground Electrical Service

Power reaches a house one of two ways: overhead, on conductors from a pole, or underground, through a buried lateral from a transformer or pedestal. Most existing homes have whichever their neighbourhood was built with, and most new subdivisions are built underground.

The differences are real, and the conversion question comes up often enough to be worth answering properly.

The comparison

Overhead service

The utility's service drop runs from a pole to a point of attachment on your building, then down (or through the roof) via the service mast, entering at the weatherhead. See meter socket and service entrance explained.

Advantages: cheaper to install and to repair, faults are visible and usually quick to fix, and no excavation is involved for anything.

Disadvantages: the exposure is the whole problem. Wind, ice loading, falling branches and vehicle strikes on poles account for a large share of weather-related outages. And the mechanical pull of the drop is carried by your mast — which is why storms produce so many torn-off masts, each needing an electrician and usually a permit.

Maintenance on your side:

• Check the mast is plumb and firmly attached
• Check the weatherhead is intact and the drip loop is present
• Call the utility about vegetation growing into the drop — many trim at no charge. Never prune around a service drop yourself. Those conductors are not protected by anything on your side

Underground service

A service lateral runs buried from a transformer, pedestal or handhole to your meter, usually rising through a conduit riser to the socket.

Advantages: immune to wind, ice and falling branches; nothing visible; no mast to be torn off; no vegetation conflict.

Disadvantages:

• Much higher installation cost — trenching, conduit and conductors
• Slower repairs. A fault has to be located, then excavated, then repaired, then backfilled. An overhead fault is often visible from the road
• Vulnerable to digging. This is the main cause of underground service damage, and it's entirely preventable
• Flooding, in areas where water gets into the conduit system
• Harder to upgrade. Pulling larger conductors means either an oversized conduit installed originally or new trenching

Maintenance on your side: very little, which is part of the appeal. Watch the conduit riser and meter socket for damage and corrosion, and know roughly where the lateral runs.

Call 811 before you dig

The single most important rule with underground service.

Before any excavation — fence posts, a deck footing, a tree, a garden bed, a trench for a garage feeder — call 811. It's free, it's required, and it marks buried utilities on the property.

A service lateral is energized and unprotected by any overcurrent device you control. Striking one is potentially fatal, as well as expensive and disruptive. Locates take a few business days, so plan ahead rather than deciding to dig on a Saturday.

This applies equally when you're trenching for a detached building — see feeding a detached building.

Converting overhead to underground

The question people ask, usually for appearance or storm resilience.

It's a utility project, not something an electrician does alone. It typically involves:

1. Utility engineering and approval — they design the lateral, confirm the connection point, and quote their portion
2. Trenching from the connection point to the house, which may cross driveways, landscaping, sidewalks or the street
3. Conduit and conductors installed to the utility's specification
4. A new service entrance arrangement — the mast comes off, and the meter socket may need replacing or relocating
5. Permits and inspection
6. Cutover — a service interruption while it's switched
7. Restoration of everything the trench crossed

Cost is substantial and depends heavily on distance, what the trench has to cross, and your utility's policy. There's no useful ballpark — the same conversion can differ by an order of magnitude between a short run across a lawn and a long one under a driveway and a street.

Who pays: policies vary. Conversion requested by a homeowner for preference is typically largely at the customer's expense. Some utilities cost-share, some run area conversion programs, and the rules differ when a road project or development forces the change. Ask your utility for their written policy before planning around it.

Worth combining with: if you're doing a service upgrade anyway, the incremental cost of converting is lower than doing it separately. Same for a major renovation with the driveway already up. See service upgrade vs panel replacement and electrical panel upgrade cost.

Does it affect your service capacity?

Not directly. Capacity is set by the weakest link across the whole path — transformer, drop or lateral, service entrance conductors, meter socket, main disconnect and panel busbar. Either configuration can be built to any residential rating.

But it does affect how easy an upgrade is later. Increasing an overhead service means new drop conductors and often a new mast — disruptive but straightforward. Increasing an underground service may mean pulling new conductors (easy if the conduit is oversized) or new trenching (expensive if it isn't).

If you're installing a lateral, oversize the conduit. It's the cheapest future-proofing available, and it matters more as houses add EV charging, heat pumps and batteries. Work out where you'll be with the home electrical load calculator and see Electrical panel upgrade.

Reliability in context

Underground genuinely reduces weather-related outages at your service. But your power also depends on the distribution system upstream — and if the neighbourhood feeder is overhead, an underground lateral to your house doesn't protect you from a tree taking that feeder down.

If outage resilience is the actual goal, the money often goes further on:

• A generator — see portable vs standby generator and how to size a home generator
• A home battery — see whole home battery backup and do you need a home battery
• A transfer switch or interlock — see transfer switch explained

Undergrounding your own lateral is an expensive way to buy resilience you may not actually gain.

The bottom line

Underground service is more reliable in storms and invisible; overhead is far cheaper and faster to repair when it does fail. Neither limits your service capacity, but underground is harder to upgrade later unless the conduit was oversized — so oversize it if you're installing one. Converting is a utility-led project with substantial cost and a policy-dependent split, best combined with a service upgrade or major renovation. And with an underground lateral, call 811 before you put a shovel anywhere.

Related: who owns what on your electrical service.