A lot of Montgomery County homes are still running on the same 100-amp service panel they had when they were built in the 1950s and ’60s — and a heat pump, an EV charger, and a finished basement later, that box is out of room. David Williams Electric upgrades 100-amp services to 200 amps across Bethesda, Rockville, Silver Spring, Potomac and the rest of the county, pulls the Montgomery County DPS permit, and gets it inspected right the first time. You get the price before the work starts, and a 100% satisfaction guarantee behind it.
Why so many Montgomery County panels are out of room
Drive through the older parts of Silver Spring, Kensington, or the streets off Old Georgetown Road in Bethesda and you’re looking at houses wired for a 1960 electrical load: a stove, a furnace fan, and a couple of window units. Those homes were never planned for a 50-amp EV charger in the garage, an electric heat pump, a hot tub on the deck, or the second-floor primary suite someone added in 2015.
The tell is usually the panel itself — a 100-amp box (or, in the genuinely old Wheaton and Takoma-adjacent housing, a 60-amp fuse panel) with no open breaker spaces, a tangle of double-tapped breakers, or a federal-era panel that home inspectors flag on sight. When you’re tripping the main every time the AC and the oven run together, the fix isn’t another breaker — it’s more service. Upgrading to a 200-amp panel gives the house the headroom Montgomery County’s renovation-and-electrify trend actually demands.
What a 100A-to-200A upgrade actually involves
A service upgrade is more than swapping a box on the wall. We replace the meter base, the main service panel, and the grounding and bonding so it meets current code — and in Montgomery County that means coordinating the disconnect and reconnect with Pepco, which serves the whole county. We size the new panel and breakers to the home’s real load, label every circuit clearly, and leave you with open spaces for whatever comes next, whether that’s a Germantown townhouse adding an EV charger or an Olney rancher finishing its basement.
Older homes here come with their own wrinkles. If your house has aluminum branch-circuit wiring — common in homes built from the mid-’60s into the ’70s around Gaithersburg and Montgomery Village — we address it correctly with pig-tailing using ALUMACONN connectors at the device terminations, not a cosmetic cover-up. Knob-and-tube or cloth-wrapped conductors near the panel get evaluated honestly before anything gets energized.
Permits, Pepco, and the county inspection — handled
A panel upgrade in Montgomery County is a permitted job, full stop, and the electrical permit can only be pulled by a contractor holding a valid Maryland Master Electrician license. David Williams Electric carries Maryland license #11734, files through the county’s DPS ePermits system, and schedules the inspection for you. One detail that trips up out-of-county crews: Montgomery County’s residential inspectors are cross-trained, so the building, electrical, and mechanical inspections are scheduled together for the same visit — we plan the job around that so you’re not waiting on a re-trip.
We coordinate the Pepco disconnect, do the changeover, and get you back on power the same day in the vast majority of homes. You’re not left chasing the county or the utility — that’s our job, and it’s baked into the up-front price.
Up-front pricing and 30+ years on county homes
You’ll know the full cost of your panel upgrade before we touch a wire — no “we’ll see what we find” surprises after the meter’s already pulled. David Williams has spent 30-plus years inside Montgomery County’s housing stock, from the brick capes of Rockville to the larger custom homes off Falls Road in Potomac, so the quote reflects what your specific house actually needs.
Every upgrade is code-compliant, inspected, and backed by our 100% satisfaction guarantee. If something isn’t right, we make it right.
Frequently Asked Questions
Do I really need a 200-amp panel, or can I just add breakers?
If your panel still has open slots and the main isn't overloaded, sometimes a circuit can be added. But if you're tripping the main, out of breaker spaces, or planning an EV charger, heat pump, or addition, you've outgrown a 100-amp service — and on the older Bethesda and Silver Spring homes that's usually the real story. Upgrading to 200 amps fixes the cause instead of patching the symptom.
Do I need a permit for a panel upgrade in Montgomery County?
Yes. A service-panel upgrade always requires an electrical permit from Montgomery County DPS, and only a Maryland-licensed Master Electrician can pull it. We hold Maryland license #11734, file through the county's DPS ePermits system, and handle the inspection so the job is signed off correctly.
Will my power be off all day during the upgrade?
For most homes the power is out only for the few hours it takes to swap the meter base and panel and coordinate the Pepco disconnect and reconnect. In the large majority of Montgomery County homes we have you back on power the same day.
My house has aluminum wiring — can you still upgrade the panel?
Yes. Aluminum branch-circuit wiring shows up in a lot of mid-'60s-to-'70s homes around Gaithersburg and Montgomery Village. We handle it the right way, with pig-tailing using ALUMACONN connectors at the device terminations, and we'll flag any other older wiring near the panel before energizing the new service.
How much does a panel upgrade cost?
Every home is different — the run from the meter, the condition of the existing service, and any aluminum or older wiring all factor in. That's exactly why we quote you the full price up front, after looking at your actual panel, so there are no surprises once the work starts.
Serving Montgomery County
David Williams Electric provides electrical panel upgrades throughout Montgomery County, including Rockville, Bethesda, Silver Spring, Gaithersburg, Germantown, Potomac, Olney. Explore all Montgomery County electrical services or learn more about electrical panel upgrades across Maryland. Call (410) 781-4357 for a free, up-front quote.
