7611 Fitch Lane
Baltimore, MD 21236
Generator Interlock Kits l Safe Power by Dynamo Electric
By Kenny Daniels
October 28, 2025
Stay powered and safe during outages. Learn how generator interlock kits keep your home running reliably. Installed by Dynamo Electric in Baltimore County, MD.
Keep the Lights On Safely: Why Every Maryland Home Needs a Generator Interlock Kit
Power outages always seem to happen at the worst possible time, a stormy night, a freezing winter morning, or right in the middle of making dinner. In those moments, having a generator can make all the difference. But having backup power is only half the equation. The other half is making sure it’s safe to use.
That’s where a generator interlock kit comes in and it’s one of the smartest, safest, and most cost-effective upgrades a Maryland homeowner can make.
At Dynamo Electric, LLC in Towson, we’ve helped hundreds of families install interlock systems that keep their lights on without the risk of back-feeding power or damaging their electrical system. This post will break down everything you need to know: how they work, why they’re safer than extension cords or manual transfer switches, and how to know if your home qualifies.
What Is a Generator Interlock Kit?
A generator interlock kit is a safety mechanism that allows you to connect a portable generator directly to your home’s electrical panel during a power outage, safely and legally.
It’s a small metal sliding plate that physically prevents your main breaker and generator breaker from being on at the same time. When power goes out, you flip off the main breaker, slide the interlock plate, and turn on your generator breaker. This setup ensures that your generator powers only your home, not the utility lines.
Without an interlock, power can “backfeed” into the grid, which is extremely dangerous for utility workers and can damage your generator or electrical system.
Why Homeowners Choose an Interlock System
- Safety First – Prevents back-feeding and ensures only one power source is active.
- Cost-Effective – Far less expensive than a full automatic transfer switch system.
- Convenience – Lets you power your home’s main circuits instead of running cords to individual appliances.
- Flexibility – Works with portable generators of various sizes, giving you more control during an outage.
- Code-Compliant – When installed by a licensed electrician like Dynamo Electric, your setup meets Maryland safety and electrical codes.
How an Interlock Kit Works
Here’s the basic flow of how an interlock system operates:
- Normal Operation: Your main breaker is on, supplying power from the utility company.
- Power Outage: The utility power fails, your lights go out.
- Generator Connection: You connect your portable generator to the outdoor inlet box (installed by Dynamo Electric).
- Switching Power: You turn off the main breaker, slide the interlock plate, and switch on the generator breaker.
- Backup Power Active: Your generator now powers selected circuits inside your home like lights, refrigerators, Wi-Fi, and furnaces.
- Utility Restores: Once the power is back, you reverse the process. turn off the generator breaker, slide the plate back, and turn on your main breaker.
Simple, safe, and effective, that’s the beauty of an interlock.
What You Can Power with an Interlock
The exact circuits depend on the size of your generator, but most homeowners prioritize:
- Refrigerator and freezer
- Sump pump
- Furnace or boiler
- Lighting circuits
- Wi-Fi and outlets for phones or laptops
- Garage door opener
During installation, Dynamo Electric helps you choose which breakers to power based on your home’s layout and generator size.
Why a Licensed Electrician Matters
Installing an interlock kit isn’t a DIY project. It involves modifying your main service panel and ensuring compliance with NEC (National Electrical Code) and local Maryland standards. Improper installation can lead to failed inspections or worse, electrical hazards.
At Dynamo Electric, our licensed electricians handle the entire process:
- Evaluate your panel brand (e.g., Square D, Siemens, Eaton, Cutler Hammer, etc.)
- Verify compatibility with UL-listed interlock kits
- Install a 30-amp or 50-amp power inlet box outside your home
- Wire and label circuits clearly for easy operation during an outage
- Test and verify safe operation before we leave
We make sure your system is clean, labeled, and ready when you need it most.
Interlock vs. Transfer Switch
Many homeowners ask whether an interlock or transfer switch is better. The answer depends on your needs and budget.
| Feature | Interlock Kit | Transfer Switch |
| Cost | $1,025 –$1,650 (installed) | $2,500–$3,500 (installed) |
| Operation | Manual switch between utility and generator | Manual or automatic |
| Circuits Powered | Entire panel or selected circuits | Selected circuits |
| Space Required | Uses existing panel | Requires extra equipment |
| Best For | Portable generator users | Standby generator owners |
For most Maryland homeowners who own a portable generator, the interlock system provides the perfect balance of safety and affordability.
Signs It’s Time to Add a Generator Interlock
- You already have a portable generator but use extension cords around the house
- You’ve recently experienced frequent outages or storms
- You upgraded your electrical service to 200 amps
- You want a safer, code-compliant way to connect your generator
- You are ready to upgrade your service (great time for two upgrades at once)
Dynamo Electric’s Process
When you call Dynamo Electric for an interlock installation, here’s what you can expect:
- Free Consultation & Estimate – We review your panel brand, generator size, and installation site.
- Professional Installation – Our licensed electricians install the inlet box, interlock, and necessary wiring.
- Testing & Walkthrough – We show you exactly how to use the system safely during an outage.
- Lifetime Craftsmanship Guarantee – As with all our work, your installation is backed by our lifetime workmanship warranty.
You’ll have peace of mind knowing your system is built to last and wired to code.
Frequently Asked Questions
Q: Do interlock kits meet code in Maryland?
Yes, when properly installed with a UL-listed kit by a licensed electrician, they meet Maryland and NEC requirements.
Q: Can I run my entire house on a portable generator with an interlock?
Usually no. You’ll run essential circuits only, depending on generator size (most handle 3,000–9,000 watts).
Q: How long does installation take?
Typically, 3–5 hours depending on panel access and wiring conditions.
Q: What brands of panels are compatible?
Most, including Square D, Siemens, GE, Cutler Hammer, and Eaton have UL-listed interlocks available.
Final Thoughts
Power outages are inevitable, but losing comfort and safety doesn’t have to be. A generator interlock kit is one of the smartest investments you can make to protect your home and family. It’s affordable, safe, and ready when you need it most.
Whether you live in Towson, Parkville, Lutherville, or Baltimore County, Dynamo Electric can install your interlock system with precision, clarity, and care.
Keep your power safe, your home protected, and your family comfortable — even when the lights go out.
