An electrical service refers to the entire system that brings electricity from Merrimac Municipal Light into a building. It includes the service drop (overhead wires) or service lateral (underground wires), the meter, the main breaker panel, and all the wiring that distributes power throughout the home or business.
What Do 100 Amp, 200 Amp, or 400 Amp Services Mean?
The number of amps (amperes) represents the capacity of your electrical service—the amount of electrical current your system can safely handle at once.
AMPS
100-Amp Service
- Common in older homes or small residences.
- Can handle basic appliances but may struggle with high-demand devices like central air conditioning or electric heating.
- Suitable for homes with gas heating and appliances.
AMPS
200-Amp Service
- Standard for modern homes.
- Provides enough power for larger houses, central air conditioning, electric water heaters, and multiple high-wattage appliances.
- Allows for future expansion (e.g., electric vehicle charging or additional circuits).
AMPS
400-Amp Service
- Needed for very large homes or businesses with high power demands.
- Can support multiple HVAC systems, electric heating, large workshops, or
multiple subpanels. - Sometimes installed as dual 200-amp panels instead of a single 400-amp panel.
How to Know What You Need
- Small homes (under 1,500 sq. ft.) → 100-amp may be sufficient.
- Standard modern homes (1,500-3,000 sq. ft.) → 200-amp is ideal.
- Large homes (3,000+ sq. ft.) or high-demand electrical loads → 400-amp service is recommended.
If you’re upgrading or building a new home, it’s always good to consider future needs (EV charging, home additions, solar, etc.) when choosing service size. MMLD recommends that you consult an electrician to determine if your service is sufficient for your home. Please make sure that your electrician receives the proper permits to make the installation.
How to know if it’s time to upgrade your home’s electrical service
1. Frequent Circuit Breaker Trips
If your breakers trip often, it may indicate that your electrical system is overloaded.
2. Flickering or Dimming Lights
Lights that flicker or dim when you use appliances can signal an outdated electrical panel or insufficient wiring – PLEASE CALL THE LIGHT DEPARTMENT COULD BE A BIGGER ISSUE.
3. Outdated Electrical Panel (Fuse Box or Low Amp Panel)
If you have a fuse box instead of a breaker panel, it’s time for an upgrade.
4. Burning Smell or Scorch Marks on Outlets
This could indicate overheating, faulty wiring, or potential fire hazards.
5. Limited or No Grounded (Three-Prong) Outlets
If your home still has two-prong outlets, your system may not be properly grounded, which is a safety issue.
6. Use of Too Many Extension Cords or Power Strips
If you rely heavily on extension cords, your home may not have enough outlets, which suggests an outdated system.
7. Installation of Major Appliances
Adding high-power devices like electric stoves, HVAC systems, or EV chargers may require an upgraded panel.
8. Home Renovations or Additions
If you’re remodeling, adding rooms, or finishing a basement, your electrical system may need to be expanded.
9. Older Home with Original Wiring
If your home is 40+ years old and still has knob-and-tube wiring or aluminum wiring, upgrading to modern wiring is strongly recommended.
10. Electrical Shocks or Buzzing Sounds
If you feel a shock when touching an appliance or hear buzzing near outlets, this could mean faulty wiring or grounding issues.
If you notice any of these signs, consult a licensed electrician to evaluate your system and determine if an upgrade is needed. MMLD is not allowed to go into customers’ homes – therefore, upgrades and analysis of your service needs to be done by licensed electrician.