What Is a DCC for an EV Charger? Can It Help Avoid a 200-Amp Service Upgrade?
You’ve purchased an electric vehicle and now you want to install a Level 2 charger at home.
Then you look at your electrical panel and see 100 amps.
Does that mean you automatically need to upgrade your home to a 200-amp electrical service before installing an EV charger?
Not necessarily.
Depending on your home’s existing electrical demand, the charger you want to install and the electrical system itself, an EV energy management system may provide another option.
One product commonly used for this purpose is a DCC.
But what exactly does a DCC do, and when does installing one make sense?
What Is a DCC?
A DCC is an electric vehicle energy management system designed to manage the electrical load created by EV charging.
In simple terms, think of it as a traffic controller between your home’s electrical demand and your EV charger.
The system monitors how much electricity the home is using.
When household electrical demand becomes too high, the DCC can temporarily prevent the EV charger from drawing power. Once sufficient electrical capacity becomes available again, charging can resume automatically.
This allows EV charging to be managed without allowing the combined electrical demand to overload the home’s service.
Why Does This Matter for Homes With 100-Amp Service?
Many older homes in Ottawa have a 100-amp electrical service.
That service supplies all of the existing electrical loads in the home. Adding a Level 2 EV charger introduces another significant electrical load.
However, having a 100-amp service does not automatically mean the service is inadequate for EV charging.
The home’s existing electrical demand first needs to be evaluated.
For EV charger installations on a 100-amp service, TYFAR requires the home’s highest hourly electricity usage from the previous 365 days as part of the load assessment.
If sufficient capacity is available, an EV charger may be installed without an energy management system or service upgrade.
If there isn’t enough available capacity for the proposed charger, that’s when alternatives such as a DCC become worth considering.
What About a Brand-New Home With No Electricity Usage History?
A brand-new home presents a different challenge.
With an existing home, historical electricity usage can help us assess the demand on a 100-amp electrical service. A newly built home doesn’t yet have 365 days of electricity usage history to work with.
In this situation, the electrical load may need to be evaluated using the home’s installed electrical equipment.
And that’s becoming increasingly important as newer homes rely on electricity for more of their energy needs.
Modern homes may include:
- Heat pumps
- Electric auxiliary or backup heating
- Electric water heaters
- Electric ranges and dryers
- Air conditioning
- Other high-demand electrical equipment
A heat pump can be very efficient during normal operation. However, electric auxiliary or backup heating can represent a significant electrical load when determining the home’s service requirements.
When a new home has a 100-amp service and no historical usage data, load management is often the practical choice for adding EV charging, particularly in homes with several large electrical loads.
An approved EV energy management system can control the EV charging load based on the electrical demand of the home.
Depending on the home and the equipment being installed, the other option may be upgrading the electrical service to provide additional capacity.
Planning an All-Electric Home?
As homes become increasingly electrified, EV charging needs to be considered alongside the home’s other major electrical loads.
Heat pumps, backup electric heating, water heating, cooking appliances and EV charging can all contribute to the home’s electrical demand.
Don’t assume that because a home is brand new, its electrical service automatically has enough available capacity for the EV charger you want to install.
Service size, heating equipment, charger requirements and future electrical loads all need to be considered.
How Does a DCC Work?
Imagine you’re charging your vehicle overnight.
At the same time, your home may have other large electrical loads operating, such as:
- Electric heating
- An electric range
- A clothes dryer
- A water heater
- Air conditioning
- Other high-demand electrical equipment
A DCC monitors the home’s electrical demand.
If demand reaches the system’s configured threshold, power to the EV charging circuit is temporarily interrupted. Your other household electrical loads continue operating normally.
When the home’s demand drops sufficiently, the DCC can automatically allow EV charging to resume.
You don’t have to stand beside the electrical panel turning your charger on and off.
The energy management system does the work automatically.
Does a DCC Mean I Don’t Need a 200-Amp Service Upgrade?
Potentially — and that’s one of the main reasons these systems are used.
Without load management, a homeowner whose existing service cannot accommodate the proposed EV charging load may believe the only solution is upgrading the entire electrical service.
In some homes, an approved energy management system can provide another option.
That can make a DCC worth considering before automatically assuming a 200-amp upgrade is necessary.
However, a DCC isn’t automatically the best solution for every home.
The existing service, electrical panel, charger requirements, available panel space and installation conditions all need to be considered.
A Full Panel and Insufficient Electrical Capacity Are Not the Same Problem
This is an important distinction.
Homeowners sometimes use “full panel” and “not enough power” to describe the same problem.
They’re actually two different things.
A home can have sufficient electrical capacity for an EV charger but have no available breaker spaces in the electrical panel.
Another home might have several empty breaker spaces but insufficient electrical capacity for the proposed charger.
A DCC is primarily an energy-management solution.
It does not create additional breaker spaces inside an electrical panel.
If your electrical panel is full, that issue must also be evaluated when planning the installation.
Can a DCC Work With a 48-Amp EV Charger?
Potentially, but this is where the exact equipment and installation matter.
A 48-amp EV charger operating at full output normally requires a 60-amp branch circuit.
Some DCC equipment can accommodate configurations involving a 60-amp EV charging circuit and a 100-amp main service. However, this depends on the specific equipment, its approved configuration and the electrical installation.
It should not be assumed that every DCC, 100-amp service and 48-amp charger can automatically be combined.
The electrical contractor needs to evaluate the charger, service, panel and energy management equipment as a complete system.
This is one reason it’s helpful to provide the make, model and specification sheet for your EV charger when requesting a quote.
DCC or 200-Amp Service Upgrade?
There’s no universal answer.
A DCC may make sense when the existing electrical service is otherwise suitable and the primary issue is accommodating the additional EV charging load.
A 200-amp service upgrade may make more sense when additional electrical capacity is needed for other current or future loads.
For example, future plans might include:
- A second EV
- Additional electric heating
- A heat pump
- A hot tub
- Electric water heating
- Additional appliances
- A renovation or addition
The goal isn’t simply to choose whichever option sounds cheaper.
The goal is to determine which solution makes sense for the home today and what the homeowner plans to add in the future.
Do I Need a DCC Just Because I Have a 100-Amp Service?
No.
This is one of the biggest misconceptions surrounding residential EV charging.
A 100-amp service doesn’t automatically require a DCC.
It also doesn’t automatically require a 200-amp service upgrade.
The home’s existing electrical demand and the proposed charging equipment need to be evaluated first.
If sufficient capacity is available, neither may be necessary.
What Information Does TYFAR Need?
When requesting an EV charger installation quote, providing good information upfront helps us evaluate your options.
We typically ask for:
- Photos of your electrical panel
- A wider photo showing the panel and surrounding area
- Photos of the proposed charger location
- Photos showing possible wiring routes
- The EV charger make, model and specifications
- Information about finished and unfinished areas along the wiring route
- For a 100-amp electrical service, the highest hourly electricity usage from the previous 365 days
If you’re buying a brand-new home without historical electricity usage, let us know. We can take that into consideration when reviewing the electrical service and available EV charging options.
From there, we can determine whether additional information or a site visit is required.
For a complete look at the installation process, read our guide to EV Charger Installation in Ottawa: What to Expect From Quote Request to Final Inspection.
Don’t Assume You Need a Service Upgrade
If you have a 100-amp electrical service and have been told — or simply assumed — that installing a Level 2 EV charger means immediately upgrading to 200 amps, it’s worth having the installation properly assessed first.
A service upgrade may ultimately be the right solution.
But depending on the home and charger, load management through an approved EV energy management system may provide another option.
And if you’re buying a brand-new, highly electrified home, it’s worth thinking about EV charging before the vehicle is sitting in the driveway. Heat pumps, backup electric heating and other large electrical loads can affect the capacity available for charging.
TYFAR Electric can evaluate your electrical service, proposed charger and installation requirements to help determine the appropriate solution.
Planning a Level 2 EV charger installation in Ottawa? Request a quote and send us your panel and charger information to get started.