A feeder upgrade for an EV charger means increasing the capacity of the feeder, the conductors and breaker supplying a subpanel, so that the subpanel can support the EV charger’s load when its existing feeder is too small. It is one solution when you want to add a charger to a subpanel that lacks enough capacity, short of upgrading the whole service. Understanding what a feeder upgrade is helps you see one option for adding EV charging when a subpanel is the constraint.
Here is what a feeder upgrade for an EV charger is.
What a feeder is
A feeder is the set of conductors (and the breaker protecting them) that carries power from the main panel to a subpanel. The feeder’s size determines how much capacity the subpanel has to distribute to its circuits. For example, a 60-amp feeder gives a subpanel 60 amps of capacity. So the feeder is the supply line that sets the subpanel’s total capacity.
What a feeder upgrade does
A feeder upgrade increases the capacity of that supply by installing a larger feeder (larger conductors and a correspondingly larger breaker) to give the subpanel more capacity. For example, upgrading a subpanel’s feeder from a smaller size to a larger one raises the subpanel’s total capacity, creating room for additional loads like an EV charger. So a feeder upgrade is about enlarging the subpanel’s supply so it can support more.
When it is needed for an EV charger
A feeder upgrade may be needed for an EV charger when you want to add the charger to a subpanel that does not have enough spare capacity on its current feeder. If the subpanel is where the charger should go (for example, in a garage), but its feeder is too small to support the charger’s load alongside the subpanel’s existing loads, upgrading the feeder provides the needed capacity. This is an alternative to sourcing the charger elsewhere or using load management.
Feeder upgrade vs other options
A feeder upgrade is one of several ways to address a subpanel that is too small for a charger:
- Feeder upgrade: enlarge the subpanel’s supply for more capacity
- Load management: add the charger within the existing capacity by managing loads
- Smaller charger: choose a charger that fits the existing capacity
- Different source: run the charger’s circuit from the main panel if it has capacity.
Which is best depends on the situation, including whether the main panel has capacity to supply a larger feeder. A licensed electrician determines the right approach.
It depends on the main panel too
An important consideration is that a feeder upgrade requires the main panel and service to have enough capacity to supply the larger feeder. Increasing a subpanel’s feeder draws more from the main panel, so the main panel must have the spare capacity for it. If the main panel is also constrained, a feeder upgrade alone may not be enough, and a broader service upgrade or load management may be needed. A licensed electrician assesses the whole picture, the subpanel, the feeder, and the main panel, to determine whether a feeder upgrade works.
A feeder upgrade for an EV charger means installing a larger feeder to a subpanel so the subpanel has more capacity to support the charger, used when the subpanel’s existing feeder is too small. It is one option among load management, a smaller charger, or a different circuit source. Because it draws more from the main panel, it requires the main panel to have capacity. A licensed electrician assesses the system and determines whether a feeder upgrade is the right solution.
Stella Electric performs feeder and panel upgrades and installs EV charging for homeowners across the Baltimore area and throughout Maryland, with flat-rate pricing and no overtime charges. If your subpanel needs more capacity for a charger, we can help. Financing is available on qualifying projects.
