A full panel doesn't mean you need a bigger service

A lot of the calls we get about service upgrades start with the homeowner already certain they need one. The panel is full, or it looks old, or a contractor mentioned 200 amps in passing. Often they are right. Often enough to matter, they are not.

Here is how we actually work it out, and the three situations where the answer is genuinely no.

The three things that actually signal an upgrade

In roughly the order we see them:

1. Physical damage: a tree came down on the service, or there is rust or water getting into the equipment. This is the most obvious one and it is not subtle.
2. No space left. You are trying to add something, like an EV charger or air conditioning, and there is nowhere to land it.
3. Not enough amperage. An older home on a 100 amp service, trying to add a charger that wants another 40 or 50 amps. The capacity simply is not there.

Having 100 amps is not itself a problem

This is the one worth slowing down on, because it costs people the most money unnecessarily.

If you have a 100 amp service and a tree took out the mast, that does not mean you have to come back at 200. We can repair it and go back with 100. What decides it is a load calculation on the house and one question: are you adding anything?

If you are, then yes: go to 200 while the work is open, because doing it twice costs more than doing it once. If you are not, and you just want the damage put right, 100 amps is a legitimate answer.

If it's been working on 100 amp service for 20, 30 years, there's no reason why it can't continue to work on 100 amps.

Jimmy, owner, Good Times Electric

A full panel and a full service are different problems

People conflate these constantly, and they are not the same thing. A panel being out of breaker spaces is a container problem. A service being out of capacity is a supply problem. You can fix the first without touching the second.

Say you are on 100 amps and you want to add a 20 amp pump for a small pool. We do a whole-home load calculation, and it comes back showing you are still inside 100 amps. Then you do not need a bigger service. You need a bigger panel on the service you already have.

It doesn't automatically mean that you have to upgrade to a 200.

Jimmy, owner, Good Times Electric

What actually pushes a house over

These are the loads that start the conversation, because they are large and they are usually additions to a house that was not designed around them:

1. EV chargers, the most common one now, and typically another 40 to 50 amps.
2. Central heating and air, especially on older homes that never had it.
3. A larger electric water heater.
4. Additions, shops, hot tubs and pools.
5. Electric cooking, where a house is moving off gas.

Where remodeling actually sits

There is a widespread belief that remodeling a kitchen obliges you to upgrade your service. That is not quite how it works, and the distinction is worth having straight before anyone quotes you.

What a remodel obliges is that the work you are doing meets current code. Open the walls, move or add circuits, and that new work is held to today's standard, including the amendments San Antonio makes to the national code, which is part of what the permit and inspection are for. None of that, by itself, is a requirement to make the service bigger.

Whether the service has to grow is a separate question, answered the same way as every other case here: a load calculation. If what you are adding takes the house past what the existing service can carry, the service goes up. If it does not, it does not.

If you are not opening anything up, you are not obliged to bring an existing installation up to current code at all. It is when wires start moving that the question arises.

What happens if you just keep adding

Mostly, breakers trip. That is the system doing its job, and it is the outcome you want.

Older equipment is where it gets less comfortable. Current rules call for an emergency disconnect outdoors on one- and two-family homes, so first responders can kill the power without going inside. But that requirement came in with a recent edition of the code and applies to new and replacement equipment. An older installation is not retroactively obliged to have one, so plenty of houses around San Antonio do not.

Keep loading a system with no overcurrent protection in the right place and the failure moves upstream, to the feeders themselves.

If you keep going and adding with no over current protection, it could cause your main feeders to short out, which I've seen in the past.

Jimmy, owner, Good Times Electric

How we decide, in practice

We start with why you think you need one. Is this an EV? Is something not working? Those lead to different places.

Then we come out, look at the service you have, go over what you are trying to do, and run a load calculation on the house. That is what separates an upgrade from a repair, and it is not a judgment call. It is arithmetic on the actual loads.

Age of the equipment is the other input. A 30 year old panel is at the end of its service life, and we will tell you so regardless of what the load calculation says.

We don't mind going out and going over what it is that you're trying to do and help people out as much as we can.

Jimmy, owner, Good Times Electric