Do I Need an Electrical Panel Upgrade?

Most homeowners arrive at this question one of two ways. Either something keeps tripping, or they have just been told that the thing they want to install will not fit on their existing service.

Both are legitimate reasons to look at it. But panel size on its own is a poor guide, and it is worth understanding what actually decides the answer before anyone quotes you.

The signs that genuinely matter

Some of these are inconvenience. Some are safety. They are not the same thing.

Capacity signs

• Breakers tripping regularly, particularly when a large appliance starts or when two run together
• No empty slots left in the panel
• Double-tapped breakers — two circuits landed on a device designed for one, which is a sign somebody previously ran out of room and improvised
• 100-amp service or less in a home with modern appliances
• A planned addition — a car charger, heat pump, induction range, hot tub or accessory dwelling unit

Safety signs

These are a different category and warrant a call rather than a plan:

• Warmth or discolouration on the panel cover
• Buzzing, crackling or a burning smell
• Scorch marks around breaker handles
• Breakers that will not reset
• A Zinsco or Federal Pacific panel, which we recommend replacing regardless of capacity

Why panel size does not answer the question

This is the part that surprises people.

A 100-amp service in a home with gas heating, a gas water heater and a gas range may have considerable headroom. A 200-amp service in an all-electric home with a pool and two vehicle chargers may have none at all.

The number on the main breaker tells you the ceiling. It tells you nothing about how much of that ceiling is already committed.

There is a second reason the intuition fails: household loads do not all run at once. Your oven, dryer, air conditioner and car charger essentially never peak simultaneously. If you simply added up every nameplate rating in a modern house, you would conclude that almost every home in Los Angeles needs a service upgrade — which is plainly not the case.

What a load calculation actually does

The electrical code defines a procedure for this, and it is not an estimate.

The calculation accounts for:

• Floor area of the dwelling
• Fixed appliances — water heater, range, dryer, dishwasher and so on
• Heating and cooling equipment, taking the larger of the two since they do not run together
• Any new loads you intend to add
• Demand factors — the defined allowances that account for loads not running simultaneously

For existing homes adding new loads, there is a specific method that can use your actual historical consumption. That method often produces a more favourable answer than people expect, because it reflects how the house is really used rather than what it theoretically could draw.

The output is a number in amps, and that number determines your service size. It is also what the inspector checks, which is why getting it right up front keeps a project moving.

What the big appliances draw

Useful for intuition, though remember these are not simply summed:

Appliance	Typical draw
Level 2 EV charger	32–48A
Induction range	30–50A
Heat pump (whole home)	15–40A
Electric dryer	30A
Heat pump water heater	15–30A
Conventional electric water heater	20–30A

Two things worth noticing. A car charger is usually the largest single item — and it is a continuous load, which means its circuit must be sized above its rating. And a heat pump water heater draws considerably less than the conventional electric tank it replaces, which is part of why they suit retrofits.

200 amp or 400 amp?

For most single-family homes, 200 amps comfortably covers electrifying heating, water heating and one vehicle.

400 amps is generally for:

• Large homes with substantial simultaneous load
• Several vehicle chargers
• An accessory dwelling unit on the same service
• Properties with workshop, well or pool equipment
• Homes planning significant future expansion

Going larger than you need is not free — the service entrance, meter socket and utility connection all scale with it. The calculation is what settles it.

Sequence everything at once

The most common expensive mistake we see is electrifying one appliance at a time.

Someone adds a car charger this year. A heat pump water heater the next. A heat pump the year after. Each is quoted independently, and somewhere in that sequence the service runs out — at which point the upgrade happens anyway, but now with work already installed around it.

If a heat pump, a water heater or a charger is anywhere in your five-year thinking, say so at the start. Sizing the service once around the whole plan costs a fraction of discovering the limit appliance by appliance.

What the work involves

1. Load calculation and quote — establishes whether you need an upgrade and what size.
2. Permit — required for a service change, and it brings an independent inspector.
3. Utility coordination — LADWP or Southern California Edison disconnects and reconnects. This usually sets the timeline.
4. Installation — new panel, and typically service entrance conductors, meter socket, mast and grounding brought to current code. Power off for several hours.
5. Inspection and energisation — inspector signs off, utility reconnects.

The physical work is normally a single day. The scheduling around it is longer.

Why quotes differ so much

Almost always scope, not markup. Ask specifically what is included:

• Is the service entrance conductor being replaced, or reused?
• Is the meter socket included?
• Does the mast need replacing?
• What grounding and bonding work is required to meet current code?
• Is the panel moving location, which adds substantial work?
• Does the utility require an overhead to underground conversion?
• Are arc-fault and ground-fault breakers included where code requires them?
• Is the permit in the price?

A quote that is materially cheaper than the others usually excludes something on this list. It is worth asking which.

The short version

Panel size alone will not tell you whether you need an upgrade — a load calculation will, and it is the only defensible basis for the decision.

If you are seeing any of the safety signs above, or you have a Zinsco or Federal Pacific panel, the answer is fairly clear regardless of capacity.

And if you are planning to electrify anything else in the next few years, work it out once for the whole plan rather than one appliance at a time.