Ask IES Guides

Panels & Service Upgrades

Plain-English guides to electrical panel upgrades, 200-amp service upgrades, subpanels and fuse boxes in California, from a licensed C-10 electrician.

Your electrical panel is the heart of your home's wiring, and it's worth knowing a little about it. These guides walk through panel upgrades, subpanels and old fuse boxes in plain English. If something here sounds like your house, we're always happy to take a look.

Guides in this section 3

Panels & Service Upgrades

How panel upgrades work

Signs you need a new panel, panel swap vs 200-amp service upgrade vs subpanel, permits, utility coordination, timeline and IES starting-at prices.

Read guide Panels & Service Upgrades

Main panel vs subpanel: when does a subpanel make sense?

What a subpanel does and does not do, when it beats a new main panel, garage and shop subpanels, and when you need a service upgrade instead.

Read guide Panels & Service Upgrades

Should I replace my fuse box?

Are fuse boxes dangerous? What goes wrong with old fuse panels, insurance questions, and what replacing a fuse box with a breaker panel involves.

Read guide

Helpful tools

Tool

Can my panel handle it? (EV, heat pump, hot tub)

Quick, rough check of whether a 100 to 200 amp panel can handle a new EV charger, heat pump or hot tub, using a simplified NEC 220.82 load calculation.

Open tool Tool

Problem panel and recall checker

Check whether your electrical panel brand has a recall or a known problem history: Federal Pacific Stab-Lok, Zinsco, Challenger, Pushmatic, fuse boxes and more.

Open tool Tool

Wire size calculator

Free wire size calculator: enter amps, copper or aluminum, and distance to see the minimum AWG by NEC 310.16 ampacity and for 3% voltage drop. Rough guide.

Open tool
Need it done?

We’re a family-run, licensed C‑10 electrician in Auburn.

More sections

General information for California homes. Local rules and inspectors can vary. Not a substitute for an on-site inspection.