Dedicated Circuits and Subpanels
One breaker for one big load, or a whole second panel for the shop or casita, sized off a real load calculation.
What it is
A dedicated circuit is one breaker feeding one load, nothing else on the wire. A subpanel is a second panel fed from your main by one larger breaker, splitting that power into its own circuits at the garage, shop, casita, or a new tenant space. A hot tub, an RV pedestal, a welder, a well pump, or a pool pump wants its own circuit. A detached building with lights, receptacles, and a mini split wants a subpanel on a feeder, usually run underground in conduit. The main panel decides what's possible, so a load calculation comes first. A long run gets sized for voltage drop, not just the load, and wherever that conduit comes out of the ground and up a hot wall or through an attic, the wire gets derated for Arizona heat.
When you need it
- →A hot tub, RV pad, or well pump needs its own power
- →You're building a shop, casita, or detached garage on the lot
- →Breakers trip when the welder or compressor starts up
- →A tenant improvement needs a subpanel and dedicated circuits for new equipment
How we run it
Estimate visit
We walk the site, measure the run, read your main panel, and write a real number. The load calculation happens here, before anything is ordered.
Permit and run
We pull the electrical permit with your city, or with Maricopa County if you're outside city limits, and indoor circuits get fished straight back to the panel. A feeder to a detached building goes underground in conduit: we call Arizona 811 to get the public utility lines marked, then walk the route with you so you can flag any private lines past the meter, irrigation, a gas run to a grill, a feed to a shed, before we dig. The inspector checks the trench at depth before we backfill.
Land and inspect
Breakers set, the subpanel grounded and bonded the way a detached structure requires, GFCI and disconnects where code calls for them. The inspector signs off at final before you plug anything in.
Questions
One load, one circuit. A hot tub or an RV pedestal is a dedicated circuit. A building with lights, receptacles, and its own AC wants a subpanel, because code limits a detached building to one feeder, not a handful of separate circuits across the yard. We size the feeder for what the building will actually pull.
That's the load calculation. A panel can be out of breaker spaces with amperage to spare, and a subpanel fixes that. If the service is maxed, a subpanel just moves the problem. The honest fix is a service upgrade: bigger meter socket, main, and service wire, with APS or SRP pulling the meter. You see the math either way.
Four things. Its own grounding electrode, two ground rods or the rebar in a new slab, landed on the subpanel's ground bar. Neutrals separate from grounds, bonding screw pulled. A four wire feeder in PVC conduit with 18 inches of cover. A main breaker so the building shuts off in one spot. Skip one and the inspector fails it.
Ready to get it on the calendar?
Tell us about your circuit or subpanel job and a licensed electrician will come scope it and write you a real number.
Or call (443) 559-1598Veteran owned · ROC 338610 · 4.9 stars, 174+ reviews