400-A 3-Phase Service Upgrade
Budget: $1,500 – $3,000 USD
I need a complete, engineer-stamped plan set that will take my commercial site in Blythe (Riverside County, CA 92225) from its existing 200 A, 120/240 V, 3-phase service to a 400 A, 120/208 V, 3-phase service. The Square D Speed E-Board meter stack has already been purchased and will be the heart of the new gear, so the drawings must integrate that exact equipment.
Because the county enforces its own amendments to the California Electrical Code, every detail—load calculations, conductor sizing, AIC ratings, grounding, and fault-current study—has to reference Riverside County requirements in addition to Title 24 and the latest NEC. The sole driver is additional capacity for new production equipment due later this year, so headroom for future expansion is not a factor; an accurately sized, code-compliant design that will pass plan check the first time is.
Deliverables I expect:
• Signed and sealed single-line diagram showing the new 400 A service, CT cabinet (if required), Speed E-Board configuration, main disconnect, feeder runs, OCPDs, and terminations.
• Panel schedules with calculated demand loads.
• Conduit, conductor, and grounding details keyed to local temperature and derating tables.
• Short-circuit and voltage-drop verification.
• Any notes, load letters, or compliance forms Riverside County typically asks for at submission.
PDF format is fine for review; a final CAD (DWG) copy will also be needed for my records.
If you’ve recently engineered similar 400 A 3-phase upgrades within Riverside or neighboring counties and have a stamp recognized here in California, I’d like to see a quick sample of your work or a permit number I can reference. I can provide utility service rules, existing panel photos, and the Speed E-Board cut-sheets as soon as we begin.
Because the county enforces its own amendments to the California Electrical Code, every detail—load calculations, conductor sizing, AIC ratings, grounding, and fault-current study—has to reference Riverside County requirements in addition to Title 24 and the latest NEC. The sole driver is additional capacity for new production equipment due later this year, so headroom for future expansion is not a factor; an accurately sized, code-compliant design that will pass plan check the first time is.
Deliverables I expect:
• Signed and sealed single-line diagram showing the new 400 A service, CT cabinet (if required), Speed E-Board configuration, main disconnect, feeder runs, OCPDs, and terminations.
• Panel schedules with calculated demand loads.
• Conduit, conductor, and grounding details keyed to local temperature and derating tables.
• Short-circuit and voltage-drop verification.
• Any notes, load letters, or compliance forms Riverside County typically asks for at submission.
PDF format is fine for review; a final CAD (DWG) copy will also be needed for my records.
If you’ve recently engineered similar 400 A 3-phase upgrades within Riverside or neighboring counties and have a stamp recognized here in California, I’d like to see a quick sample of your work or a permit number I can reference. I can provide utility service rules, existing panel photos, and the Speed E-Board cut-sheets as soon as we begin.