Mission-critical work
Data Center and Mission-Critical Electrical
Capability, scope splits, and the Maricopa County rules that set the schedule on a critical-load job.
Mission-critical electrical is mostly a procurement and coordination problem wearing an engineering costume. The one-line is usually settled before we see it. What is still open is whether APS or SRP can deliver the capacity, when the gear can be released for manufacture, and whether the commissioning script can be run without buying a second outage. Read this as capability. We are not going to list data center projects we have not built.
Start with the utility, not the one-line
The constraint in this market is powered land, not demand. CBRE's H2 2025 read on Phoenix says APS and SRP power-delivery restrictions are limiting the availability of powered sites, and that SRP was working through its first cluster study of 25 applicants with mixed results. Capacity is the long pole.
Which utility serves the site is not readable off a ZIP code. SRP's own city list says its territory is served all or in part, and APS serves parts of Phoenix, Glendale, Peoria, Avondale and Scottsdale too. Downtown Mesa is a third answer: the city runs a municipal electric utility.
- APS extensions run under ACC tariff Service Schedule 3. The applicant signs a Line Extension Agreement and pays all project costs in advance. Anything unrefunded at five years becomes a non-refundable contribution in aid of construction, and none of it earns interest.
- SRP is not ACC rate-regulated, so none of that applies. Its contribution in aid of construction is generally non-refundable, and any extension over 1,000 feet is individually evaluated and agreed in writing.
- Redundant capacity is priced as such. Schedule 3 §9.4 lets APS add a capacity-factor component for applicants requesting excess or redundant capacity. A 2N request is not two N services at the same unit rate.
The field split is the same at both utilities and it lands on the electrical contractor. The customer trenches, installs conduit and provides the transformer pad; the utility sets the transformer, owns the meter and furnishes the CTs. SRP wants 12 feet of clear working space at the front of a pad-mount, and CLSM backfill per MAG Section 728.
Redundancy topology, and what it costs upstream
N+1, 2N, 2N+1, distributed redundancy, catcher blocks. The topology sets the count of nearly everything we install, and it sets it twice — once on the UPS side, once on the generator side. Before pricing we want the two questions under the label answered in writing: what can be taken out of service for maintenance without dropping load, and what can fail unannounced.
Density drives everything below the UPS: how many remote power panels, busway or whips, breaker frame sizes, how much copper ends up above the ceiling. Tell us whether the stated kW per cabinet is an average or a peak, and whether liquid cooling is in scope — CDUs arrive late and want their own distribution path.
Topology also meets a hard utility ceiling. SRP's sizing table caps a new three-phase four-wire underground service entrance section at 3,000 A, at 277/480 V and 120/208 V alike. Above that you are into multiple service sections, totalized metering at SRP's sole discretion, or primary-metered service — APS gives high-voltage metering its own ESRM section, 1000.
UPS, distribution, and the approval that gates the gear order
On the UPS side the work is the same whatever badge is on the module: input and output switchboards, the maintenance bypass and its interlocks, battery or flywheel room feeders and disconnects, and the control and alarm wiring nobody prices. Downstream it is PDUs, static transfer switches, remote power panels and branch distribution into the white space. We build to the owner's standard set, or take a stated topology through our design-build side.
The utility submittal sits in front of the manufacturing release, not after it. APS ESRM 302.9 requires every commercial meter enclosure to be reviewed and approved by APS before the equipment is manufactured. That is a gate on the gear order, and the gear order is the schedule.
The submittal carries manufacturer one-lines showing the neutral-to-ground bond link and neutral disconnecting means, EUSERC page references, ampacity, voltage, phase, bus bracing — the AIC rating — and the number of service disconnects. Every APS commercial service above 200 A needs a EUSERC-approved CT-rated meter enclosure. SRP's equivalent goes to shopdraw@srpnet.com, where its own document disagrees with itself: Section 1 says panels over 225 A, Section 9 says 400 A. We submit at 225 A.
One more line in that same ESRM paragraph earns its own sentence. A separate APS application is required whenever the service equipment includes any connection or provision for an inverter or generator. On a mission-critical job that is always true, so carry two APS reviews.
Commissioning, studies and the energization sequence
Phoenix amended the 2024 IECC so that compliance with Section C408 is optional, its justification being that commissioning happens after the certificate of occupancy is issued. That removes an energy-code line item. It has nothing to do with the owner's own commissioning program, which is contractual and is where the schedule risk lives.
A commissioning agent's plan normally runs a ladder: factory witness testing on gear and UPS modules, pre-functional checklists on site, functional performance testing device by device, then integrated systems testing where the utility source is dropped and the plant carries load through the transfer and the return. Our share is the unglamorous share — torque records, phase rotation, insulation-resistance testing, thermographic scans under load, and transfer timing witnessed rather than asserted.
- Short-circuit, coordination and arc-flash studies carry a lead time of their own, because they need final gear data rather than catalog data. See power studies.
- Generator testing becomes a utility event the moment the plant parallels. APS requires ten business days' notice before a generating facility begins interconnected operation or commissioning tests, and runs the ACC Article 26 tracks through PowerClerk with the Level 3 study track at 2 MW and above. SRP is not bound by those rules and classifies by the sum of every generator on site.
- Available fault current is a utility number and it moves. When APS or SRP rebuilds the feeder, equipment short-circuit ratings and the arc-flash study should be revisited, not left at the shop-drawing value.
What the desert and the code line do to the design
Phoenix's ASHRAE cooling design dry bulb runs around 110°F, and NEC 310.15(B)'s informational note names the ASHRAE Handbook—Fundamentals as the source, so the number is defensible rather than folklore. Through Table 310.15(B)(1) a 90°C conductor keeps 87 percent of its table ampacity in the 41–45°C band and 82 percent in the 46–50°C band. Where a raceway sits in direct sun less than 7/8 inch above a roof, 310.15(B)(2) adds 33°C on top — and XHHW-2 is exempt, a real money lever on long rooftop runs.
- NEMA 3R is the wrong outdoor default here. Type 3R is rainproof and carries no windblown-dust requirement at all; Type 4 and 4X do. Paralleling gear and radiator controls sit out through haboob season.
- PVC moves. NEC 352.44 wants an expansion fitting once calculated movement reaches 1/4 inch in a straight run, and practice adds 30°F to the high ambient for sunlit PVC. Duct bank runs cross that easily.
- EMT alone is not an equipment grounding conductor in Phoenix, Glendale or unincorporated Maricopa County. All three amend NEC 250.118(4) to require a wire-type EGC as well. Across a data hall that is a quantity, not a detail.
- Branch metering is an owner requirement here, not a code one. Phoenix deleted IECC C405.13 along with C405.12 and C405.15, so end-use metering has to be in the specification to be in the bid.
Which code year applies depends on the property line, not the metro. Phoenix has been on the 2023 NEC since 1 August 2025 under Ordinance G-7397; Mesa since 8 January 2026, Glendale since 9 January 2026. Unincorporated Maricopa County is still on the 2017 NEC and its energy code is voluntary. Arizona has no statewide building code.
Permits, phased turnover, and where we are a bad fit
Phoenix permitting runs through SHAPE PHX, which took on commercial plan review and inspections on 27 April 2026. From the city's July 2026 turnaround report: Major commercial averaged 30 days against a 45-day goal; Minor, under 5,000 square feet or $350,000, averaged 33 days against a 25-day goal. The small white-space permit is running slower than the shell.
| Item | Fee |
|---|---|
| Permit fee, valuation over $10,000,000 | $54,253 plus $5 per additional $1,000 |
| Commercial plan review over $50,000 valuation | 80% of the permit fee |
| Worked example, $25,000,000 valuation | $129,253 permit plus $103,402 plan review |
| Temporary or partial certificate of occupancy | $780 each; TCO valid 180 days, no renewals |
A temporary certificate of occupancy is how a first data hall goes live while the rest of the building is still under construction, and in Phoenix it runs 180 days with no renewals. A campus doing continuous fit-outs should look at the Annual Facilities Program, where the plan reviewers are also the inspectors.
Where we are the wrong call
- We are not an EPC for a greenfield hyperscale campus. If the package is a multi-hundred-megawatt build on a hyperscaler's schedule, you will hear that on the phone, not after the bid opening.
- Low-voltage and structured cabling are not on our license list. The fiber plant, the DCIM network and the security system ride with a specialty contractor; we install the pathway, the boxes, the grounding and the power to it.
- Factory startup of UPS modules and generators belongs to the manufacturer's field service. We land and terminate the feeders, set the interlocks, and stand there for it.
- We do not run a round-the-clock critical-facility response desk. Posted hours are Monday to Thursday, 6:00 AM to 3:00 PM, and Friday, 6:00 AM to 2:00 PM. Switchover work is scheduled and priced up front.
Where we do fit: service and distribution equipment, underground duct banks under our KA engineering license, the generator yard and its installation, gear setting and termination, the studies, and fit-out inside a running building. Our license classes are on the credentials page. Send the one-line and the utility correspondence and we will tell you what we should be bidding. Get in touch.
Frequently asked questions
Which utility will serve my data center site, APS or SRP?
You cannot tell from the city name or the ZIP code. SRP's own service list describes its cities as served all or in part, and APS serves portions of Phoenix, Glendale, Peoria, Avondale and Scottsdale as well. Downtown Mesa is a third case entirely, because the City of Mesa runs its own municipal electric utility across roughly 5.5 square miles and about 18,000 customers. The reliable methods are to read the utility name off an existing bill at the site, check the APS Phoenix Metro service territory map, request an SRP facility map, or call APS or SRP and ask. On an SRP job the design representative formally verifies that the property sits in SRP territory as part of the request-for-service process. The answer decides which standards manual, which portal, which submittal address and which cost rules apply, so it is worth settling before anything is priced.
How long does it take to get a new utility service for a data center in Phoenix?
Neither utility publishes a committed timeline and we will not invent one. The APS construction process page says only that project timelines vary by job complexity and current turnaround times, and nothing in the Electric Service Requirements Manual commits to a number of weeks. What we can describe is the sequence that consumes the time: application and load data, design, a line extension agreement with payment in advance, trench and conduit by the customer, utility inspection of trench and conduit before backfill, the equipment pad, an APS inspection of the service entrance equipment in addition to the AHJ inspection, then AHJ clearance, and only then energization by utility employees. CBRE has also reported that APS and SRP power-delivery restrictions are limiting the availability of powered sites in this market, so on a large load the capacity conversation can precede all of that. Start it before the design is finished, not after.
Does Phoenix require commissioning on a data center?
Not through the energy code. Phoenix amended the 2024 IECC so that compliance with Section C408 is optional, with the city's justification being that commissioning takes place after the certificate of occupancy is issued. That is a real difference from a jurisdiction that adopted the 2024 IECC unamended, and it changes what a bid has to carry. It has no bearing at all on the owner's own commissioning program, which is a contract requirement rather than a code requirement and which is normally far more demanding than anything the energy code would have asked for. If a commissioning plan is in the documents, assume it is in the scope and price the labor to support it, including integrated systems testing.
What edition of the NEC applies to my project?
It depends on which side of a property line the project sits, because Arizona has no statewide building or electrical code. Cities and counties adopt and amend independently under A.R.S. Title 9 and A.R.S. 11-861. Phoenix has enforced the 2023 NEC since 1 August 2025 under Ordinance G-7397. Mesa moved to the 2023 NEC on 8 January 2026, Glendale on 9 January 2026, and Chandler applies it to plans submitted on or after 1 July 2025. Scottsdale is on the 2020 NEC. Unincorporated Maricopa County is still on the 2017 NEC, and the county's energy code is voluntary rather than mandatory. Several Valley cities could not be confirmed from primary sources in our research, so for those we call the building department before design rather than guess. A campus on county land and a campus one street inside a city boundary can genuinely be two different designs.
Can you take on a hyperscale campus?
No, and it is better for both of us to say so early. A multi-hundred-megawatt greenfield build running on a hyperscaler's schedule with a national program manager needs a contractor built for that, and we are not going to bid it in order to find out. Where we are a sensible fit is the infrastructure around and under the critical load on projects sized to us: the service and distribution equipment, the duct banks and site work, the generator yard, gear setting and termination, the studies, and fit-out and expansion work inside a building that is already running. Enterprise and edge facilities, colocation suites, and the mission-critical rooms inside hospitals, manufacturing plants and municipal buildings are where our scope lines up.
Do you design the redundancy topology, or only install it?
Either, with one condition. If the owner has a design standard and a stamped set, we build to it and our value is in the installation, the coordination and the commissioning support. If the project is design-build, we will develop the distribution to a topology and a commissioning requirement that you state, working through our engineering side. What we will not do is pick N+1 or 2N on your behalf from a load number, because that is a business decision about downtime and about how much redundant capacity you are willing to buy from the utility. APS Service Schedule 3 specifically allows a capacity-factor component to be added for applicants requesting excess or redundant capacity, so the topology decision reaches all the way back into the line extension cost.
What is usually the longest-lead item on a mission-critical electrical package?
The service and distribution gear, and the reason is not only the factory. APS requires every commercial meter enclosure to be submitted for its review and approval before the equipment is manufactured, and that submittal has to include the manufacturer one-lines, the EUSERC page references, the ampacity, the bus bracing or AIC rating, the number of service disconnects and the street address. A separate APS application is required on top of that whenever the equipment includes any connection or provision for a generator or inverter, which on a mission-critical job it always does. SRP runs a parallel shop drawing review through its Distribution Design group. So utility review sits in front of the manufacturing release, and a topology change after that point restarts a queue you do not control. Lock the one-line before the gear is released.
Get a price on this scope
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Send us the plans, the scope, or just the problem. We will tell you what it takes. Call (602) 396-5216 or request a bid online.