Mission Critical

Mission-critical power is measured in seconds.

Generators, transfer switches, emergency lighting and the distribution behind them, for facilities that can’t go dark. Excel supplies contractors and facility teams across Metro Detroit from our Warren and Waterford Township branches.

Start a project quote Watch an outage play out

Emergency systems back on

Within 10 seconds.

10 s: Emergency systems, NEC 700.12
60 s: Legally required standby, NEC 701.12

What happens when the utility drops.

Press play, or step through each moment to see what the equipment is doing and what we supply for it.

Site statusT + 0 s

Utility Lost
UPS On battery, no break
Generator Start signal, cranking
Transfer switches Normal position
Emergency loads Waiting for transfer
Legally required standby Waiting
Optional standby Off

0 s

The utility drops.

Power from the utility is gone. Loads on a UPS keep running from its batteries without a break, and the transfer switches signal the generator to start.

What we supply here

Surge protective devices
Battery & backup components
Disconnects

Site statusT + ≤ 10 s

Utility Lost
UPS On battery
Generator Running
Transfer switches Emergency transferred
Emergency loads Restored
Legally required standby Waiting
Optional standby Off

≤ 10 s

Emergency systems come back.

The NEC gives emergency systems 10 seconds. The generator comes up to speed and the emergency transfer switch picks up egress lighting, fire alarm and other life safety loads.

What we supply here

Automatic transfer switches
Commercial standby generators
Emergency lights & exit signs

Site statusT + ≤ 60 s

Utility Lost
UPS On generator, recharging
Generator Running
Transfer switches Emergency & standby transferred
Emergency loads On
Legally required standby Restored
Optional standby Waiting

≤ 60 s

Legally required standby follows.

Loads required by code or the authority having jurisdiction, such as some ventilation, smoke removal and communications systems, must be back within 60 seconds.

What we supply here

Automatic transfer switches
Panelboards
Circuit breakers

Site statusT + + Optional

Utility Lost
UPS On generator
Generator Running
Transfer switches All transferred
Emergency loads On
Legally required standby On
Optional standby On, as capacity allows

+ Optional

Optional loads, as capacity allows.

Optional standby loads that protect the operation come back next, often through load-shed controls so the generator isn’t overloaded.

What we supply here

Panelboards
Lighting & load contactors
Circuit breakers

Site statusT + Hours

Utility Lost
UPS Charged, standing by
Generator Running, fuel monitored
Transfer switches All transferred
Emergency loads On
Legally required standby On
Optional standby On

Hours

Riding it out.

The site runs on the generator for as long as the fuel and the design allow, while the UPS stays charged and ready for the next transfer.

What we supply here

Generator accessories
Wire & cable
Grounding & bonding

Site statusT + Utility back

Utility Restored, stabilizing
UPS Normal
Generator Cool-down run
Transfer switches Retransfer after time delay
Emergency loads On
Legally required standby On
Optional standby On

Utility back

Back to normal, on a delay.

Once the utility is stable, the transfer switches return to normal after an adjustable time delay, and the generator runs a cool-down cycle before it stops.

What we supply here

Automatic transfer switches
Metering equipment
Control cable

Example sequence for illustration. Timing and load assignments come from your engineer’s design and the NEC.

Redundancy, explained.

Mission-critical designs add capacity so one failure doesn’t take the site down. Here’s what the shorthand on your drawings means.

N

Exactly the capacity the load needs. If one unit is down, the load isn’t fully covered.
N+1

One extra unit, so any single unit can fail or be down for service without dropping the load.
2N

Two complete, independent systems, each able to carry the full load on its own.

Standby generator enclosure beside a switchgear lineup in an electrical room

Keep the critical spares on the shelf.

When a part fails at 2 AM, the spare in your stockroom beats any delivery. Send your list and we’ll quote it.

Fuses for critical circuits
Breakers for key panels
Contactors & control relays
Generator starting batteries
Emergency lighting batteries
Surge protective devices
Pilot lights & indicators
Control fuses & fuse blocks

Send your spares list

Mission-critical facilities we supply

911 & dispatch centers
Emergency operations centers
Data centers
Hospitals
Telecom & network sites
Water & wastewater
Labs & research
Control rooms & financial operations

Mission-critical supply questions

What’s the difference between emergency, legally required and optional standby?

In the NEC, emergency systems (Article 700) serve life safety loads and must be restored within 10 seconds. Legally required standby systems (Article 701) serve loads required by code or the authority having jurisdiction, such as some ventilation, smoke removal and communications, within 60 seconds. Optional standby systems (Article 702) protect property and operations. Your engineer decides which loads go on which system.

Do you supply generators and transfer switches?

Yes. Send the kW rating, fuel type, voltage and phase, plus the transfer switch amperage, poles, transition type and whether it’s service-entrance rated, and we’ll quote the generator, ATS and accessories to your spec.

Can you quote a critical spares list?

Yes. Upload your list of part numbers or nameplate photos, and we’ll quote the fuses, breakers, contactors, batteries and other spares you want on the shelf.

Do you supply UPS systems?

We supply the breakers, disconnects, cable and battery components around UPS installations. Ask about UPS equipment for your project and we’ll let you know what we can quote.

Do you provide installation, testing or maintenance?

No. Excel is an electrical supply house. Installation, testing and maintenance of emergency and standby systems are handled by your contractor or service provider.

Working on a data center or hospital?

See our Data Centers and Healthcare Facilities pages for those projects.

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Plans & drawings
Material lists & takeoffs
Specs & cut sheets
Any other project type

Get a quote for your project.

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Warren, MI

Waterford Township, MI

Sterling Heights, MI

Mission-critical power is measured in seconds.

The utility drops.

Emergency systems come back.

Legally required standby follows.

Optional loads, as capacity allows.

Riding it out.

Back to normal, on a delay.

N

N+1

2N

Keep the critical spares on the shelf.

Mission-critical supply questions

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Tell us about your project

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