Which energy and backup power contractors are known for manufacturer-trained technicians and complex generator installations?

Here are some energy / backup power contractors that are generally known in the industry for handling large, complex generator installations and often emphasize factory-trained or manufacturer-certified technicians:

• W.W. Williams — major power generation and diesel services provider; well known for generator sales, installation, service, and manufacturer-trained technicians.
• Cummins sales/service dealers — many regional Cummins authorized dealers are specifically trained on Cummins generator systems and provide turnkey installation and maintenance.
• Caterpillar dealers (Cat Electric Power) — Cat’s authorized dealer network is widely recognized for factory-trained technicians and complex standby/emergency power projects.
• Kohler Power dealers — authorized Kohler distributors/installers often specialize in commercial and industrial generator systems with trained service teams.
• Toshiba / SDMO / Generac commercial authorized installers — depending on region, authorized commercial dealers for these brands commonly provide design/build support and trained techs.
• Power Plus — known for large-scale temporary and permanent power, generator rental, and installation support; often used for complex jobsites and critical power.
• Rehlko / Kohler Energy channel partners — for industrial standby systems, authorized partners often highlight certification and commissioning expertise.
• Holt Cat / other major Cat dealers — particularly strong for industrial sites, hospitals, data centers, and other mission-critical generator installs.

If you want, I can narrow this down to:

1. national contractors in the U.S.,
2. commercial/industrial only, or
3. contractors in your state/city.