Eaton Power Gear FAQ: UPS Sizing, 30A Disconnects, PGE EV Rebates, and Surge Protection

I'm an electrical engineer who's spent the last seven years specifying and installing backup power, UPS systems, and solar-connected equipment for commercial buildings. I've made enough expensive mistakes that my team now has a checklist. This FAQ is the list I wish someone had handed me before I burned budget on the wrong gear.

The questions below are the ones customers and junior engineers actually ask. If you're deciding between an Eaton 93PM UPS, a 30 amp disconnect, a battery backup system, or a surge protector, start here.

• What size Eaton 93PM UPS do I actually need?
• What does an Eaton 30 amp disconnect do?
• Does Portland General Electric offer an EV charger rebate?
• Is a solar generator with battery a real backup system?
• Is surge protector necessary if I already have a UPS?
• Is Eaton worth the premium over generic power gear?

What size Eaton 93PM UPS do I actually need?

Take the nameplate load, not the estimated IT load. I learned this in 2018, when I specified a 30 kW Eaton 93PM UPS for a small colocation closet because 'nothing here draws that much.' Three months later, a new compute node pushed the load over the rated output. The alarm caught it before failure, but it cost us a weekend and a lot of embarrassment.

According to Eaton's 93PM spec sheet (eaton.com/93pm), this family covers 20 kW to 100 kW and uses online double-conversion topology. That means the inverter is running continuously, so the load matters every minute. I should add: oversizing is also a mistake. A UPS loafing at 10% load is inefficient and can create battery stress over time. A UPS running above 80% leaves no headroom for inrush or future IT loads. The sweet spot is between 40% and 80%.

Rule I use now: never trust a circuit schedule by itself; verify the nameplates and, if possible, measure actual load with a meter.

Don't guess. Have a load study done by an electrical contractor who understands three-phase systems. The cost of the study is less than the cost of a wrong 93PM order.

What does an Eaton 30 amp disconnect do?

A 30 amp disconnect is a visible, lockable switch between the power source and the equipment. In a solar or battery install, the inspector wants to see a disconnecting means so a service technician can kill the circuit before touching anything. The National Electrical Code calls this out for PV systems in Article 690.15.

The '30 amp' rating is not a recommendation. It's a cap. I once used a 30A disconnect on an inverter output that had a 40A breaker at the source. The contacts welded on a startup surge. That was a $3,200 mistake and a three-day delay.

Eaton makes several 30A disconnects: fused, unfused, with or without a neutral kit, and in metal or non-metallic enclosures. The one you need depends on the circuit type, the voltage, and whether it has a grounded conductor. For an air conditioning unit, a simple pull-out disconnect is usually enough. For a PV or storage circuit, you may need a lockable safety switch with visible blades. Ask your electrical supplier before you assume the cheapest one works.

Does Portland General Electric offer an EV charger rebate?

Short answer: yes, as far as I can tell. I checked Portland General Electric's EV page before writing this, and as of April 2025 they're still running charging incentives for Oregon customers. But the details keep moving. In one earlier program cycle, the rebate for a qualified Level 2 home charger was around $500. Then the program paused, then it came back with different terms. Don't hold me to that number; verify it on their official EV page.

Here's the mistake I keep running into: people order a charger before checking the approved equipment list. In 2023, a customer bought one that wasn't on PGE's list. Installed, it was a $1,300 job, and the rebate was zero. I'll say it plainly: if you're looking for the Portland General Electric EV charger rebate, the current official source is portlandgeneral.com/ev, not a local installer's blog.

If you're a business, ask about the commercial charging program too. It's a different application, and the requirements for site hosts are more involved. (Should mention: the residential rebate may also require a licensed electrician and a permit. Factor that into your savings.)

Is a solar generator with battery a real backup system?

Depends on what you mean by 'solar generator.' It's not a generator in the gas-engine sense. It's a battery bank, an inverter, and a solar charge controller in one portable box. To be fair, if you need power on a job site, at an event, or in a rental office, a solar generator with battery is great. It'll run lights, a laptop, and a router.

But it is not a whole-building backup. I've watched people assume that because the inverter is rated 3,000 watts, they can do the same things they did with a 3,000-watt gas generator. What they don't see is startup surge. A refrigerator or a well pump can draw three to five times its running watts for a few milliseconds. If the inverter can't handle that inrush, it trips, and you're back in the dark.

If you already own a solar generator with battery, put it on a dedicated load group—lights, comms, and a few receptacles. That's honest about its limits. If you want permanent battery backup with solar input, that's an energy storage system, not a portable generator. That's a different product family, and it's one you should spec with a licensed contractor.

Is surge protector necessary if I already have a UPS?

Yes, and here's why: a UPS and a surge protector do different jobs. The Eaton 93PM has built-in surge suppression on its output, but that's not a whole-building lightning defense. Put another way: a UPS handles blackouts and voltage dips; a surge protector handles spikes.

A whole-house or panel-level surge protector is the first line of defense. The cheap power strip with 'surge protection' is not enough, and I don't say that to sell a more expensive part. I say it because I've watched a $180 panel protector save $4,800 worth of VFDs. In 2022, a customer asked me the exact question—is surge protector necessary?—after lightning hit their block. The quote to replace two variable frequency drives was $4,800. They'd declined the panel protector six months earlier because it seemed optional. Now they have one.

There's a technical angle too. Surge protective devices are tested to UL 1449, and their failure mode matters. A good unit tells you when it's done protecting. A cheap one just sits there, and you may never know. So yes, it's necessary—in addition to a UPS, not instead of one.

Is Eaton worth the premium?

For the kind of work I do, yes. Eaton is not the cheapest option, and if you're putting a basic 30 amp disconnect in a dry closet, a generic one might work fine. But I stopped buying generic for customer-facing installs because my callback rate dropped after I standardized on Eaton gear.

I won't trash competitors—that's not a fair way to make a recommendation. What I can tell you is that the details matter: torque markings that are actually readable, accessories that fit without filing, and documentation that doesn't vanish when the model is revised. From the outside, a $30 disconnect and an Eaton 30 amp disconnect look identical. The reality is the cheap one often becomes the next electrician's frustration. Your client sees what's in the panel too. They may not say 'nice torque specs,' but they notice a clean, professional-looking install. That impression is part of the job, and quality is part of your brand.

I can only speak to commercial installations. If you're a homeowner doing a small project, the calculus might be different. But even there, I'd put the money on the disconnecting means and surge protection first. Those are the two places where a failed part can create a safety issue, not just an inconvenience.