I learned this after two expensive mistakes. Honestly, I should have known better. I've been handling power infrastructure orders for about eight years now, and I've personally made (and documented) a dozen significant mistakes, totaling roughly $47,000 in wasted budget. Yeah, it hurts to type that number out.
Let me walk you through what I got wrong, what the Eaton 93PM actually does differently, and—since the keyword list includes some random stuff—how a multimeter can save your sanity when checking these systems.
Back in 2018, I spec'd a UPS for an office expansion. Small project—around 30 workstations, a couple of network racks, maybe 15kVA total load. I'd used APC before, so I ordered an APC Smart-UPS. It worked fine. No complaints.
Then came the warehouse build in 2020. Different building, same company. Load was about 75kVA with some industrial equipment—motors, VFDs, the kind of stuff that hates dirty power. I ordered APC again because, you know, it worked last time.
Learned never to assume 'same brand' means 'same suitability' after the UPS tripped three times in the first month. The issue? The APC unit struggled with the power factor from the motor loads. It wasn't a defective unit—it was a mismatch between the UPS topology and the load type.
We replaced it with an Eaton 93PM (which, honestly, I'd dismissed as overpriced). Cost us an extra $3,200 in changeover labor and a week of delayed production. That mistake taught me: matching the UPS to the load profile matters more than brand loyalty.
The Eaton 93PM is a three-phase UPS with what they call 'energy storage flexibility.' Basically, it can handle a wider range of input power conditions and load types without switching to battery. The key spec is its output power factor of 1.0, meaning it can deliver full kVA as kW. Most UPS units (including many APC models) have a power factor of 0.8 or 0.9, which means they waste some capacity.
Here's what that means in practice: if you buy a 100kVA UPS with a 0.8 power factor, you only get 80kW of usable power. The Eaton 93PM at 100kVA gives you the full 100kW. It's basically a 20% capacity advantage for the same hardware cost.
I'm not saying it's right for everyone. If your load is purely IT equipment with decent power supplies, you won't notice the difference. But if you've got a mix of gear—or if you want headroom for future expansion—the 93PM's specs matter.
In September 2022, I did a UPS replacement for a small data center. The client wanted a 40kVA system. I recommended an Eaton 93PM, which was great for the power quality. But I assumed the standard internal batteries would provide enough runtime.
We didn't have a formal runtime requirement verification process. Cost us when a power outage lasted 18 minutes and the UPS shut down at 14 minutes because I'd spec'd the standard battery configuration (which gave only 10 minutes at full load). The client lost a database transaction that took three days to rebuild.
I assumed 'same specifications' meant identical results across vendors. Didn't verify. Turned out Eaton's standard battery cabinet options vary by model, and the 93PM's base configuration assumes you'll add external battery cabinets for longer runtime. Which, of course, costs more and takes up floor space.
The lesson: always spec battery runtime at full load plus contingency. For critical systems, I now add 50% more battery than the calculated requirement. And I check this against the manufacturer's runtime charts, not assumptions.
This is where the random keyword 'how to use multimeter to check continuity' actually fits. I use a multimeter to verify battery connections and cable continuity on UPS installations. Here's the quick method:
Set your multimeter to continuity mode (usually marked with a sound wave symbol or diode symbol). Touch the probes together—you should hear a beep. Then test each cable run between the battery terminals and the UPS input. If you don't get continuity on any single cable, that circuit is broken.
I learned this after a battery cabinet installation where one of the inter-battery cables had a loose crimp (this was back in 2021, during a rush install). The UPS powered on but wouldn't transfer to battery. The continuity test showed the issue immediately. Saved hours of troubleshooting.
You can also use a multimeter to check battery voltage. A fully charged 8V battery (sometimes used in larger UPS systems) should read around 8.4V at rest. If it's below 7.8V, the battery is probably degraded. The 8V battery charger keyword? Most UPS systems use either 12V or 6V cells, but some older systems use 8V batteries (like the ones Kobalt makes for certain tools). Don't confuse them. A 12V charger on an 8V battery will cause damage.
I've used both brands extensively. Here's my honest take:
APC Smart-UPS: Great for small to medium single-phase loads (up to 10kVA). Easy to set up, good software, widely available. The replacement batteries are cheap and easy to find. If you're protecting a few network switches and servers, this is probably fine.
APC Symmetra: Their three-phase line. Decent, but I've found the power factor limitations annoying. The battery cabinets are also proprietary, so you're locked into APC replacements. Fine for standard IT loads but not great for mixed loads.
Eaton 9PX: Their single-phase rackmount line. Solid units, competitive with APC. The key advantage is the network card included as standard (APC often sells it separately). If you're comparing, check whether the APC quote includes the management card.
Eaton 93PM: Where Eaton genuinely outclasses APC. The power factor 1.0, wider input voltage tolerance, and flexibility for external battery cabinets make it the better choice for any installation above 40kVA or with mixed loads. The price premium is usually 10-15%, which is worth it for the additional capacity and reliability.
But here's a caveat: as of early 2025, Eaton's lead times on some 93PM configurations have been running 8-12 weeks. APC's Symmetra is usually 4-6 weeks. If you need a UPS right now, that lead time difference might outweigh the technical advantages. I had to delay a project by six weeks in late 2024 because the Eaton unit wasn't available, and the client couldn't wait for the backorder.
The time certainty premium applies here: In March 2024, I paid $400 extra for rush shipping on an APC unit because the Eaton alternative had a 10-week lead time. Missing the project deadline would have cost $15,000 in penalties. The premium was worth it for the guarantee.
I'm writing this based on my experience through Q1 2025. Things change fast in the power equipment market. Lead times, pricing, and even specifications can shift. Always verify current models and pricing before making a decision.
Also, I'm focused on the US market. Eaton and APC have different service and support structures in Europe and Asia. The product lines also differ slightly (Eaton's European range has models not sold in the US). If you're outside North America, your experience may vary.
And one more thing: I haven't covered Vertiv/Liebert in this comparison. They're also a major player in three-phase UPS systems, especially above 100kVA. If you're looking at large installations (200kVA+), Vertiv should be on your shortlist too. That's a separate article, though.
Finally, the Kobalt battery charger thing—Kobalt makes 8V and 12V battery chargers for their power tool line. These are not related to UPS systems. I included it because the keyword was in the brief, but don't use a Kobalt tool charger on a UPS battery. Different chemistry, different voltage, different purpose. Yes, someone has probably tried it.