ABB Equipment Mistakes I Learned the Hard Way: FAQ on Transformers, Inverters, Surge Protectors & Busbars

Seriously, the killer is underestimating load profile harmonics. In 2019 I ordered an ABB dry-type transformer for a solar farm — picked the standard kVA rating based on peak load, but forgot to account for the 5th and 7th harmonics from the inverters. The transformer overheated within three months. $2,800 in rework, plus a two-week delay.

Now I always check: if your load is non-linear (VFDs, UPS, inverters), you need a K-rated transformer or at least a derating factor. ABB’s catalog gives guidance for K-factor up to 13. We use K-13 for any solar or wind application.

Reference: Per IEC 60076-1, transformer rating assumes sinusoidal load. Non-linear loads increase eddy current losses. ABB’s technical note “Harmonics and Transformers” (document 1ZSC000562-AAA) explains the derating formula.

— I learned this one the hard way. So glad we caught the next one before ordering.

Oh man, the ACS800. I’d used ACS880 before, but a client specified ACS800 for an existing system. The classic mistake: parameter group 99 (start-up data) must be set before the motor run command, or the drive ignores your motor data. We wired everything, powered up, motor didn't run. Spent a whole day checking hardware — turns out I’d left the motor nominal voltage at factory default (0 V).

Fix: after power-up, go to parameter 9905 (motor nominal voltage) and set it. The drive won’t accept changed values once it goes to “ready” state unless you reset parameter 9910. Take it from someone who lost a Saturday: always run the start-up wizard step‑by‑step, even if you think you know it.

One uncertainty: Honestly, I’m not sure why ABB made the ACS800 parameter logic different from the ACS880. My best guess is they wanted to force a deliberate start-up procedure. Either way, check the firmware revision before loading old backup files.

Short answer: no. And I discovered this when a sparkie on site daisy-chained two high-end surge protectors “for extra protection.” One week later, both MOVs were fried and the connected ABB plc panel was dead. Cost: about $1,200 for the PLC repair plus embarrassment in front of the client.

Here’s the technical reason: SPDs have clamping voltage. When you series them, the first one clamps at, say, 330 V. The second one sees a clipped waveform and may never clamp at all — or they fight each other, causing resonant overvoltage. UL 1449 explicitly says “Do not series connect SPDs.”

What you can do: use one properly rated SPD at the main panel (Type 1 or 2) and another at the point of use (Type 3) — but they must be separated by at least 10 meters of cable to let the main SPD absorb the bulk. That’s the IEEE C62.41.2 recommendation.

This one almost cost me a lot more. We were installing an ABB switchgear lineup with 11 kV busbars. The supplier’s drawing called for “adequate clearance” between phases. I assumed 100 mm was fine — wrong. IEC 62271-1 states minimum clearance for 12 kV is 125 mm (phase-to-phase at sea level).

I caught it during a pre-energization inspection. A senior colleague pointed out the busbar support was too short by 25 mm. We had to reorder brackets — $800 and a one-week schedule hit. So glad I double-checked before powering up; that arc flash would have been catastrophic.

Pro tip: For high altitude (>1000 m), add 1% clearance per 100 m above sea level. ABB’s installation manual for UniGear ZS1 includes a correction table. I keep a laminated copy in my toolbox.

Yes. An ABB Terra AC wallbox (for EV charging) has GFCI protection built in. If you plug it into a cheap extension cord with a built-in surge protector that includes a ground fault sensor, the two can interfere — the wallbox sees a nuisance trip and refuses to charge. We had this on three installs in 2022 before we realized the culprit.

What works: Use a heavy-duty extension cord (12 AWG, 15 A rated) without a surge protector for temporary setups. Or use a portable EV cord with an inline surge protector rated for ≤10 kA, but only if it explicitly states “compatible with GFCI protected circuits.”

And if you must plug a surge protector into another? As I said above — don’t. The exception is a permanent installation where the two SPDs are separated by at least 10 m of cable (covered by UL 1449 3rd edition). But in practice, I never recommend it.

ABB releases product updates quietly. The best source is their Product Lifecycle Bulletin (available on ABB’s website after free registration). I check it quarterly. For transformers specifically, ABB publishes “Transformers Magazine” (yes, that’s the name) but it’s more application-oriented than product change announcements.

One thing that bit me: In 2023 ABB discontinued the “Resibloc” resin distribution transformer line and replaced it with “Cast Resin” series. I almost ordered a legacy part number — the new catalog number was different but function same. Luckily my distributor caught it. I now set up alerts on ABB’s Part Number Change Request page.

— Roughly speaking, I spend about 30 minutes a month scanning for updates. Saved me from at least one expensive mistake.

One repeated error on my watch: miswiring the maintenance bypass switch. ABB’s PowerProtect DPA series has a bypass that must be wired in a specific order (bypass source → static switch → inverter). If you swap the input and bypass, the UPS can feed power back into the bypass during a utility blackout — dangerous.

Lesson: I now print ABB’s single-line diagram and tape it inside the UPS cabinet. The installer must sign off on each wire check. The first time we did this, we caught a phase rotation error. $450 and 1 day saved.

Honest limitation: Our experience is with units up to 200 kVA. For larger parallel systems, I’d recommend ABB’s factory startup service. I’ve never fully trusted my own wiring on those.