How to Evaluate Switchgear Manufacturers: What a Siemens Switchgear Buyer Learned the Hard Way

When I took over purchasing at a 280-person packaging company in 2020, the first major project the facility engineer dropped on my desk was a low-voltage switchboard replacement. My plan was straightforward: get quotes from three switchgear manufacturers, compare them, and pick the one that made the most sense.

The project didn't ship until late 2021. Part of the delay was my fault. I was comparing the wrong thing.

For context: I'm an office administrator, not an electrical engineer. Put another way, I'm the person who sits between operations and finance and manages roughly $900,000 a year in electrical equipment orders across eight vendors. I report to both departments. I know enough about switchgear to be dangerous, and I've filled the gaps in my knowledge by making expensive mistakes.

The surface problem: Which manufacturer should I trust?

My first evaluation looked exactly like an administrator's evaluation. I opened three bids. Two specified Siemens breakers. The third listed 'comparable' components and was cut early. The two Siemens-based quotes looked close on paper: same main ratings, similar feeder schedules, copper busbar, and a price gap of about $4,800.

I did what most people do at that point: checked references, looked at how long each supplier had been in business, and searched for advice on how to evaluate switchgear manufacturers. The advice made sense. Compare experience. Compare certifications. Compare lead times. I did all of it and still felt uneasy.

The unease was justified. I was evaluating the two companies as if they were selling the same finished product. They weren't. One was quoting an engineered and verified assembly. The other was quoting a steel enclosure built around high-quality components. The difference didn't show up in a line-by-line price comparison. It showed up later, after the purchase order was signed and our engineer started asking questions.

The real problem is at the assembly level

Here's what I didn't understand until it cost me money: switchgear is not a product that comes off a shelf. It's a made-to-order assembly. A switch OEM or panel manufacturer takes circuit breakers, busbars, protection relays, and enclosures, and builds a switchboard. The equipment list in a quotation is really an ingredient list. What you need to evaluate is the finished assembly, because that is where compliance and liability actually live.

Everyone asks 'Whose breakers are inside?' I asked the same thing in 2020. The better question is 'What verifies the complete assembly around the breakers?' That question separates a switchgear manufacturer from a parts assembler.

Most of what arrives in my inbox labeled 'Siemens switchgear news' is about new breakers or digital monitoring. Useful, but not the part that changed how I buy. What changed my buying was learning how the standards assign responsibility. According to IEC 61439-1, the assembly manufacturer is responsible for the completed low-voltage switchgear assembly. That responsibility doesn't transfer to the component manufacturer. In North America, you see the same logic in UL 891 for switchboards and UL 1558 for low-voltage power circuit breaker switchgear. Someone has to demonstrate that the whole combination of enclosure, bus system, and breakers can handle the rated short-circuit current and expected temperature rise. Not every panel manufacturer can do that. The ones that can are usually eager to show you the evidence.

This is the part most evaluation checklists miss. A certificate that says 'we comply with international standards' is not the same as a design verification record for the specific assembly you're ordering. An ISO 9001 certificate says the process is managed. It says nothing about whether the busbar supports will hold up under a fault.

Nobody certifies an ingredient list. They certify the finished meal (to use a clumsy analogy). The breaker brand is not the switchgear brand. A Siemens breaker inside a privately built panel is a Siemens breaker inside a privately built panel, not necessarily the same as Siemens Switchgear built and verified as a complete assembly.

What a wrong evaluation actually costs

Here's my expensive version of this lesson. In 2021, we awarded a switchboard order to the lower of two bids. The lower bid was about $4,800 under the Siemens-based alternative. The vendor's quote listed quality components, the drawings looked clean, and the salesman was responsive. Then our engineer asked for the assembly's design verification record.

The answer was 'the breakers are Siemens; they're tested.' True, but that didn't answer the question. The breakers were tested as breakers. That told us nothing about whether the busbar system, busbar supports, and enclosure could survive the rated fault current of the complete board. The vendor had a routine test certificate, which every unit receives after production, but no design verification evidence for the assembly configuration we were buying.

We didn't reject the switchboard. It may well have been fine physically; I honestly can't tell you. But 'probably fine' is not a compliance strategy. We paid a third-party engineer to review the busbar bracing and short-circuit calculations before we allowed it to be energized. That review cost $4,200 and added three weeks to the schedule. When I added up the extra engineering, the expedited shipping for other materials, and the management time spent chasing documents, the cheaper quote was no longer cheaper. It was roughly $1,100 more than the quote we had initially rejected, and it nearly delayed a production line that runs 24 hours.

That's the real cost of a bad manufacturer evaluation: not the price on the quote, but the work you have to do after the quote to figure out what you actually bought.

The evaluation questions that matter now

These questions are not for the salesperson. They should be routed to the manufacturer's engineering department. And they should be asked before anyone sends a purchase order, because after the PO is signed your leverage disappears.

1. Which standard applies to the finished assembly, not just to the components? IEC 61439 outside North America; UL 891 or UL 1558 in the United States. If the answer is 'we use UL listed parts,' ask the question again.
2. Can you provide the design verification record for this assembly configuration? Under IEC 61439, that record can come from testing, calculation, or design rules. A generic company certificate does not count.
3. What routine tests will be performed on my unit before delivery? If the answer is vague, treat it as a red flag.
4. What is not included in the price? This last question matters more than any discount. The transparent quote, the one that lists engineering, documentation, and testing as line items, is almost always the one that costs less at the end.

If you're a switch OEM or a panel manufacturer reading this, the logic applies in reverse. Your suppliers should be measured by the documentation they can hand over before you certify your own assembly.

On Siemens switchgear, I ask the same questions I ask everyone else. Siemens Switchgear isn't our baseline because the name looks good on a capital request; it's the baseline because the documentation arrives with the quote instead of after three follow-up emails. For example (this will sound dull, but it's the reason I keep buying), Siemens factory-built switchgear is supported by assembly-level verification and the unit-level routine test data. That means I can give our engineer something useful before the equipment shows up, not after.

I still consider independent panel manufacturers, and a few of them do this well. The good ones answer the four questions without getting defensive. The not-so-good ones make you feel like you're being difficult for asking.

The shortest version

If you're starting a switchgear manufacturer evaluation tomorrow, don't start with component brands. Start with responsibility. Ask each bidder to show you what verifies the complete assembly, and ask what the price does not include. Their answers will tell you more than any spreadsheet.

I learned that the expensive way. You don't have to.