How to Install an Air Filter (And Why Your Siemens Circuit Breaker Setup Matters)

Look, I'm a quality inspector. I sign off on deliverables—whether that's a printed brochure or a custom electrical assembly. My job is to catch what others miss before it becomes a problem.

Last week, I was reviewing a client's setup for a new air filtration system. They had a BMC (FB335/01) high performance air filter, a Siemens enclosed circuit breaker, and an Eco Pro solar generator. The question wasn't just 'how to install the filter.' It was: how do you wire it safely so the breaker doesn't trip every time the generator kicks on?

This guide covers exactly that. It's for anyone running a high-performance filter off a generator and a dedicated circuit. There are five steps. Don't skip step three—it's the one most people overlook, and it's the one that saves you from a $400 reorder.

Step 1: Verify Your Components and Their Specs

Before you touch a single tool, check what you're working with. This is the boring part, but boring prevents fires.

First, the BMC (FB335/01) high performance air filter. These are not your standard household filters. They handle high airflow for commercial or heavy-use environments. Look at the amperage draw on the label. A typical high-performance filter motor draws around 7-10 amps at 120V, but it depends on the model. If you don't have the spec sheet, measure it yourself with a clamp meter.

Next, the Siemens enclosed circuit breaker. I'm seeing a lot of these in solar setups. They're robust, but you need the right rating. If your filter draws 8 amps continuous, you don't want a 15-amp breaker; you want a 20-amp minimum to handle startup surge. Siemens publishes clear specs on their enclosures (siemens.com). The enclosure size also matters—if you're running the circuit through a 100-amp main breaker, that's fine, but the branch circuit needs its own appropriately rated breaker.

Finally, the Eco Pro solar generator. This isn't a generator in the traditional sense—it's a battery/inverter unit. Its output is clean, which is good for the filter motor, but limited. Check your generator's rated continuous wattage. A filter drawing 10 amps at 120V is 1,200 watts. If your generator is rated for 1,500 watts continuous, you have headroom. If it's closer to 1,200, you're running at the edge—and that's where things get interesting.

Step 2: Install the Air Filter Unit (Mechanical First, Electrical Second)

Most people want to wire things up and test them immediately. Don't. Install the filter housing first. It's easier to work on wiring when the unit is mounted securely.

For the BMC filter, check the mounting requirements. Is it ceiling-mounted or wall-mounted? The FB335/01 is a performance unit and often comes with a specific bracket or duct adapter. Use the included hardware or something rated for the weight—don't improvise with drywall anchors. I rejected a batch of installations in Q1 2024 because the vendor used standard plastic anchors for a filter that weighed 35 pounds. The fix cost us a $22,000 redo, including patching damaged drywall.

Once mounted, route the power cable to your Siemens enclosed circuit breaker. Use cable glands or conduit fittings. Loose wiring inside the enclosure is a no-go—I've seen it cause arcing. The Siemens enclosure should have a knockout for the cable. Use the correct size.

Step 3: Calculate Your Startup Surge (The Step Everyone Misses)

Here's the thing: electric motors draw more power when they start up. This is called 'inrush current.' A filter motor that draws 8 amps running might pull 40-60 amps for a split second at startup.

Your Siemens enclosed circuit breaker is designed to handle this—breakers have a 'high interrupt' rating for short-duration surges. But your Eco Pro solar generator might not.

I tested this scenario last month at my own facility. A 9-amp filter motor on a 1,500-watt generator. The generator's inverter wouldn't supply the inrush peak. The voltage sagged, the breaker tripped, and the filter never started. Everyone thought the filter was defective. It wasn't. The generator just couldn't handle the startup load.

The fix: either get a generator with higher surge capacity (look for one rated for at least 2x the filter's running watts) or use a soft-start kit for the motor. Soft-start kits limit inrush, dropping it from 60 amps to maybe 20. They cost $50-100. On a 50,000-unit annual order scenario, that's $5,000. For a single installation, it's an easy insurance against frustration.

Step 4: Wire the Circuit Breaker and Generator Properly

This is the part where people get creative. I've seen setups where the filter is plugged directly into the generator with an extension cord. That works for testing, but for a permanent installation, you need a dedicated circuit.

Wire your Siemens enclosed circuit breaker between the generator and the filter. Use appropriately rated wire—12 AWG for a 20-amp circuit is standard for 120V. The breaker should be sized to protect the wire, not the appliance. If you use 12 AWG wire, a 20-amp breaker is correct. If you've got a specific setup, Siemens provides software (their 'Breaker Selection Tool') to match wire specs and load requirements.

Connect the generator's output (L/N/G) to the input terminals of the Siemens enclosure. The output terminals connect to your filter. Follow the markings—LINE and LOAD. Get them reversed, and the breaker won't trip when it should. That's a safety issue I can't overlook.

Between you and me, I once had a client who wired the generator output directly into the filter without a breaker. 'It's only 1,200 watts,' they said. Six months later, a fault in the filter motor caused an arc that melted the generator's internal wiring. The generator cost $1,200 to replace. The breaker would have cost $30.

Step 5: Test, Then Secure Everything

After wiring, turn on the generator first. Let it stabilize—solar generators with inverters sometimes need a minute before they deliver clean power.

Then, turn on the Siemens circuit breaker. Listen for arcing (you shouldn't hear any).

Finally, start the filter. If it trips immediately, you've got a surge issue (refer to Step 3). If it runs but the breaker feels hot after 10 minutes, you're close to the limit—check your amperage draw with a meter. The ideal is that everything runs at 60-80% of rated capacity. Running at 95% is possible, but it's inviting premature failure.

Common Mistakes I See

• Skipping the generator's manual. The Eco Pro generator has specific limitations on motor loads. Some models say 'resistive loads only'—that means no filter motor. Check before you wire.
• Using too thin wire. 'What's wire got to do with it?' Everything. Thin wire creates voltage drop under load, which the motor interprets as 'time to pull even more amps.' That's a feedback loop that destroys motors.
• Forgetting a ground. The Siemens enclosure needs a ground wire bonded to the generator's ground. If ground is missing, a fault in the filter can electrify the enclosure's metal case.

One last thing: I'm not an electrical engineer, so I can't speak to code compliance in your jurisdiction—that's what licensed electricians do. My expertise is in catching mistakes before they cost you time and money. If you want a checklist, this is it. Stick to it, and your installation will hold up.