This will be a hard one to find out. I have a central vacuum Drain Vac 2G20028-c , 12.5 amp at 120 volts.

It has a mini 15 amp breaker on the unit. The power going to the vacuum is on a normal square D breaker 20 amp breaker.

After a few weeks of being installed, every time I start the unit for the first time in the day, after about 30 to 90 seconds the 20 amp breaker in the panel trips (not the vacuum 15 amps). Then after resetting the breaker, I could vacuum all day long without any more trouble. The problem is still there (every time I use it !) after having done those thing :

  • Change the panel breaker for a news 20 amps

  • Change the 20 amps, 120v power outlet

  • Having check by the repair shop the vacuum, apparently all is fine

  • Change the entire cable between the power outlet and the main panel 20 amp breaker

  • Change the location and again the breaker in the main panel

Except changing the brand of my vacuum, I can't think of anything else. Could electric charge be a problem ? Could moisture be a problem ?

My vacuum outlet is pipe outside with a weather protection flap outlet, similar to those for laundry dryer.

  • What kind of motor does the central vacuum use? Posting a photo of the motor nameplate would be ideal -- that way, we can check and make sure the breaker in the panel was correctly spec'ed. Dec 7, 2015 at 5:01
  • Is the breaker you are using a GFCI breaker? A receptacle in an unfinished basement where the canister would be locate would normally require GFCI protection. I assume the system has been cleaned and there are no obstructions in any of the pipes and you normally get good performance?
    – ArchonOSX
    Dec 7, 2015 at 23:08

5 Answers 5


It is likely your breaker type...

The CVS Power Unit is engineered using a high-performance motor. As with all power units, it is recommended that the CVSPU have a dedicated circuit to ensure consistent operation.

ISSUE: Standard Square D Circuit Breakers May Cause Tripping Several dealers have reported nuisance tripping issues with the CVSPU. We have discovered that the some circuit breakers trip more easily when used to power the CVSPU. In discussions with a circuit breaker manufacturer, we were advised these breakers are not designed to operate high-performance appliances like central vacuums, air compressors and even some microwave ovens.

SOLUTION: Use High-Magnetic Breakers to Power CVSPU’s The manufacturer recommends using high-magnetic designed breakers like those listed below for dedicated circuits connecting to high-performance equipment. High-magnetic breakers can tolerate the high in-rush of current that occurs when high- performance appliances start, preventing nuisance tripping.

Please be aware that if you experience nuisance tripping with the CVSPU, replacing the breaker should eliminate the issue. For new construction, however, it would be preferable to discuss this issue ahead of time with the builder or electrician.

Recommended Breakers The recommended breakers to use with the CVSPU are listed below: • Square D (#QO115HM) for a 15 amp circuit • Square D (#QO120HM) for a 20 amp circuit • Square D Homeline (#HOM120HM) for a 20 amp circuit These breakers are available where electrical supplies are sold.


The panel breaker (or the vac mini breaker, too) switching off is telling you there is a problem in the electric line. This sometime happens when a Load (motor) is pulling to much current (amps) through the wire. Why the mini breaker on the machine didn't open first? It could be the reaction time is longer or it might be faulty. Since it is still shutting off even after replacing the outlet, wiring and breaker I would conclude that the problem is with the vacuum motor and circuitry. Since you may not have been able to witness the procedure when the motor was being repaired, get a second opinion at a different repair shop (if possible). From what steps you've taken so far the motor is the only component that may be at fault. Unless the repairs and upgrades to the electrical system are not completed correctly.

  • 2
    Just because the built in breaker did not trip, does not mean it's faulty. It could just be that it has a slower reaction time.
    – Tester101
    Dec 7, 2015 at 3:47
  • If the motor is faulty, why it would trip only once, than I could run ti as long as I want after this once trip/reset ? That does not make sense to me. If the motor was faulty, that would constantly trip, no ?
    – MaximeF
    Dec 7, 2015 at 4:00
  • @MaximeF You're assuming the system is stateless. The motor might be behaving differently when it's warmed up then when it's cold. Normally you'd never notice this difference but what's needed to trip the breaker might be just at where that difference happens. Either cold or warm the motor shouldn't be tripping the breaker. Dec 7, 2015 at 5:42
  • The mini breaker on the unit is highly likely to be a low cost thermal component that takes seconds to respond to an overload. The breaker at the panel is far more likely to be a electromagnetic type that trips much more quickly in response to an overload.
    – Michael Karas
    Dec 7, 2015 at 12:14
  • The 12.5A max specification is very likely the highest running current required for the unit when it is producing maximum suction through the worst case vent configuration through filters that are partially clogged. However the startup current for even a normally operating motor could be several times that high for a second or so. Now the motor itself could have some defect that causes a rise in the startup current to a level that easily trips an electromagnetic circuit breaker. It could be as simple as a set of bearings that are not properly lubricated or are on (continued)
    – Michael Karas
    Dec 7, 2015 at 12:26

If the motor uses a starting Capacitor this could be your problem. Vacuums draw the most current on startup when they are moving the most air. once a vacuum is dead headed,(no flow the vacuum usually speed up as they are moving no air). It is possible your starting cap is bad. Many large grinders and chop saws rated at 15A will trip a 20A breaker but then be fine I dont know if it is cold grease in the bearings but would check for a starting cap, as you have already upsized the breaker, the horse power rating of the vacuum motor would be needed to look up the correct size starting cap.


Large motors can pull a substantial surge of current on startup. Over here in Europe we have different types of breakers for loads with large inrush currents.

I don't know what practices are where you live but it wouldn't surprise me if you simply have the wrong type of breaker.


Some possibilities:

1. Your suction exhaust pipe (or flapper) may have a partial obstruction or a stuck flapper that temporarily reduces air flow when you first start vacuuming. Ensure there are no partial obstructions in your piping & that you flapper isn't sticking. Note: Rodents can sometimes die & get stuck in central vacuum piping/tubing.

  1. If possible, power your vacuum from a different branch circuit to determine whether or not the same problem occurs. If the problem doesn't occur, then the problem is likely in the old circuit. Double check the old circuit to ensure you are not overloading it. Another device/s may be connected to the branch circuit & you may be drawing too much power from all of the connected devices. If possible disconnect everything except the vacuum to test this possibility.

  2. Ensure the breaker that you installed is a quality breaker--some breakers aren't very good & trip easier than others.

  3. If your vaccuum system has a start capacitor, test it to ensure it is operating properly.

best regards!

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