Serious / VFDs trip AFCIs?

[ptonsparky]

Dealing with AFCIs.

I have a BR style panel in my home. Wife wanted this particular style of home & if she is happy things are just usually better or at least bearable. Not by any stretch of the imagination a mobile home. However I did get to use a cheap VFD on my well. Being the TA that I am, I did not put line filtering on the supply side. The combination style AFCI(s) trip whenever fixture(s) on one of the protected circuit is turned on and the VFD cycles on. Usually that means the water to air heat pump has also come on. Once the AFCI is reset they stay on while the VFD is doing its thing.

My office laser printer causes more VD as it cycles than do the heat pump and well. Usually we don't know when either of them turn on.

Okay, any guesses as to if the line reactor will help, or do I just start ripping out the AFCIs?

 

[cadpoint]

Dealing with AFCIs.

My office laser printer causes more VD as it cycles than do the heat pump and well. Usually we don't know when either of them turn on.

This question is based on what I believe was one of your previous posts - (and I believe this is correct-from a previous post, if I'm wrong please disregard the first statement-1 week to 10 days back)

First is why do you have 15 amps for the computer system. I know it's not required but I have a single circuit - 20 AMP for my computer power needs.

It sounds like you have loaded up every circuit to 80%. These motors are pushing every circuit over it's limits.

There frankly sounds like no isolation of any of this equipment -applications, anywhere.

Why are you even running all this stuff off the AFCI's? Last I looked the only tap off an AFCI circuit is for the Smokes, and old 2005 one was still allowed to tap for a outdoor GFCI house receptacle, but that is based on 20 amp service.

Using 15 or 20 amps, I would isolate a few single circuits to some of this equipment; well pump house and/or water heater circulation pumps.

Your stressing this motors and pumps, IMO, besides you shouldn't make your
wife into a plumber's wife... (IE something always needing fixing )

You will play greatly in the near future for these device that will fail due to high loading that your working them through.

Keeping Momma happy is good thing as much work as it takes and no short cut's... while you might not get direct praise nor proper appreciation of your actions, some minor modifications on your part will keep any and everyone out of the electrical panel.

 

[ptonsparky]

All of these items are on separate circuits. The home was wired to 05. I made them replace the non combination style AFCI's with combination. An "Oops" on their part. I used combination AFCIs in the basement area that I was responsible for. The old style AFCIs did not seem to have a problem for the time they were in. No short cuts were taken other than the lack of a line reactor. Their work was megged and readings logged.

There is no pump house. The VFD is mounted in the basement area next to the Service Entrance. I tried to make things malfunction this morning to no avail. It is a nice cold snowy day so I will leave everything on to try and catch when or if it happens again.

I could possible bring a 20A circuit to the office, but for no more than what I print at home it's not worth the trouble. Besides it will move in a few months anyway.

 

[jim dungar]

Depending on their 'pre-charge' circuit it is possible that your VFD has a capacitor connected line-ground on its input (many do). An input line reactor will not help in this case. You would need an isolation transformer instead.

 

[gndrod]

Dealing with AFCIs.

However I did get to use a cheap VFD on my well. Being the TA that I am, I did not put line filtering on the supply side. The combination style AFCI(s) trip whenever fixture(s) on one of the protected circuit is turned on and the VFD cycles on. Usually that means the water to air heat pump has also come on. Once the AFCI is reset they stay on while the VFD is doing its thing.



Okay, any guesses as to if the line reactor will help, or do I just start ripping out the AFCIs?

If the water well pump-motor and heat-pump is outside the house, they are not required to be AFCI protected. Using a motor controller on the well pump indicates to me a 1.5 hp or larger motor is being used or a 2-wire system was not considered. In either case, the well circuit is isolated on its own and should not have extraneous problems. If what I am describing is not what you have, please disregard and feel free to give additional details. rbj

 

[ptonsparky]

The well & heat pump are not on AFCIs. They are on their own branch circuits. Now that I am trying to monitor when the AFCIs trip, they haven't.

 

[mxslick]

Try the old tv repairman's trick: put a picture of yourself inside the panel door so the afci's know you're always watching them. :grin:

 

[gndrod]

The well & heat pump are not on AFCIs. They are on their own branch circuits. Now that I am trying to monitor when the AFCIs trip, they haven't.

Getting a better idea now. So from what I gather, the well pump nor the heat pump do not trip their respective OCPD. Sounds like the old AFCI (Series Arc protection) had no problems. I am guessing that the new Combination AFCI Parallel Arc protection may be cross-coupling with the well and/or heat pump circuits somewhere along the pathway back to the panel. rbj

 

[ptonsparky]

The well and heatpump are in separate emt runs away from the AFCI circuits. Only place common is the panel & even then the circuits are on opposite sides and not accross from each other. I did change the way the VFD works with the Heat pump. It is now ON whenever the HP calls.