Anyone had any issues with this type of equipment and nuisance tripping AFCI circuit breakers?
Just wondering, because this equipment usually plugs into standard 120V receptacles and is normally located in a living room, bedroom or other area where AFCI's are currently required to be used.
Experiencing first hand, the tendency of AFCI's to trip unexpectedly when motor loads are involved, like vacuums, hair dryers, power tools, etc... I don't think it’s safe to rely on their integrity, especially in this instance. I can't see any option in the NEC to avoid the potential AFCI issue, other than locating the equipment in a bathroom, kitchen, garage, unfinished basement or possibly finding a 240V unit, but this negates the purposefully intended ease of installation for an otherwise already complex peice of medical equipment that performs a life saving medical procedure.

Hi there KJay,
My mother has one of these machines installed at her place.
Although we don't use AFCI's over here, I would have some problems with a machine such as this being connected to a circuit protected by one of these devices.

First off, I would make sure that the dialyser is actually 120V, the one my mum uses is 4kW @ 230V (single phase), it heats it's own water (for the hot wash after dialysis has taken place).

There are 2 motors in the unit, the first is a small geared down thing that drives the peristaltic pump that circulates blood through the patients body.
The second is a smaller drive that operates an iron infusion system.

Bear in mind, KJay, that these machines are very sensitive to the environment around them, I wouldn't personally install one in a damp area.
Having said that, you also have to think of the welfare of the person that is going to be hooked up to this machine for possibly up to 5 hours a day, up to 3-4 days a week, I'd at least want somewhere comfortable.

These machines also require a drain with a P-trap and a supply of cold water.

Dialysis units have backup batteries in them (like all medical equipment), but having the power cut out during dialysis can be distressing for patients.

The unit my mum has, is supplied via a 6mA RCD (GFCI), the unit is regularly serviced by the health services technician, every 3 months.
Even getting in contact with one of these guys, would possibly give you all the info you need, I mean if they don't know, no-one does.

Hope this is of some help.

P.S: I'm not trying to make any sort of a social statement here, but these machines could become more prevalent in the years ahead, kidney disease is on the increase.
It is good though that we have the technology to keep people alive until a transplant becomes available.

Interesting situation, is this real; life experience and does it work on a GFCI?
If so, this is not a ground fault situation and just a false arc problem.
You could try another brand AFCI but I know that is tough if you can't find the elusive "device" and don't want to install a sub.
Personally I would just put a regular breaker in there and say "come and get me copper" if it was my family member who needed the machine. (maybe on a dedicated circuit)

the one's we install are required by the manufacturer to be on a GFCI. If the power fails during treatment, they can essentially reverse the process and start over later. It's a bit different apparently then the process at a renal center.

I wouldn't be concerned.

Greg,
That is what I personally agree with, myself, other than having an RCD socket-outlet at point of use (mainly because that is what is required for medical equipment used in domestic premises here).

The RCD that my mum uses has never tripped during the use of the dialysis machine, mainly because between the technician and myself (the installing electrician), we worked out how it could be done the best (as in, the safest result).

She knows to test the RCD, every time before the machine is plugged into the socket-outlet, if the test fails, the socket won't deliver a supply and I would normally get a phone call, that hasn't happened yet.

BTW Greg,
The machine is on a dedicated circuit, it can also be interfaced into a generator, if need be, I have installed an appliance inlet below the switch-board, with a smoothing unit in the back of the panel itself.
The dialyser is worth about NZ$80K and has some very sensitive computer controls, burning that out with a genny would probably not be a terribly good look.

I would do the same without hesitation, but what would you do if this were for a paying customer that has called you to solve this nuisance trip problem?

GFCI protection makes perfect sense here and I don't see this as an issue, but IMO the battery backup feature and the ability of the equipment to reverse the process on power failure are intended just as such… emergency backup procedures, not as common conveniences.
I don't think it is prudent or necessary to put the person thru any additional stress or the inconvenience of starting over again 1-1/2-hours into a procedure that may take upwards of 4-5 hours to complete, when this can be greatly lessoned by the absence of AFCI protection for that particular circuit.


As a sidebar:
From my experience, there is no way that the majority of AFCI cb nuisance tripping is taking place because of 30mA [GFI] ground faults in appliances, as these appliances will function without incidence on much more sensitive .06 mA [GFCI] protected circuits and receptacles. The arc fault sensing portion has to be the problem.

The thing I just don't understand about AFCI circuit breakers and nuisance tripping, is that all 120V portable and window type AC units have had AFCI protection built into the cords for years and they seem to operate flawlessly without this false tripping.
Is it possibly because these factory installed cord mounted afci's are tuned to the specific arc signature of the appliances they are connected to?

The problem with AFCI was we allowed the manufacturer to decide what an arc was and they each have their own proprietary method of deciding that.
It has very little to do with GFCI that has a defined parameter no matter how much people try to draw the parallel.

That is the reason "testers" have to be called "indicators".
For equipment that trips one, I agree the first step is trying it on a GFCI to isolate the major legitimate cause of nuisance tripping. If it can run on 5ma GF protection, there is simply something in the current curve that tricks an AFCI. I am not sure that can be blamed on the equipment design and without attaching some culpability to the AFCI designer.

KJay:
If you had this situation here, I would suggest you do the following:

Refer to mfg instructions for the unit.
If unit requires GFI, per mfg, then GFI device for the units location.
Submit a Variation per UCC regs for this install.

BTW, If you were here (NJ) AFCI's are not mandatory until Oct 1, 2009.

Window AC units have LCDI on the power cord not AFCI. The LCDI detect leakage to a shield or screen on the outside of the power cord and trip.

You're right. That's what happens when I attempt to go by memory alone.

The only problem is... now I can't even give credit to AFCI's for performing satisfactorily in this application.

I'm curious why air conditioners are the target for LCDI protection. From what I can find so far on these, it's just for fire protection. But don't see how air conditioner cords have a monopoly on causing fires.

From years as a firefighter, I have seen many fires caused by window units. Mostly at the plug. I have also seen many fires caused by space heater cords. Lots of window units and space heaters are used in older homes with substandard wiring. These are often plugged into extension cords not rated for the current. NFPA uses fire reports filled out by the fire dept. to develop codes and standards. With a AC unit, the fire was caused by electrical short in the unit. With a space heater , the fire was caused by the heater. There is little effort ether by the fire dept, NFPA or others to determine the exact cause. I can say by my experience that many space heater fires were caused by extension cords and poor connections (plug strips & multi plug adapters) rather than the use of the heater itself. (near combustibles or tip over ) Most firefighters and arson inspectors are NOT forensic electrical inspectors and do not detail the cause of the fire in the report. Robert

I am not sure how a dongle on the cord can protect from problems on the line side of the cap.

It cannot. Although LDCI are required now, most fires and overheating I saw were at the cord cap. Most newer AC units pull far less current than the older units. I have a new unit I have for use after hurricanes. It is 8000 btu and pulls 5.2 amps full load. I have a customer has the same size unit but its 15+ years old, it pulls 12a When I wrote fire reports that were sent to the state and NFPA, when a AC unit was involved and it involved a cord or plug, it was just marked AC cord. I am not saying LDCI are not a good idea, just that from personal experience, I saw few cord fault caused fires. I do know the NFPA encouraged fire dept. to be as detailed in their reports as possible to help them develop codes to prevent fires. Trouble with this is few firefighters have much if any electrical know how so only general information is put on the fire reports. I have read many fire reports that said "short in AC cord " when in fact the cord cap melted.

I suspect these problems are more related to worn out 40 cent receptacles than anything. I know my wife burned up a vacuum cleaner plug in this house shortly after we moved in. The receptacle in the living room was burned too. I ended up buying spec grade receptacles and doing them all. After that I went over and did all my Mom's receptacles and switches too.
Maybe what they really need is a thermal cut out in the plug.