Floating Voltage in Bay Boxes causing interference with Credit Card Acceptance...

I added WashCard credit card acceptance a few years ago to our self serve bays while converting one bay to a touchless automatic. We put the new ss boxes in next to our old coin acceptor boxes. Just last month, one bay started not accepting cards. Now here's the interesting part- it would accept cards all day long as long as the washcard bay box was open. Close it and it wouldn't work. Then we noticed that the boxes (washcard and old ss coin accept) were carrying about 3.8 volts at all times. Test anywhere on the box and we get a reading of 3.8 volts... Washcard thinks that this voltage in the box may be interfering with the credit card signal, since it is only 5 volts.

Next, the Wash Select II payhead in our automatic started having trouble. Open the door and it would accept cards every time. Close the door and it would accept cards for an hour or 2 and then quit. Open the door, it would work again. It didn't seem to have any "floating" voltage, but now it does. There are about 4 volts anywhere there is metal in the payhead. As of today, it will only accept cards with the door open. The door still registers 4 volts though. I have double and triple checked that there are no pinched wires of any kind.

Also today, there are now 4 volts in all the other self serve bays as well, although they seem to process cards with no problem.

Any suggestions on dealing with this electrical ghost would be very welcomed. Thanks!

Does yours use a floating common (two legs of 12V AC) or a 24V AC and neutral?

MEP001 said:

Does yours use a floating common (two legs of 12V AC) or a 24V AC and neutral?

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I don't think "floating" voltage was the word I should have used. We use a 24V AC and a neutral. (as far as I know!)

The way to tell would be to read each side of the transformer to ground.

Most self-serve equipment is run off a 240V to 24V transformer, which means two 12V AC legs.

RockyMountain said:

I added WashCard credit card acceptance a few years ago to our self serve bays while converting one bay to a touchless automatic. We put the new ss boxes in next to our old coin acceptor boxes. Just last month, one bay started not accepting cards. Now here's the interesting part- it would accept cards all day long as long as the washcard bay box was open. Close it and it wouldn't work. Then we noticed that the boxes (washcard and old ss coin accept) were carrying about 3.8 volts at all times. Test anywhere on the box and we get a reading of 3.8 volts... Washcard thinks that this voltage in the box may be interfering with the credit card signal, since it is only 5 volts.

Next, the Wash Select II payhead in our automatic started having trouble. Open the door and it would accept cards every time. Close the door and it would accept cards for an hour or 2 and then quit. Open the door, it would work again. It didn't seem to have any "floating" voltage, but now it does. There are about 4 volts anywhere there is metal in the payhead. As of today, it will only accept cards with the door open. The door still registers 4 volts though. I have double and triple checked that there are no pinched wires of any kind.

Also today, there are now 4 volts in all the other self serve bays as well, although they seem to process cards with no problem.

Any suggestions on dealing with this electrical ghost would be very welcomed. Thanks!

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RockyMountain,

We had the bare footed people (including myself!) get the yeeee tingle from touching our coin boxes about 2 years ago when we were testing suitability of a coin mech on our revised coin boxes. We ran a green 12 gauge wire fastened on the stainless steel coin box back to a suitable earth ground & it took care of the problem.

I have been told by an electrical (electronics) engineer that one of the tests for a good ground is to use a good multimeter that measures ohms to verify that there is less than 1 ohm reading between the closest to the electronics ground (on a printed circuit board preferably) & the actual ground rod in wet earth. Preferably the ohm reading would be around .5 to .6 of an ohm. http://www.msha.gov/S&HINFO/TECHRPT/GROUND/GROUNDRE.HTM

Our car wash installer (Specialty Equip) back in 1987 made sure that one side of the secondary of all our class two transformers were bonded to the neutral of the main entrance panel. Based on our limited experience & with consultation with a bonafide electronics engineer that is the preferred way. Then when you check for current you get 24VAC. For testing purposes only, one AC voltage tester lead could be to the ground wire or the neutral wire. Just because you meter shows continuity between the neutral & ground does not mean that they have the same path of electrical potential ... so be very careful to not forget about that distinction.

I remember when I was in Guatemala on a Mission Trip staying with a family ... & getting significant electrical shocks (tingling) every time I took a shower ... it had something to do with "lack of complete enough knowledge" on the part of the people setting up the shower. Another reason or excuse or whatever ... the installer may have had a bit too much VODKA ... I am not sure.

mike walsh http://kingkoin.com/USA_Deficit_Reduction.html

mjwalsh said:

RockyMountain,
We ran a green 12 gauge wire fastened on the stainless steel coin box back to a suitable earth ground & it took care of the problem.

mike walsh http://kingkoin.com/USA_Deficit_Reduction.html

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Do you think it's likely that these 4 volts are what's causing the card not to process in the one self-serve box and in the automatic payhead? There are also 4 volts in the other 2 self serve bays and those process cards nicely...

RockyMountain said:

Do you think it's likely that these 4 volts are what's causing the card not to process in the one self-serve box

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I'm not an electrician, I'd be asking here on the forum. But yes I think it is likely. Could be something else, but grounding the door as Mike describes is mandatory as far as I'm concerned. In addition its both easy to do and probably the simplest thing to eliminate from your list of possible causes.

FYI, I have Etowah Valley's credit card system. The install instructions are VERY explicit in stating that the door MUST be grounded, otherwise they wont even talk to you about other possibly problems. (NOT screwed into the cinderblock wall, 4' deep earth ground... ie run it to the ground in your circuit panel.)

Rocky, Are your boxes daisy chained or is each bay wired directly to the site controller? I have had my WC system for 4 years and boxes are not grounded and have not had this problem. One site daisy chained and the other a direct wire to site controller.

I would do some troubleshooting to start off. Disconnect the power plugs on each WC bay controller & disconnect the heater for the card reader and see if the voltage is still there. If the voltage is gone, plug in each bay and test for the voltage after bay plugged in and after reconnecting the heater.
If after unplugging the WC plugs and the voltage is still there, do the same with coin acceptors.
Do you happen to have IDX coin acceptors?

Stuart said:

Rocky, Are your boxes daisy chained or is each bay wired directly to the site controller? I have had my WC system for 4 years and boxes are not grounded and have not had this problem. One site daisy chained and the other a direct wire to site controller.

I would do some troubleshooting to start off. Disconnect the power plugs on each WC bay controller & disconnect the heater for the card reader and see if the voltage is still there. If the voltage is gone, plug in each bay and test for the voltage after bay plugged in and after reconnecting the heater.
If after unplugging the WC plugs and the voltage is still there, do the same with coin acceptors.
Do you happen to have IDX coin acceptors?

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The boxes are not daisy chained. Each bay is wired directly to the site controller.
Thanks for the troubleshooting sequence. The washcard tech's have been pleasant to work with, but sure didn't have these suggestions.

The acceptors are all working right now, but I feel like it is only a matter of time before I run into trouble again. It seems that when all the bays are busy is when the card readers start to fail.

I do have IDX coin acceptors...

We added a grundfos pump and increased some copper pipe from 1 inch to 1 1/2 inch to get more water and to help our new Navien heaters to function better. There were several ground wires connecting different pipes and I'm not sure they got them all back in the correct spots. Even the electrical conduit running across the wall shows 4 volts... Is this lack of grounding copper pipes likely the source of our voltage issue?

I'd say yes, if the conduit even has four volts.. Probably leakage voltage, but it shouldn't be there. Just curious, is the mystery voltage AC or DC?

You mentioned you have voltage in the ER , I am going to go out on a limb and say you have metal conduit from the ER to the coin boxes and that the problem is originating in the ER.
This would explain why it is showing up in all coinboxes and auto cashier.

Either way you will need to systematically check all the plumbing, equip stands, etc to verify proper grounding. If you have metal conduit see if there is a way to isolate the coinboxes from the ER just incase you get a high voltage accident in the ER which will transfer to your customers in the bay. Good luck

slamdvw said:

I'd say yes, if the conduit even has four volts.. Probably leakage voltage, but it shouldn't be there. Just curious, is the mystery voltage AC or DC?

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AC. What is leakage voltage and what could be possible causes?

Leakage voltage is coupled via capacitance from one wire to the next. ( take your meter lead and touch the insulation on a wire known to have voltage on it. ) Eliminating it, is making sure your grounds and conduits are bonded together.

If you have a loose or corroded conduit connector, "spliced" a conduit with a piece of PVC flex.., anything like that to make it lose it's reference to ground.