How Would You Handle this Call

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Little Bill

Little Bill

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Tennessee NEC:2017
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Semi-Retired Electrician
I get a call from one of my customers stating he is getting shocked on the metal housing of a new machine he just bought. The machine is some type of freeze-dried/vacuum sealed device. He states he called the mfg and they were going to send him a video of how to take the cover off to check the grounding terminations. He went on to state that he was barefoot, on his concrete garage floor. RED FLAG #1
I asked if he had it plugged into a GFCI receptacle. He said no, that he removed the GFCI because the instructions said to put it on a NON GFCI circuit. RED FLAG #2

I tried to explain to him that the mfg knew there was leakage current or they wouldn't have said not to use a GFCI. His only reply was "the machine is sold all over the world, took me 2 months to get it, and cost $4000." I told him none of that mattered and most likely the machine wasn't listed with a proper testing agency. Anyway, he wants me to come and check it out. Given the fact that no GFCI is supposed to be used, I don't know of anything I can do other than go and collect his money for a service call!
 
Little Bill said:
I get a call from one of my customers stating he is getting shocked on the metal housing of a new machine he just bought. The machine is some type of freeze-dried/vacuum sealed device. He states he called the mfg and they were going to send him a video of how to take the cover off to check the grounding terminations. He went on to state that he was barefoot, on his concrete garage floor. RED FLAG #1
I asked if he had it plugged into a GFCI receptacle. He said no, that he removed the GFCI because the instructions said to put it on a NON GFCI circuit. RED FLAG #2

I tried to explain to him that the mfg knew there was leakage current or they wouldn't have said not to use a GFCI. His only reply was "the machine is sold all over the world, took me 2 months to get it, and cost $4000." I told him none of that mattered and most likely the machine wasn't listed with a proper testing agency. Anyway, he wants me to come and check it out. Given the fact that no GFCI is supposed to be used, I don't know of anything I can do other than go and collect his money for a service call!
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I would make sure to follow all applicable codes and exercise good judgment. I would also try to educate the customer about the risks involved before taking his money. Put everything including your recommendations in writing and don’t feel pressured to go along with the manufacturer and customer. It’s not going to matter how much the machine cost the customer if he’s dead. Not something you want to get dragged into. More importantly I wouldn’t open or tamper with anything in the machine unless the manufacturer provided written permission and instruction to do so. Otherwise, if something unfortunate were to happen, I could see the manufacturer blaming you for tampering with the machine.
 
I would measure the open-circuit voltage, connect and measure the EGC leakage current, and note both with your invoice.
 
I have no intention of opening up the machine, especially since it's new and also for liability reasons. I might if they gave me the permission in writing, but I really don't want to get involved at all!
 
Setting up machine in bedroom/office, after Megger test, fixing any plug polarity or bonding issues in that bedroom, and possibly putting GFCI back in garage, is the only legal option.
 
Little Bill said:
I have no intention of opening up the machine, especially since it's new and also for liability reasons. I might if they gave me the permission in writing, but I really don't want to get involved at all!
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I think the value added here is working with the customer to reduce his (and your) liability while accepting his money. Contact the manufacturer and get clear documentation to protect yourselves. Explain any inconsistencies with what the manufacturer is proposing vs. what is allowed per code. Put it back on them.
 
Little Bill said:
Anyway, he wants me to come and check it out.
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He already tested it. Maybe not by a recommended method, but just as accurate. ;)

I wouldn't do a thing except say that yup, there's leakage but there isn't anything I can do about it. My responsibility ends at the receptacle. Take it up with the manufacturer.

-Hal
 
Xptpcrewx said:
I think the value added here is working with the customer to reduce his (and your) liability while accepting his money. Contact the manufacturer and get clear documentation to protect yourselves. Explain any inconsistencies with what the manufacturer is proposing vs. what is allowed per code. Put it back on them.
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In my area, contractors will try to replace the fuse box first, before considering other services.

If they can't upgrade the service, its not worth rolling the truck.
 
hbiss said:
He already tested it. Maybe not by a recommended method, but just as accurate. ;)

I wouldn't do a thing except say that yup, there's leakage but there isn't anything I can do about it. My responsibility ends at the receptacle. Take it up with the manufacturer.

-Hal
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Solid advice but I don’t think it addresses the problem. The customer already took it up with the manufacturer and they are proposing the customer remove the GFCI.
 
Solid advice but I don’t think it addresses the problem. The customer already took it up with the manufacturer and they are proposing the customer remove the GFCI.
GFCI is already removed by clients, says in post #1.
I had a client that had a plug in Sauna that said don’t connect to GFCI.
Told owner it has to be GFCI in the location your installing it. Then said if it trips then the manufacture Has issue on there end. Nothing really you can do show him the code section and walk away.
 
Separate from the GFCI issue is the value of checking for proper grounding of the receptacle (especially as the customer swapped this) and check for bonding of the rebar in the concrete floor.

If the EGC is intact, then you should be able to have significant current flow without a shock hazard.

If the concrete floor isn't bonded (I may not be required) then there might be a voltage difference between bonded metal and the floor. It is entirely possible that the shocks are not coming from the machine's power circuit at all.

-Jon
 
winnie said:
Separate from the GFCI issue is the value of checking for proper grounding of the receptacle (especially as the customer swapped this) and check for bonding of the rebar in the concrete floor.

If the EGC is intact, then you should be able to have significant current flow without a shock hazard.

If the concrete floor isn't bonded (I may not be required) then there might be a voltage difference between bonded metal and the floor. It is entirely possible that the shocks are not coming from the machine's power circuit at all.

-Jon
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when is bonding of rebar in the floor ever required, except maybe in a dairy barn.
 
petersonra said:
when is bonding of rebar in the floor ever required, except maybe in a dairy barn.
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It probably isn't required. I'm confusing concrete floors with footers.

But required or not, potential between the EGC and concrete caused by something external to the equipment in question could be causing the shocks. If the customer wants to use the machine in bare feet then they might want this addressed code or no.

-Jon
 
petersonra said:
when is bonding of rebar in the floor ever required, except maybe in a dairy barn.
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It's a side effect of various requirements when a stand-alone garage is built on a slab foundation with a thickened edge as footer, the bottom of the footer is in contact with the earth, and the slab has reinforcement that is tied together with the footing rebar. I would expect that to be a common arrangement in new construction in CA.

Cheers, Wayne
 
winnie said:
It probably isn't required. I'm confusing concrete floors with footers.

But required or not, potential between the EGC and concrete caused by something external to the equipment in question could be causing the shocks. If the customer wants to use the machine in bare feet then they might want this addressed code or no.

-Jon
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It seems to me that if there is a problem with voltage between the concrete and EGC, it would have manifested itself long before the freeze dryer showed up. it seems unlikely to me that this guy started going barefoot in his garage after the freeze dryer showed up.
 
Just hooked up a CNC machine today, had to change the end on the cord because it was none standard in the US, traced the wiring in the cord, because green doesn’t always mean ground overseas! Found no ground on the machine end, just the two hots. I bet that machine is not grounded either.
 
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