Why don't water heaters require GFCI protection

The question boils down to:
whats an acceptable level of leakage current flowing on the equipment ground of a hard wired appliance?
If a water heater has a 30A inverse time breaker it will probably let 30 amps flow on the equipment ground indefinitely.
If you touch the metal frame while 30A is flowing on it and the EGC is intact will you feel anything? Will you be shocked?
 
tortuga said:
The question boils down to:
whats an acceptable level of leakage current flowing on the equipment ground of a hard wired appliance?
If a water heater has a 30A inverse time breaker it will probably let 30 amps flow on the equipment ground indefinitely.
If you touch the metal frame while 30A is flowing on it and the EGC is intact will you feel anything? Will you be shocked?
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Are you barefooted on a wet concrete floor?

Do you feel anything when you touch a meter can that has 30 amps flowing on the neutral? Do you feel anything when you touch a neutral bar that has 30 amps?
 
tortuga said:
The question boils down to:
whats an acceptable level of leakage current flowing on the equipment ground of a hard wired appliance?
If a water heater has a 30A inverse time breaker it will probably let 30 amps flow on the equipment ground indefinitely.
If you touch the metal frame while 30A is flowing on it and the EGC is intact will you feel anything? Will you be shocked?
Click to expand...
I think the issue would be high mineral content of the water in the water heater, with non metallic plumbing, the water would effectively become “hot” electrically.
 
ptonsparky said:
Are you barefooted on a wet concrete floor?

Do you feel anything when you touch a meter can that has 30 amps flowing on the neutral? Do you feel anything when you touch a neutral bar that has 30 amps?
Click to expand...
Never noticed anything.
Add to that list all the ranges and dryers with neutral current on the frame.
I suspect most of the GFCI requirements for fixed (hard wired) equipment may be overblown.
 
tortuga said:
The frame is metal, so yeah there might be a little voltage on the frame if a heavy fault current is flowing, but I really
I have not read any peer reviewed research that shows the need to have 5mA ground fault protection for any fixed appliances hardwired to a EGC unless its a pool or other special situation. I could see lowering the threshold perhaps even to 30mA but 5mA seems excessive.
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IMHO for hard wired appliances such as water heaters or the like something like an electromechanical RCD would make far more sense than the electronic residual current detection used in GFCIs or GFPEs.

Why have more delicate electronics sitting there consuming power when the residual current sense coil can trip a breaker when perhaps 100mA of leakage current flows. And when you have a reliable hard wired EGC, you don't need a more sensitive ground fault detection.
 
tortuga said:
Never noticed anything.
Add to that list all the ranges and dryers with neutral current on the frame.
I suspect most of the GFCI requirements for fixed (hard wired) equipment may be overblown.
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Supposedly this all got started from a hvac compressor that was wired wrong and killed a technician.
I went behind another electrician that wired a hot tub wrong, luckily it didn’t heat up, and the owner wanted me to take a look at it. The installer did not have it on a gfi breaker, landed one of the hots to the ground lug, and the ground to one of the power terminals.
 
hbiss said:
Does your wife know what you are doing in the basement? :love:

-Hal
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Too funny, :)

I wish it was in the basement hbiss.
As it is, it's locate in the middle of the house, and, I've been checking in on it for the last 30 years. :)

Jap>
 
tortuga said:
The question boils down to:
whats an acceptable level of leakage current flowing on the equipment ground of a hard wired appliance?
If a water heater has a 30A inverse time breaker it will probably let 30 amps flow on the equipment ground indefinitely.
If you touch the metal frame while 30A is flowing on it and the EGC is intact will you feel anything? Will you be shocked?
Click to expand...
The shock hazard is equal to the voltage drop on the EGC. 30 amps on a 10 or 12 AWG is unlikely to create a voltage drop high enough to be a shock hazard.
 
hillbilly1 said:
I think the issue would be high mineral content of the water in the water heater, with non metallic plumbing, the water would effectively become “hot” electrically.
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Our water is very hard (18 grains) and I have all copper piping. A wire connected to the hot side of a GFCI receptacle and placed in the running water will not flow enough current to trip the GFCI. Not sure water would be conductive enough to result in a shock hazard.
 
don_resqcapt19 said:
Our water is very hard (18 grains) and I have all copper piping. A wire connected to the hot side of a GFCI receptacle and placed in the running water will not flow enough current to trip the GFCI. Not sure water would be conductive enough to result in a shock hazard.
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Seems to be an issue with lake water. It appears to have enough conductivity to electrocute someone.
So it wouldn’t be so far fetched that tap water wouldn’t.
 
hillbilly1 said:
Seems to be an issue with lake water. It appears to have enough conductivity to electrocute someone.
So it wouldn’t be so far fetched that tap water wouldn’t.
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One huge difference is body contact area in a lake vs contact with running water
Maybe in a bathtub with running water, but only if there is a ground path which is not very likely given most drainage piping is non-metallic.
 
don_resqcapt19 said:
One huge difference is body contact area in a lake vs contact with running water
Maybe in a bathtub with running water, but only if there is a ground path which is not very likely given most drainage piping is non-metallic.
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I’ve been shocked by a brass faucet mounted to wood with cpvc plumbing standing in mud. Mud was electrified by a damaged uf cable that was not on a gfi circuit.
 
marmathsen said:
What is the rationale for GFCI protection of hardwired properly grounded appliances?
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Influence by GFCI manufacturers. Many things been added since about 2005 NEC or so that have little justification for why we should need to protect them with GFCI. When they have used real world incidents, there usually is other code issues involving improper or compromised equipment grounding conductors that likely would have allowed enough fault current to open overcurrent protection.

When they first started requiring GFCI protection on certain three phase receptacles the justification was essentially "we have the ability to do that now" and not that there were any real world incidents to suggest it may be necessary.

I am not an anti-GFCI person, but I also believe it is mostly needed on 5-15 and 5-20 when it comes to receptacles and not so much on other receptacles that seldom if ever have a missing or compromised equipment grounding pin nor is it normally necessary on hardwired equipment other than maybe art 680 applications and maybe a few other limited applications.
 
marmathsen said:
What is the rationale for GFCI protection of hardwired properly grounded appliances?
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My understanding from @don_resqcapt19 is the substantiation provided to the NEC Code Making Panel of a single residential electrocution death at HVAC equipment. Not to say a single death is not tragic.
I dont remember the source but it has come up in several threads. @don_resqcapt19 usually has very good sources and often catches my mistakes and corrects me (thanks don), but I have not verified the one death claim. Someone from NEMA made a public comment to our state electrical board that to the effect that is was many deaths. It would be interesting to see the sources for these claims.
 
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