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Tingling sensation in Hot tub water

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J

jraymond

Member
Location
Traverse City, MI
Occupation
Electrician
Hello!
I have a client who is experiencing a slight tingling feeling when they stand on their deck and touch their hot tub water. The hot tub is controlled by a gfi breaker and is grounded by a EGC from the hot tub subpanel to the ground lug in the hot tub. Is there anything more that needs to be done? I am out of state and have to check it out next week so I told them to shut the breaker off and not use the hot tub. Has anyone ran into this problem and able to offer possible solutions to help me solve this? Thank you
 
Jpflex

Jpflex

Electrician big leagues
Location
Victorville
Occupation
Electrician commercial and residential
jraymond said:
Hello!
I have a client who is experiencing a slight tingling feeling when they stand on their deck and touch their hot tub water. The hot tub is controlled by a gfi breaker and is grounded by a EGC from the hot tub subpanel to the ground lug in the hot tub. Is there anything more that needs to be done? I am out of state and have to check it out next week so I told them to shut the breaker off and not use the hot tub. Has anyone ran into this problem and able to offer possible solutions to help me solve this? Thank you
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Yes I heard of this before and it may not even be so much the hot tub circuit but utility such as overhead high voltage power lines being grounded nearby causing possible voltage radiants on ground surface. Apparently this is hard to prove and utility are often reluctant to admit their nearby installs being a problem.

If the GFCI sees all power before the tub and and wood steps and if there were a difference in current between line and neutral I believe it should have tripped for a little as 4-6 mili amperes
 
H

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
The voltage may come from another source. The gfi only monitors leakage from only its source. Check for voltage from the deck with it being wet to the hot tub. Turn off breakers four or five at a time until the voltage is gone. Then narrow it down to which breaker removes the voltage. If none removes the voltage, it’s possible it’s a failing underground utility feed.
 
Jpflex

Jpflex

Electrician big leagues
Location
Victorville
Occupation
Electrician commercial and residential
hillbilly1 said:
The voltage may come from another source. The gfi only monitors leakage from only its source. Check for voltage from the deck with it being wet to the hot tub. Turn off breakers four or five at a time until the voltage is gone. Then narrow it down to which breaker removes the voltage. If none removes the voltage, it’s possible it’s a failing underground utility feed.
Click to expand...
That’s what I just said on previous post
 
W

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
Dennis Alwon said:
I would turn off the hot tub and see if you still feel a tingle then the issue is coming from the deck
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I would not advise anyone to attempt voltage measurements by the 'feel the tingle' method.

But I agree, the first measurement to take is water to deck with the breaker off. This might require the deck boards to be wet, or a large area electrode in contact with the wood.
 
H

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
winnie said:
I would not advise anyone to attempt voltage measurements by the 'feel the tingle' method.

But I agree, the first measurement to take is water to deck with the breaker off. This might require the deck boards to be wet, or a large area electrode in contact with the wood.
Click to expand...
When I was in tech school, we would go around with the maintenance guy to work on stuff at the school. He would wet his finger to test for voltage…….I think I will stick with the Biddle they let us use…..!
 
Speedskater

Speedskater

Senior Member
Location
Cleveland, Ohio
Occupation
retired broadcast, audio and industrial R&D engineering
Thinking about it further, while on a 6 mile walk.
A swapped Neutral and EGC somewhere in the circuit, could develop a few volts on the EGC when the tub's heater is operating.
 
kwired

kwired

Electron manager
Location
NE Nebraska
Occupation
EC
Miswiring or failing components is most likely going to trip the GFCI that should be required on this. So at very least make sure the GFCI is functioning.

My guess is we have a case of rise in potential in the service grounded conductor - a GFCI will not detect this either and is often the situation when we see electrocutions at boat docks and similar situations.

You have a little voltage between the EGC and true earth due to voltage drop on the service grounded conductor or even on utility's MGN. Unless there is a situation with your service neutral that is easily remedied chances are this is something you are not making go away. It may change at times as loads change but is beyond your control. Equipotential bonding is how you eliminate touch voltages in this situation.

A ground rod doesn't work. It only equalizes potential for a limited area in immediate vicinity of the rod.
 
tom baker

tom baker

First Chief Moderator & NEC Expert
Staff member
Location
Bremerton, Washington
Occupation
Master Electrician
Your solution may be to install a concrete pad with a copper wire inside to create an equal potential bond, connected to hot tub bond. Suggest getting a pool contractor involved. As pointed out it’s likely a utility issue, and most at the utility won’t understand it.
 
G

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
At this point you have no idea what the potential difference is between the water and the deck (which is very likely to be at local earth voltage. The high resistance of the connection to ground through the wood may be the reason you feel only a tingle rather than a jolt. If the voltage is high enough a better connection between you and local earth could well lead to a harmful shock rather than a mere tingle.
As several have recommended already, you need to take voltage measurements using a high impedance volt meter.
 
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