hot tub problem

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sd4524

Senior Member
Location
Southern California
I looked at a job yesterday at a rental house for a property manager. Tenants say that if they stand barefoot in backyard and put hand in hot tub they get a shock. When they turn the main breaker off then they don?t get a shock. This started about a month ago right after an old hvac unit was removed from under the house. I checked all of the hot tub wiring (new) and it was done properly, connections were tight, voltages o.k., bonding of motor, h20 pipes done right. I megg?d the wiring from panel to disco and the wiring from disco to hot tub- no problems.
I checked the voltage at main panel and had 120 to ground on both L1 and L2 and 240 between L1 and L2 with all ckt?s turned on. # 4 ground wire goes under house and I was unable to determine what it goes to. There are quite a few mwbc?s and the only other 240v load is an oven. I went under the house briefly and it was a complete abortion- wires lying on ground, open j boxes, open splices, some k and t, some romex, some old bx, the 240 oven (#6) is splices in a j box that?s too small. Still couldn?t see where the main ground wire went to. It eventually got too dark to see so I told them I would be back early next week.
Here is my plan:
1. Install ground rod and bond to water pipes if not already done.
2. Pull meter and check for loose neutral, check overhead utility connections
3. check all mwbc connections
I?m thinking that when old hvac unit was removed from under the house maybe a connection was damaged.
Besides sticking my hand in the tub with no shoes on what is a good way to test if problem is gone? Any other suggestions? What is most common cause of this problem? If I call sdg&e I want to be sure that I have check'd everything possible first.
 
H

hillbilly

Senior Member
sd4524 said:
I looked at a job yesterday at a rental house for a property manager. Tenants say that if they stand barefoot in backyard and put hand in hot tub they get a shock. When they turn the main breaker off then they don?t get a shock. This started about a month ago right after an old hvac unit was removed from under the house. I checked all of the hot tub wiring (new) and it was done properly, connections were tight, voltages o.k., bonding of motor, h20 pipes done right. I megg?d the wiring from panel to disco and the wiring from disco to hot tub- no problems.
I checked the voltage at main panel and had 120 to ground on both L1 and L2 and 240 between L1 and L2 with all ckt?s turned on. # 4 ground wire goes under house and I was unable to determine what it goes to. There are quite a few mwbc?s and the only other 240v load is an oven. I went under the house briefly and it was a complete abortion- wires lying on ground, open j boxes, open splices, some k and t, some romex, some old bx, the 240 oven (#6) is splices in a j box that?s too small. Still couldn?t see where the main ground wire went to. It eventually got too dark to see so I told them I would be back early next week.
Here is my plan:
1. Install ground rod and bond to water pipes if not already done.
2. Pull meter and check for loose neutral, check overhead utility connections
3. check all mwbc connections
I?m thinking that when old hvac unit was removed from under the house maybe a connection was damaged.
Besides sticking my hand in the tub with no shoes on what is a good way to test if problem is gone? Any other suggestions? What is most common cause of this problem? If I call sdg&e I want to be sure that I have check'd everything possible first.
Click to expand...


Sounds like you've got voltage on the Hot tub grounding conductor.
Could be because of a open service ground, and voltage is returning thru the grounding wire (all available paths).
I would also check the bonding in the main panel.

You say that this tub is 240V?
Any 120V loads in the tub?
If so, did the installer run a 4 wire circuit to the tub?
If 4 wire, check for voltage between the grounding and grounded (neutral) conductor.

If it's a 3 wire circuit and he's using the grounding conductor as the neutral, it could cause this problem.

Is the circuit GFI protected?

Just a few ideas
steve
 
2

220/221

Senior Member
Location
AZ
A ground rod may disguise the problem but won't fix it.

1) You need to be able to read the voltage. One probe in the water, one to ground may read it. A non contact tester may read it.

2) Turn off circuits one at a time to try and narrow down the source.

Smart money is on an open neutral somewhere.

Electrons are on a mission and they take interesting paths to get to where they are trying to go. If there is a door blocked somewhere they will take another route if available.
 
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K

Karl H

Senior Member
Location
San Diego,CA
It sounds like the Hot Tub supply isn't protected by a GFCI
disconnect.If it was, the GFCI would have opened the circuit
as current is travelling on the grounding conductor.That
is IF all the water pipes are bonded properly.
 
2

220/221

Senior Member
Location
AZ
Not necessarily. If the current is flowing, the lights are working.

Problem is, the current is flowing where it shouldn't be.


Problem isn't necessarily with the hot tub circuit. It is just showing there.
 
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sd4524

Senior Member
Location
Southern California
Hot tub is supplied by 4 wires and is in fact gfi protected. Tenants said that gfi never tripped. Based on what Karl H says then the water pipe isn't bonded properly.
Never thought of using my digital meter with one probe in the water. Thanks for the idea.
If there is voltage between water and ground wire then I will test ckts one at a time and see if voltage is only present with one particular ckt on.
 
ceb58

ceb58

Senior Member
Location
Raeford, NC
[
quote=sd4524;984805]I looked at a job yesterday at a rental house for a property manager. Tenants say that if they stand barefoot in backyard and put hand in hot tub they get a shock. When they turn the main breaker off then they don?t get a shock. This started about a month ago right after an old hvac unit was removed from under the house.

There are quite a few mwbc?s and the only other 240v load is an oven. I went under the house briefly and it was a complete abortion- wires lying on ground, open j boxes, open splices, some k and t, some romex, some old bx, the 240 oven (#6) is splices in a j box that?s too small
Click to expand...

[/QUOTE]

The area the hvac unit was removed is the place to look. The water pipe bond may have been knocked off if there was one or they have a ungrounded conductor damaged and is sending power through the ground.
Be careful if you go crawling back under the house you may find an energized water line.It would not be nice laying on the ground to get into it:mad:
 
J

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
Your previous post said you measured voltages L-L and L-G. You also need to measure L-N and N-G at the service and at the tub. Do not assume neutral and ground are connected together - verify it.
 
quogueelectric

quogueelectric

Senior Member
Location
new york
Also press the test button on the gfci to verify it works. This may be stray voltage from the ground finding its way to the good/better tub ground but if the shock goes away when the breaker is shut off it is probably coming from the tub.
 
kbsparky

kbsparky

Senior Member
Location
Delmarva, USA
WE had a similar problem in a multi-unit project in Ocean City. Traced the problem to a bad compressor motor in an old A/C unit. The other problem was the main bonding jumper was missing in the main meter stack/service panel.

When that compressor kicked in, it literally energized all the EGC's in the building, including all the hot tubs sitting outside. Anyone getting into or out of a tub during that time would get zapped. Even if you tripped out the GFI protecting the individual tubs, you would still get zapped. Thing is, the GFI's don't disconnect the EGC from the circuit, so any potential difference there is still felt. Replacing the GFCI won't solve anything if your EGC is the problem.

Once we fixed the main bonding jumper problem, the next time that A/C unit tried to start, it blew it's own breaker as it should have in the first place.

While this experience was unique, any loose connection(s) on your main EGC or neutrals may cause similar symptoms ... :confused:
 
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