Any ideas about why bathroom exhaust fan in shower trips GFCI outlet

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mrtom

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Chicago-Area
Had a service call the other day in which a homeowner showed me a standard Broan combination exhaust fan/light that he installed himself directly over the tub (something I think is a bad idea/design). To make matters worse, there is a soffit over the tub which brings the fan combo (and ceiling) just about 6" higher than the showerhead. I was told the bathroom counter-top GFCI feeds the fan combo and that it trips atleast once a week only while exhaust fan is running.

I confirmed all wiring was done correctly and GFCI outlet was working correctly. I advised that the problem could be a nuisance trip due to exhaust fan motor OR since exhaust fan is directly in shower area with such a low soffit that maybe steam/moisture from a hot shower was somehow effecting motor and therefore the GFCI.

Anybody else ever deal with something like this? I was going to change GFCI outlet and wait to see if the problem stops before having owner purchase an exhaust fan rated for a steam room or something similar.

Thank you in advance for any ideas!
 
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gar

Senior Member
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Ann Arbor, Michigan
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EE
140429-1451 EDT

mrtom:

It is very important to determine if tripping only occurs when the fan or light are on. This means that the tripping never occurs at turn on or turn off.

If tripping is only during the on state, then I would agree the likely cause is related to moisture and other contaminants.

.
 
qcroanoke

qcroanoke

Sometimes I don't know if I'm the boxer or the bag
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Sorta retired........
mrtom said:
Had a service call the other day in which a homeowner showed me a standard Broan combination exhaust fan/light that he installed himself directly over the tub (something I think is a bad idea/design). To make matters worse, there is a soffit over the tub which brings the fan combo (and ceiling) just about 6" higher than the showerhead. I was told the bathroom counter-top GFCI feeds the fan combo and that it trips atleast once a week only while exhaust fan is running.

I confirmed all wiring was done correctly and GFCI outlet was working correctly. I advised that the problem could be a nuisance trip due to exhaust fan motor OR since exhaust fan is directly in shower area with such a low soffit that maybe steam/moisture from a hot shower was somehow effecting motor and therefore the GFCI.

Anybody else ever deal with something like this? I was going to change GFCI outlet and wait to see if the problem stops before having owner purchase an exhaust fan rated for a steam room or something similar.

Thank you in advance for any ideas!
Click to expand...

Most everyone in here will tell you that the GFI tripped because the fan has a problem.
But I think that fan is too close also.
 
M

mrtom

Member
Location
Chicago-Area
gar said:
140429-1451 EDT

mrtom:

It is very important to determine if tripping only occurs when the fan or light are on. This means that the tripping never occurs at turn on or turn off.

If tripping is only during the on state, then I would agree the likely cause is related to moisture and other contaminants.

.
Click to expand...

Yes, the GFCI only trips when the exhaust fan is running, and I can only guess that since it is directly in the shower area that the fan is only on while someone is taking a shower. Steam and/or moisture getting into the motor somehow was the only problem I could think of.
 
Pharon

Pharon

Senior Member
Location
MA
Maybe I'm missing something, but can't you just connect the motor to the line side of the GFCI recep? That would eliminate the nuisance trips, no?
 
Barbqranch

Barbqranch

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Location
Arcata, CA
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Plant maintenance electrician Semi-retired
Many of these fans use a plug and socket to simplify removing the motor and blades from the housing. It might be possible to clean the plug and outlet and maybe apply something to keep water out of there. That seems to me to be the most likely place to create a ground fault.

Yes, I do agree it should be removed or replaced w/ one designed for that type of location.
 
M

mrtom

Member
Location
Chicago-Area
Pharon said:
Maybe I'm missing something, but can't you just connect the motor to the line side of the GFCI recep? That would eliminate the nuisance trips, no?
Click to expand...

Oops, I forgot to mention that the owner wants the GFCI protection to remain. I was just double-checking what I told him about the standard fan being in a bad location and steam/moisture/water maybe going into fan and causing the trip.
 
H

h1h2h3

Member
Location
MA
Pharon said:
Did you tell him that GFCI is only required (and necessary) for the receptacle?
Click to expand...

You are correct about that. However, the NEC is a minimum. If a homeowner is going to be standing in a tub/shower area that contains water and bonded water pipes, it may not be the worst idea in the world to keep the GFCI protection...from a safety standpoint and not necessarily a convenience standpoint. However, what if the recs inside of the fan combo were within 6' (in any direction) of the bathroom sink, would GFCI protection be required then?
 
Besoeker

Besoeker

Senior Member
Location
UK
Pharon said:
Maybe I'm missing something, but can't you just connect the motor to the line side of the GFCI recep? That would eliminate the nuisance trips, no?
Click to expand...
I can't comment on code compliance but that seems to me a bad idea.
Think about what GFCI stands for. If there is a detectable ground fault I'd want the circuit to be interrupted.
In any circumstances but especially so if I'm soaking wet.
 
kwired

kwired

Electron manager
Location
NE Nebraska
These fans are also supposed to be designed for damp locations. I will still say something is possibly wrong with the fan, or possibly you have a nicked conductor insulation and it is close to the grounded enclosure of the unit, a little moisture gets in there and there is enough leakage to trip the GFCI. This leakage could be on the ungrounded or grounded conductor as well.

I would meg the thing, if it tests good run the shower and steam the room up a little and meg it again. Go back to the load side of GFCI and test from there, so you are checking everything protected by the GFCI. Disconnect both grounded and ungrounded conductors - you don't want to read any continuity from the grounded conductor to the EGC that comes via the bonding jumper back at the service.

You may even find the problem is not the fan, but maybe a skinned conductor in the switch box or something like that.
 
mopowr steve

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
Sierrasparky said:
Not necessarily ture, most fan manufactures require a GFCI if installed over a tub.
Click to expand...

I agree do not remove it from the GFI is is required when fan/ or fixtures are located in the shower space.
I have had issue some time ago with exhaust fans tripping the bathroom GFI the moment the fan is turned OFF I think due to outrush current when the magnetic field of fan motor collapses.
 
kwired

kwired

Electron manager
Location
NE Nebraska
mopowr steve said:
I agree do not remove it from the GFI is is required when fan/ or fixtures are located in the shower space.
I have had issue some time ago with exhaust fans tripping the bathroom GFI the moment the fan is turned OFF I think due to outrush current when the magnetic field of fan motor collapses.
Click to expand...
That would be because of inductive kickback. Best solution to that problem is not to buy the cheap no name GFCI's at the big box stores.
 
M

mrtom

Member
Location
Chicago-Area
Thank you for all the input and ideas. I plan on leaving the fan with GFCI protection, change the brand of the GFCI outlet, and rewire to the exhaust fan (it is in 1/2" emt and will take 5 minutes to do). If issue still happens, then the problem should be the exhaust fan and will be replaced.
 
kwired

kwired

Electron manager
Location
NE Nebraska
mrtom said:
Thank you for all the input and ideas. I plan on leaving the fan with GFCI protection, change the brand of the GFCI outlet, and rewire to the exhaust fan (it is in 1/2" emt and will take 5 minutes to do). If issue still happens, then the problem should be the exhaust fan and will be replaced.
Click to expand...

A megger test is more likely to find the problem the first time and make you look smarter for finding it the first time:happyyes:

Or you could be lucky and replace that conductor with the bad spot or replace the defective GFCI without really knowing it is defective and still fix the problem the first time.
 
T

Toros

Senior Member
Location
Tujunga, CA
mrtom said:
Had a service call the other day in which a homeowner showed me a standard Broan combination exhaust fan/light that he installed himself directly over the tub (something I think is a bad idea/design). To make matters worse, there is a soffit over the tub which brings the fan combo (and ceiling) just about 6" higher than the showerhead. I was told the bathroom counter-top GFCI feeds the fan combo and that it trips atleast once a week only while exhaust fan is running.

I confirmed all wiring was done correctly and GFCI outlet was working correctly. I advised that the problem could be a nuisance trip due to exhaust fan motor OR since exhaust fan is directly in shower area with such a low soffit that maybe steam/moisture from a hot shower was somehow effecting motor and therefore the GFCI.

Anybody else ever deal with something like this? I was going to change GFCI outlet and wait to see if the problem stops before having owner purchase an exhaust fan rated for a steam room or something similar.

Thank you in advance for any ideas!
Click to expand...
relocate the fan circuit from load side of GCFI to the line side same, with nutral conductor
 
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