GFI protection in greenhouse with heat mats tripping gfi

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FREEBALL

Senior Member
Location
york pa usa
Well I need help with the GFIs tripping when heat mats are plugged in to the gfis I know a few can be plugged in with no issues but there are now multiple plugged in and are tripping. the installation area (greenhouse) is kinda like a community commercial greenhouse and the area is divided into separate areas for each user. The heat mats they use, when a few are plugged in trip the gfi receptacles. what is the remedy for this more gfi circuits gfi breakers etc.

thanx jeff
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
That is why the rules in Article 427 for pipeline heat tracing specify the use of GFP (30mA trip) and not GFCIs (5mA trip). I don't know the details of your installation so I can't comment on what is required in your case.
 

iwire

Moderator
Staff member
Location
Massachusetts
I would put standard breakers in and install a GFCI receptacle at each location.

It sounds like a cumulative leakage current issue.
 

iwire

Moderator
Staff member
Location
Massachusetts
That is why the rules in Article 427 for pipeline heat tracing specify the use of GFP (30mA trip) and not GFCIs (5mA trip). I don't know the details of your installation so I can't comment on what is required in your case.

I am going to guess the circuits are general purpose receptacles that they are plugging the heat mats into.

The fact they are in a greenhouse necessitates GFCI.
 
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Fitzdrew516

Senior Member
Location
Cincinnati, OH
Sounds like a classic case of leakage current tripping the device. Did you install GFCI or GFP (30 ma)? For this application you're gonna want the 30ma trip to make sure you don't get the nuisance tripping of the standard 5ma.
 

FREEBALL

Senior Member
Location
york pa usa
that's the issue it is a cumulative issue the heat mats are on gfi devices. So a 30ma epd style breaker isn't allowed, so I believe, because the area is a wet area and anyone can unplug or plug in the heat mats this is for personell protection not equipment. So I guess the way to go is additional GFI recpts.
 

iwire

Moderator
Staff member
Location
Massachusetts
I believe, because the area is a wet area and anyone can unplug or plug in the heat mats this is for personell protection not equipment. So I guess the way to go is additional GFI recpts.

That would be my read on it.

FWIW some of our customers specify 'point of use' GFCI device as opposed to breakers for this very reason.
 

bphgravity

Senior Member
Location
Florida
Hopefully the branch circuit panelboard is relatively close (less than 250 ft) to the greenhouse. Capacitive coupling can be an issue for GFCI breakers with long circuit runs.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
I am going to guess the circuits are general purpose receptacles that they are plugging the heat mats into.

The fact they are in a greenhouse necessitates GFCI.
If they are plug-in heat mats I would agree that you have to have GFCI protection for the receptacles as the area would be a wet location.
 
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