GFCI nuisance trips with fluorescents?
i recently installed new lighting in my unfinished basement. one circuit with two groupings of lights, each grouping on its own three-way switches. the first grouping is (seven) recessed cans, all with compact fluorescents. the second grouping is (three) four-foot double-bulb T8 strip lights.
the first grouping (recessed cans) works fine.
the second grouping (strip lights) trips the breaker after 5-10 minutes of use. if i remove one of the tubes (so there are only 5 tubes burning instead of 6) it seems to work just fine. it does not seem to matter *which* bulb i remove, as long as i remove one of them.
i went through and checked the connections and they appear to be good. all components are brand new and i used what i think are high quality switches and strip lights. some searching here and on google indicated that fluorescents on GFCI can be problematic, but it is my understanding that GFCI is required for all accessible circuits in an unfinished basement.
any advice would be very much appreciated. thanks in advance.
Replies
Make sure the cases of the fixtures are grounded.
I don't believe that the GFCI is required if the circuit is dedicated to lighting, with no accessible outlets.
Sounds like there is very minor amount of leakage in the strip floursents. That is what EGC are for.
Rewire it so that they are not protected by the GFCI.
No CIRCUITS require GFCI protection. Only certain loads; receptacles in certain locations (such as unfinished basement) and places where you are in water with electrical connections (pools, hot tubs, and the like).
There are a few others such as bath fans over a shower, if the manufacture reqires it.
But in general lights don't need to be GFCI protected.
fixtures are definitely well grounded. i will just swap in a normal breaker. thanks for the help.
All of your receptical outlets in unfinished areas of the basement need to be GFCI protected. You can do this with GFCI recepticals and a normal breaker so the lights are not on the GFCI. There are exceptions to the GFCI rule: dedicated outlets for fridge, freezer, sump pump, security sys. or similar equipment so long as someone can't easily plug into an unprotected recep. without unpluging the equipment first. Those unprotected receps will ideally be behind the equipment.It is not my job to tell you that it can't be done. It's my job to tell you how much it will cost. Here, sign this change order.
thanks for the reply. the lights are on their own circuit. all receptacles in the basement are definitely GFCI protected. based on the information in "wiring a house" it sounded to me like lights also needed to be protected, but i obviously misunderstood what the author was saying.
Likely a bad fixture. Probably a ballast that has a small leak. Not uncommon in cheaper units like discount 'shop' lights. Replace the fixture is likely cheaper than replacing the ballast. Such ballasts usually fail after a few months use anyway as the leak becomes progressively larger. Usually not a major safety concern, as long as the internal thermal overloads function correctly. If not the dripping pitch, used in cheap units, is the least of your concerns.
Have also seen improperly stapled romex, or a screw used to mount the florescent fixture, show a similar fault behavior. A staple or screw going into the cable can cause leakage between the neutral and ground which will cause a GFI to trip. Easy enough to confirm this sort of thing by lifting, and isolating, the ground at the panel.
A hot to ground fault is also a possible cause but this sort tends to either progress to a real short, blowing the CB portion of the GFI breaker or blow clear which usually, but not always, cuts the power downstream of the fault and caused lights to be off.
A hot to neutral short wouldn't blow the GFI portion of the CB at all. It would look like a regular load to the GFI. Would blow the CB portion of the GFI breaker or any CB used in its place. Similar to the above short, blow clear or fail behavior explained above.
Localizing either or both faults down is a matter of splitting the circuit until the behavior goes away. A logical and step-by-step approach works best.