Got a number of GFI's installed for my lab's power needs. We keep popping the GFI's on a strip of outlets, mainly when we run centrifuges and an ice machine (both only pulling about an amp). The units run fine on non-GFI circuits, and they both check out OK when the electricians look for ground faults.

THe electrician says the GFI is doing it's job, and that they never go bad. THis is only one of 6 GFI's that serve the lab (all 20 or 30 amp GFI's embedded in the circuit breaker panel) that ever trips. I never have any problem with the other circuits, and we're running far greater loads on them. Is the electrician feeding me baloney or what? I'm not trying to bypass safety, just fix a persistant problem.

 

My son is a Union electrician, we built our own home with him doing the wiring and me learning/helping..............I also stayed at a Holiday Inn Express last night.

Don't mean to ask dumb questions but here it goes.........GFI's can be both at the receptacle/panel where AFI's. (arc fault) are at the panel. Since the popping circuits are at the panel are you sure they're GFI's or AFI's?

AFI's can be real sensitive to any spark.....even plugging and unplugging your devices.

GFI's are supposed to pop at moisture.

That being said..............yes, they go bad. Everytime a breaker pops, it loses a % of holding ability. If they have been popping a lot you need to replace 'em.

While building the house we had at least 3 breakers defective from the get go.

Not trying to downplay safety or an electricians worth but you can change a breaker in a matter of minutes. $10-$20 and you'll have an answer.

 

They do occasionally go bad, at least that is my experience as a homeowner and handyman(honey fix this).

Over time I think the springs in these things get relaxed or the "trigger" gets worn out and they will pop a little easier than when new.

I can only base this upon a guess and my training in electronics, I am NOT an electrician. I have had a couple GFI's over the years get to where they would pop if you looked at them. I replaced them and the problem went away, so I am convinced they do fail.

If it is not a faulty GFI then you do have a problem. A good GFI will pop when it senses a current over the threshold that I think returns to the ground line or neutral. THis usually happens when the appliance is bad. Or, I have had instances where a powercord sitting in water over time will soak thru and pop the GFI. If there is enough current flowing it could kill you, so the GFI is supposed to stop this before it happens.

Back in the old days when they didn't have grounded outlets or GFI, sometimes when you touched the steel handle on a faucet and some electrical appliance, you could get a good shock, sometimes enough to kill.

I would check that all the equipment is properly grounded and that none of the cords is worn out or sitting in water, like around a sink counter top. The cord may look OK but if it is wet it might conduct current where you don't want it. Also I noticed, if the cord was removed from the water, it would stop popping the GFI, so Like I said a cord can look good, but still have a problem.

Good Luck,

Jim Henderson

 

The breaker is a 20 amp GE breaker with GFCI. It's about 20 years old.

The power cords get checked once a quarter on every piece of gear in the lab. THe centrifuge pulls 1.8 amps and the ice machine pulls 3.7 A.

The electrician assigned to this work order is a BS artist who would rather argue for 2 hours than work for 10 minutes. Since most people (including me) aren't savvy enough electrical-wise, he's been getting away with this for 25 years. If this breaker pops again tomorrow, I will be seeing red.

 

Spikedog, if your equipment motors are of the double insulated type, they will trip a GFI. They lose and recover voltage that a GFI can't deal with and will trip often. This is one reason that you will find a non-GFI receptacle for a refrigerator in any kitchen or garage.

 

I'm not an electrician, but I'm in construction and have done plenty of my own wiring, along with quite a bit of research into electrical issues. Yes, GFIs go bad. Especially the early ones, both breakers and receptacles that are more than 10-15 years old.

A GFI works by sensing the current in the hot wire vs. the current in the neutral wire (think of it as "incoming" vs. "outgoing", but that's not really how alternating current works). Anyways, the two currents, under normal operating circumstances, should be identical. If they're different, that means that something else is providing a path to ground, potentially a soon-to-be dead person. The threshhold difference for a GFI to trip is something like 5 mA, so if the black (hot) wire is carrying 1.000 A and the white (neutral) wire is carrying 0.997 A, it won't trip. If that drops to 0.994 A, the GFI should trip. And, like I said, older stuff is known for nuisance trips, or flat-out failure.

Jason

 

> that they never go bad.

Lie 100%.

For my bosses rental houses, before the tenants moved in, I would go throughout the whole house and test every outlet with a dedicated GFCI tester. They do go bad, even if they do not trip.

 

A GFI will go bad and some will not even work. Don't even count on the little test button. A real life test is best for the first install. A tester is made specifically for the real life test. If the circuit fails, replace it. I know from experience. A bad GFI almost fried me with a power saw.

Also, a GFI will not work on a heavy surge curcuit (a/c, compressor).

 

Appears to be acid getting into the brushes of the motor for the centrifuge. GFIC off the hook for now.

 

not only do they go bad (totally fail or not protect) but they are notorious for kicking for no apparent reason (over sensitive and too quick to interrupt).

For this reason, be sure to never have a refridgerator, freezer, or other appliance that will cause a problem if it shuts off when you're not home on a GFI protected circuit.

 

yes GFCI's go bad, and any outlets downstream will show the same symptoms if wired in to that circuit. if you have a load that leaks amps or line voltage, you'll trip the bad one with the others following suit. if they are more than 5 yrs old replace all of 'em. make sure your load isn't overdoing the wiring. 14-2 15amp, 12-2 20 amp. good luck

 

I had a building full of little under counter ice machines that tripped the plug GFI's. I replaced the GFI's with Coopers (Brand) that I bought from Lowes. These have a little yellow trip light on them. I think the old ones were Leviton with the Black and Red buttons. A few of the Ice Machines still tripped their GFI's. These had pumps to pump the water out that went to the drain. I pulled the pumps out cleaned up the solderless connectors, plugged the connectors back in, and coated them with Liquid electric tape. I had no more problems after that. You may have to improve the insulation on the ice machine main pump, but I didn't have a problem with that.

 

When does the breaker trip, when the appliances turn on, off, or while they are running?