GFI outlet issues

[FOMOGO]

I have made a habit of never using push in outlet connections on outlets. They just always seemed iffy to me. And like RJ, 14 gauge for lighting only. Mike

 

[Tim9]

Throw away the GFCI when using a machine tool motor. At least that’s been my experience. Just make sure you lathe or mill is properly grounded. You should be fine.
Now mind you. Most licensed electricians aren’t going to throw away the GFCI for a customer that they don’t know. Too much liability. Can’t blame them.
12 gauge only for me. I follow code as best as I can. But I’ve been told by a number of electricians that the GFCIs are problematic. I make sure I don’t cut corners with electricity. And try to follow the codes...But, I may be a year or two behind. I’m sure in about 10 years.... maybe GFCIs may be more reliable. But until then...I don’t plug my big stuff into them. They and the arc-fault interrupters are problematic with big motors.
And totally agree. I don’t like the stab in connections.

 

[Todd727]

That's one I support. 14 gauge is too small in my opinion. This happened in my house, partly as a result of smaller wire. Load never tripped the 15A breaker. Measurements never got above 12A. The damaged plug was not in use, the heat came from the back as far as I can tell. I replaced the breaker as well to be on the safe side. A little extra copper costs less than a fire.

Looking at this again makes me want to swap all the 14 gauge circuits to 10A breakers, if I can find some..

I was happy to comply also. Best part is, I just put 20A breakers in throughout when I was building the house. The difference in overall cost for wires and breakers was less than $300.

 

[Todd727]

ARC Fault is even worse from what I've heard.

 

[NegativeK]

I've had this issue a couple of times. Most recently was with a Jet Wood Lathe my wife picked up with a variable speed drive. The solution for me has always been put a robust power strip in-between the device and the GFI protected circuit. Simple fix.

Can you elaborate? Is the power strip somehow filtering..?

I'd love to get 220V 50A service in the garage for tools and electric car charging, and I'd really rather not go down the rotary phase converter path (or worse -- an expensive isolation transformer). But we'll burn that bridge when we come to it.

 

[fursphere]

Can you elaborate? Is the power strip somehow filtering..?

I'd love to get 220V 50A service in the garage for tools and electric car charging, and I'd really rather not go down the rotary phase converter path (or worse -- an expensive isolation transformer). But we'll burn that bridge when we come to it.

Just a simple 110v power strip. Nothing fancy - has a built in breaker. For whatever reason it fixes the VFD tripping the GFI. Give it a try.

My new PM-30MV-HS has a 110v drive, and appears to get along with the GFIs in my garage. No issues so far.

 

[middle.road]

Just a simple 110v power strip. Nothing fancy - has a built in breaker. For whatever reason it fixes the VFD tripping the GFI. Give it a try.

My new PM-30MV-HS has a 110v drive, and appears to get along with the GFIs in my garage. No issues so far.

I would be leery of power strips. The last few I've taken apart used 'stab' in connections.
One 10A fried using a dremel on it.
A web search on 'fail power strip' will show more than you ever wanted to see.

 

[mksj]

The PM-30MV is a DC motor, at least on the current models, so should play better than VFD's. There are low leakage line filters that may mitigate some of the issues, such as the Shaffner FN3260 series, downside is they cost more than your VFD. I do use line filters on the incoming power to my VFD's and a toroid on the motor leads as well as shielding with star grounding. Problem is that there is no standard fix for grounding and stray current problems with VFDs. If you are running a 230VAC VFD, then until this year (per NEC) it would not require a GFCI, and if required it would compare both hot legs and not to neutral unless there was a 120 circuit. Usually the stray currents are in the neutral. Another misnomer is that GFCI is not an over current device, so it does not mitigate the need for a breaker. There are breakers with GFCI built in, but not sockets. Breakers use current vs. time curves to trip, and house wiring is only rated at 80% of the breaker amperage for continuous use.

 

[Tim9]

GFCI’s are just very problematic in my opinion. If I remember correctly, the old school method of running two 2 separate circuits using 12/3 or 10/3 wire was to share the common ground in the single Romex cable. Unfortunately with the newer codes in the 2000 years which dictates GFCIs, that method of saving time no longer works. 12/3 and 10/3 Romex is constantly tripping the GFCIS. MKSJ IS CORRECT. THEY SENSE THE GROUND.
Now, if you want to run GFCI’s it’s just better to run two separate Romex 12/2 or 10/2 cables. GFCIs do sense through the grounds. They are problematic. Yeah, they are great when using an outlet near a water source. I want them on those kitchen countertop outlets and bathroom outlets.
But no way would I waste my time with GFCI outlets in my workshop. I’d be spending my day walking back one forth to the electrical panels.

 

[vtcnc]

I'm not up to speed on NEC codes and the like, but I don't understand why there would be a code requirement for shop or garage outlets. It sounds like the requirement is possibly for outlets that are below grade - i.e. susceptible to flooding hazards. This would make sense to use GFCI but I can certainly understand why one would want to avoid nuisance tripping as well given the surges in current a GFI circuit would realize in your typical shop. With that said, I have my little HF Titanium 125 welder plugged into a 20A GFCI outlet in my garage coming off the subpanel. Zero nuisance tripping on that outlet.

I guess my big question is that a ground fault in a shop (outside of the disaster scenario of a flood) is likely going to trip the breaker regardless. I mean, GFCI as it is conventionally used is for safety around the moist/wet working environments. It seems silly to require GFCI on say a lathe circuit because the load is going to trip a regular breaker without a ground fault. Maybe I'm just not understanding but the GFCI is designed to provide personnel protection not equipment protection.

With that said, back in the day, I was a manufacturing engineer for an injection molding machine manufacturer. Our division built the control panels for the machines. The OSHA officer demanded that we provide ground fault protection for the final test assemblers while doing live, point-to-point testing in the cabinets. I was scratching my head for a few weeks - there wasn't any electrical supply contact in the area that even knew what I was talking about: 480V GFI personnel protection? It doesn't exist - I was told - good luck with your search.

I finally figured it out. The movie industry is required to provide 480V GFI protection for underwater filming. The lighting used in underwater shots - think JAWS - is 480V. Wasn't cheap, about $1500 per station, but we did it and it was the right thing to do. It actually was put to the test a few months later and I'm glad we had it in place.