ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: 1 2 [3] 4   Go Down

Author Topic: Could this happen in a properly wired outlet?  (Read 1935 times)

Marc Sibilia

  • Newbie
  • *
  • Offline Offline
  • Posts: 11
Re: Could this happen in a properly wired outlet?
« Reply #20 on: September 29, 2017, 10:12:50 am »

That would not automatically trip the GFCI.

JR

The arc could have started from the hot to the neutral, but with the conductive plasma filling the area between the plug and the receptacle face, it is highly likely that some current sharing would occur to the ground pin, and that would trip the GFCI.
Logged

Dennis Wiggins

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 580
Re: Could this happen in a properly wired outlet?
« Reply #21 on: September 29, 2017, 08:37:11 pm »

My vote is a 2-prong appliance was plugged in, almost completely, and the tape measure brushed across the hot and neutral from the bottom side.
That would make a nice pffft. Bet you can't read the tape......
I don't believe the cover played a part at all.
Chris.

I'll second this... OK. I'll spill my beans.  I once 'cleverly' hung a key chain by its metal key ring around a counter top night light body (so I would always know where the key was).   ;)

Guess what happened a year later when I unplugged the nightlight to replace the bulb?  Exactly  as as shown in the picture. The exception being my cover plate was plastic.

-Dennis
« Last Edit: September 29, 2017, 08:49:21 pm by Dennis Wiggins »
Logged

Mike Sokol

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3050
  • Lead instructor for the No~Shock~Zone
    • No~Shock~Zone Electrical Safety
Re: Could this happen in a properly wired outlet?
« Reply #22 on: September 30, 2017, 10:48:30 am »

That would not automatically trip the GFCI.

JR

Yeah, a hot-to-neutral short won't trip the GFCI since there's no current imbalance. So a hot-to-ground short will trip it immediately once you get over 5mA current. And interestingly, a ground-to-neutral short can trip one since if you're on a branch circuit with a normal voltage drop on a neutral, you can get up to 3 or 4 volts between neutral and ground and still be within normal limits. So a short between the neutral and ground will create a fault current, and it's certainly enough to trip any GFCI due to the imbalance. 

John Roberts {JR}

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 15608
  • Hickory, Mississippi, USA
    • Resotune
Re: Could this happen in a properly wired outlet?
« Reply #23 on: September 30, 2017, 12:38:12 pm »

Yeah, a hot-to-neutral short won't trip the GFCI since there's no current imbalance. So a hot-to-ground short will trip it immediately once you get over 5mA current. And interestingly, a ground-to-neutral short can trip one since if you're on a branch circuit with a normal voltage drop on a neutral, you can get up to 3 or 4 volts between neutral and ground and still be within normal limits. So a short between the neutral and ground will create a fault current, and it's certainly enough to trip any GFCI due to the imbalance.
I just had another spurious GFCI trip on the GFCI outlet protecting my dishwasher and washing machine. This is a little awkward because the outlet for the dishwasher is out in the laundry room so I can't see the red light from inside my kitchen.

Connecting the dots, we had a power outage between when the GFCI outlet was last working and not, so apparently it tripped (or didn't set) when power was restored. I have several GFCI outlets around the house and only this one was affected by the power outage. This may be the second time this happened, but the first time I connected it to the power interruption.

JR

[edit- I had another spurious trip in the GFCI my dishwasher/washing machine is plugged into. This time it tripped while the washing machine was running. Since the washing machine is probably 20 YO, who knows? Finished the wash after being reset and didn't trip next time I did laundry. I am past due for new appliances but why fix it if it isn't broken. [/edit]   
« Last Edit: October 22, 2017, 04:30:42 pm by John Roberts {JR} »
Logged
On the internet people tell you everything "they" know, not the answer to "your" question.

Ken Cross

  • Newbie
  • *
  • Offline Offline
  • Posts: 21
Re: Could this happen in a properly wired outlet?
« Reply #24 on: October 22, 2017, 02:57:57 pm »

Assuming the GFCI was functioning properly, a hot-ground short should have tripped the GFCI-and typically these react at least 5-6 times faster than a circuit breaker. It would surprise me to see this much arcing from a GFCI protected fault-though I still find myself surprised quite often.

The tape measure senerio listed happened exactly that way in my garage a few years ago, and it was me who was holding the tape. Yes it was a GFI outlet and yes I had my band saw plugged in. the tape contacted the top of the band saw contacts. In my case (plastic box and cover) my hand on the tape and feet on the concrete floor tripped the GFCI. The result also looked the same. The GFCI saved me from feeling the shock. The arc still got my attention in a hurry.

Ken
Logged

Jeff Hague

  • Full Member
  • ***
  • Offline Offline
  • Posts: 154
    • Richmond Pro Audio
Re: Could this happen in a properly wired outlet?
« Reply #25 on: October 26, 2017, 04:11:49 pm »



We could lessen the likelihood of such accidents by simply installing receptacles upside down, so that the ground prong would be the first thing struck by a falling metal object. Surely I'm not the first one to realize this.

I see exactly this in a lot of new construction lately - the receptacles are "upside down". But it does make a lot of sense.
Jeff
Logged

Steve M Smith

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2976
  • Isle of Wight - England
Re: Could this happen in a properly wired outlet?
« Reply #26 on: October 27, 2017, 03:10:51 am »

We could lessen the likelihood of such accidents by simply installing receptacles upside down, so that the ground prong would be the first thing struck by a falling metal object. Surely I'm not the first one to realize this.

Or you could reduce it to zero by having safe plugs like we do in the UK.




Steve.
Logged

Jonathan Johnson

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2626
  • Southwest Washington (state, not DC)
Re: Could this happen in a properly wired outlet?
« Reply #27 on: October 27, 2017, 02:33:36 pm »

Or you could reduce it to zero by having safe plugs like we do in the UK.





Sure, but most AHJ would say "I'm not signing off; that's not the way we do it here."
Logged
Stop confusing the issue with facts and logic!

Mike Sokol

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3050
  • Lead instructor for the No~Shock~Zone
    • No~Shock~Zone Electrical Safety
Re: Could this happen in a properly wired outlet?
« Reply #28 on: October 27, 2017, 03:43:42 pm »

Sure, but most AHJ would say "I'm not signing off; that's not the way we do it here."

I've used a lot of Ceeform connectors in systems going out on international tours, and they makes hookup a lot easier and safer as well. But we're stuck with what we have here... :-[

frank kayser

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1098
  • Maryland suburbs of Washington DC
Re: Could this happen in a properly wired outlet?
« Reply #29 on: October 28, 2017, 09:48:49 pm »

I just had another spurious GFCI trip on the GFCI outlet protecting my dishwasher and washing machine. This is a little awkward because the outlet for the dishwasher is out in the laundry room so I can't see the red light from inside my kitchen.

Connecting the dots, we had a power outage between when the GFCI outlet was last working and not, so apparently it tripped (or didn't set) when power was restored. I have several GFCI outlets around the house and only this one was affected by the power outage. This may be the second time this happened, but the first time I connected it to the power interruption.

JR

[edit- I had another spurious trip in the GFCI my dishwasher/washing machine is plugged into. This time it tripped while the washing machine was running. Since the washing machine is probably 20 YO, who knows? Finished the wash after being reset and didn't trip next time I did laundry. I am past due for new appliances but why fix it if it isn't broken. [/edit]   


JR... Are you ever going to rewire that death trap of a house, or do you just like having a lab nearby?  ;)
Logged
Pages: 1 2 [3] 4   Go Up
 


Page created in 0.278 seconds with 18 queries.