Recipe for Death:

Status
Not open for further replies.
R

rattus

Senior Member
I have heard of plumbers meeting their maker while working under a house, on wet ground, with sweaty clothes, and using an ungrounded, metal cased power tool. Sometimes the tool might have an EGC, but they, like many other tradesmen, might cut off the grounding prong, or use a 2-wire extension cord, or a faulty 3-wire cord.

Thank whatever gods there be for double insulated and battery powered drills, etc.
 
charlie b

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Semi-Retired Electrical Engineer
Re: Recipe for Death:

If they were to plug the tool into a GFI-protected outlet, they would experience no more than the nuisance of having the power go off. My old house does not have any outside outlets. But if I need power outside, I run an extension cord out a bathroom window, and use the bathroom's GFI outlet.
 
C

charlie tuna

Senior Member
Location
Florida
Re: Recipe for Death:

someone in dade county was killed last week while setting up christmas yard lights --- it had just finished raining and he was bare-footed!
 
R

rattus

Senior Member
Re: Recipe for Death:

Charlie B., I have rigged up a GFCI in a box with a short power cord on it for situations such as this. It is my understanding that the EGC is not required for the GFCI to work. Right? Or, am I dead wrong? Pardon the pun.
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Re: Recipe for Death:

Originally posted by rattus:
I have rigged up a GFCI in a box with a short power cord on it for situations such as this.
Click to expand...
Your thinking about safety but your cobbling stuff together. :roll:

There is no way to make what you describe in a code complaint manner.

Ready made UL listed GFCI cord sets are available.

Also the listing requirements for these portable GFCI cord sets are even tougher than for wall mount GFCI receptacles.

Throw out what you made go to an electrical supply house and buy the right equipment.

[ December 02, 2004, 06:44 PM: Message edited by: iwire ]
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Re: Recipe for Death:

Here are a couple of types

PORTABLE 18-INCH GFCI Price $37.99

4274.jpg


This one just plugs into an outlet and you plug your own cord into this.

GFCI OUTLET ADAPTER Price $18.99

4275.jpg
 
dereckbc

dereckbc

Moderator
Staff member
Location
Plano, TX
Re: Recipe for Death:

Originally posted by rattus:
It is my understanding that the EGC is not required for the GFCI to work. Right? Or, am I dead wrong? Pardon the pun.
Click to expand...
You are right, but keep in mind a GFCI will not prevent a shock, only limits the amount of time of the shock.

Edited for clarification.

[ December 02, 2004, 06:46 PM: Message edited by: dereckbc ]
 
R

rattus

Senior Member
Re: Recipe for Death:

iwire, nice little gizmo, and if I were a pro, I would have one, maybe two. But I don't see that my little homemade job is any less safe than the pretty one. Sure it is probably not code compliant, but it works the same way. I have tested it by simulating a fault with a resistor.

Yep, I understand getting a pretty good shock. Worst I ever had was 300Vdc from a juke box amp. Made me woozy. And, I have a pair of pliers that used to be needle nosed.

[ December 02, 2004, 06:55 PM: Message edited by: rattus ]
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Re: Recipe for Death:

rattus,
Sure it is probably not code compliant, but it works the same way.
Click to expand...
No, it doesn't work the same way and it is less safe. Portable GFCI's are required to have open neutral protection, the one that you made does not have this protection. If the neutral on the line side of the GFCI is open and at the same time you have a ground fault on the load side you have no protection. Open neutral protection kills the power to the GFCI recp any time there is no power on the line side. That is why you have to reset portable GFCIs each time you plug them in. Note that open neutral protection has been required for 10 to 12 years, so if you have an older portable GFCI it will not have this protection.
Don
 
R

rattus

Senior Member
Re: Recipe for Death:

Don, I did not know that! If you want to know something, ask a pro. One could easily lose the neutral by plugging into an aged receptacle. Extension cords are even worse. But, if my box mounted GFCI had open neutral protection, it would be safe.
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Re: Recipe for Death:

rattus,
Yes, if you add a relay on the line side of the GFCI you can provide the same protection. The hot and neutral feed a set of NO contacts and the coil of the relay. The other side of the contacts feed the GFCI. Now when you lose the neutral, the power to the GFCI is cut off.
Don
 
T

templdl

Senior Member
Location
Wisconsin
Re: Recipe for Death:

I have always believed that one should never intentionally overload a circuit knowing that the beaker will trip and one would intentionally use a portable electric tool such as the one described relying of a GFCI to protect you from an electric shock.
You would like overcurrent protect when a circuit is unintentionally overloaded and should there be an unexpected failure of a portable electric tool or similar device.
One should never put themselves in harms way by intentionally depending upon these devices for protection. Russian roulette.
 
R

rattus

Senior Member
Re: Recipe for Death:

Don, before I would wire up a relay, I would go out and buy one of the portable jobs. Fellow name of Henry Goldwasser has an interesting piece on GFCIs (on the web). He talks of neutral to ground faults, but nothing of open neutrals. It seems that some of these units have ICs and power supplies built in, but I surmise that the simpler units use only magnetics to trip a switch which is not a circuit breaker in the usual sense.
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Re: Recipe for Death:

rattus,
All GFCIs have electronics to operate the trip and they are not fail safe. That is, if the electronics fail, you have no GFCI protection. Even the new "lock-out" types are not fail safe. If you test them and the electronics don't work, then you can't reset them, but if the electronics fail while the GFCI is in use, then you have no protection. As far as neutral to ground faults, if this occurs on the load side of the GFCI, then the GFCI will trip. Also the GFCI does not provide any overcurrent protection for the circuit or equipment, that is the job of the circuit breaker or fuse.
Don
Don
 
R

rattus

Senior Member
Re: Recipe for Death:

Don, I suspected that there might be some electronics involved because sensing a few mA out of several Amps is a tricky business. Reminds of the time about 40 years ago when the Jacuzzi people asked Texas Instruments to design a protective circuit for them. Xitters were not so reliable then, so we politely declined.
 
R

rattus

Senior Member
Re: Recipe for Death:

Gents, the inner workings of the GFCI are quite interesting. Now if I plug in my standard GFCI to a solid outlet, and if I plug my 3-prong tester into the GFCI to detect an open neutral, then I would be pretty safe. Don't worry, I hardly use the thing at all, and if I crawl under the house, I will obtain the proper equipment, and I would use either double insulated or battery powered tools anyway. Thanks for the education.
 
Status
Not open for further replies.
Top