Does a GFI actually trip on over current?

[toypusher]

.............................

Yup, often it's a direct short to arm or leg.....

Andrew

[bobhenry]

Thanks everyone. I was one of those that thought that a GFI would trip in the case of an overload. You set me straight.

Dan : I still am not convinced that the gfi alone will not protect my trailer,. Why are they rated at 15 and or 20 amps if they can not detect an overload ?

I direct shorted my wiring while wiring up my tear and it tripped from the direct short. However I have not tried hooking up the coffee pot, crock pot ,microwave ,and a space heater on the same circuit to see if I can melt down the wiring either !

[Kevin A]

Thanks everyone. I was one of those that thought that a GFI would trip in the case of an overload. You set me straight.

Dan : I still am not convinced that the gfi alone will not protect my trailer,. Why are they rated at 15 and or 20 amps if they can not detect an overload ?

I direct shorted my wiring while wiring up my tear and it tripped from the direct short. However I have not tried hooking up the coffee pot, crock pot ,microwave ,and a space heater on the same circuit to see if I can melt down the wiring either !

Bob,
Standard power outlets are rated at 15/20 amps as well, but we both know they won't protect your circuits from overload. They have that rating so we will know not to load that circuit with a load greater than what that circuit can handle. Why take the chance with an electrical fire in your trailer? Install the appropriate fuse/circuit breaker.
Bottom line, GFCI's were designed to protect you from being shocked, fuses and circuit breakers are there to protect an electrical circuit from overload.

[madjack]

...besides, for less than 3 bucks, you can purchase a sweet little push button, panel mount circuit breaker from www.waytekwire.com ...they are about the size of a matchbook and come in various amp ratings...
madjack

[jeep_bluetj]

Dan : I still am not convinced that the gfi alone will not protect my trailer,. Why are they rated at 15 and or 20 amps if they can not detect an overload ?

'Cause that's the current limit that they can handle before they burst into flames. No, your GFI likely won't flambeau at 21A, but I betcha it will at 50, right along with your wiring. Bursting into flames is not acceptable to most folks as a fuse.

I direct shorted my wiring while wiring up my tear and it tripped from the direct short. However I have not tried hooking up the coffee pot, crock pot ,microwave ,and a space heater on the same circuit to see if I can melt down the wiring either !

It tripped because some current went somewhere else. If you shorted hot to neutral it may have tripped due to the massive instant inductive load you put on it (the wire). Shorted to something resembling ground -- well that's the definition of ground fault.

Plug 5 coffepots in, and it won't trip. I guarantee it. You'll be able to keep the coffee hot with the wire too.. It's gonna get nice and warm.. (Until something blows up)

[Nitetimes]

Plug 5 coffepots in, and it won't trip. I guarantee it. You'll be able to keep the coffee hot with the wire too.. It's gonna get nice and warm.. (Until something blows up)

I wouldn't be so fast to be making guarantees... I have tripped quite a few of them with power tools, particularly circular saws. It can be done without causing other damage to wiring or itself. I have done it to new ones as well as older ones. This isn't their intended purpose but it will happen, generally on start up. I've pretty much quit using them for any outdoor receptacles I intend to run tools off of because of that.

[jeep_bluetj]

Qualified guarantee? Guaranteeed for all non inductive or capacitive loads?


GFI nuciance trips due to inductive loads are common. It's one reason why the NEC requires GFI for kitchen countertop outlets, but not for the fridge outlet.

GFIs nuciance trip because some of the current DOES 'dissapear' for awhile: it's essentially being converted to a magnetic field/being stored in a capacitor (depending on motor type). So amps out doesn't equal amps in, and a gfi may trip.

I'd just reset the GFI, rather than being outside with a electical device in my hand standing on a really good ground. But then again, I think that GFIs are the best electrical safety device since insulation.

Or get new GFI's. I used the top-notch medical grade ones in my garage and the thing NEVER nuciance trips. Pops every time the sprinkliers hit the Christmas lights though. And it's tripped every time I've cut a cord in half too.

Mechanical stress (being jammed tightly in the box) can also make them more or less sensitive. I've replaced a few that just would never reset because they were bent in the middle. (HD cheapies)

[alabubba]

What Kevin said. They are to protect you, not the hardware. Yes they sometimes can trip for no apparent problem, but I'll gladly accept that minor inconvenience for the extra safety they provide. By design, they should trip before you experience a lethal current. Remember that 110 can "freeze" you to the voltage source so you can't let go, whereas at higher voltages you tend to burn off the circuit prior to death.

[bravebear]

I overloaded my GFI and it tripped. I pluged a 12volt appliance in to it.
It tripped. I unplugged reset and all was fine. May be more to it than I know about. I would still use a fuse on the circuit.

[eamarquardt]

I agree that:

1) GFIs are not fuses or circuit breakers
2) Cutting off the ground lead on a tool will not affect the operation of a GFI (as described on CSI TV show)
3) Loads that are reactive (cap. or inductive) will cause false trips (based upon my personal experience and a converstation with Leviton (sp) when I had trouble with a reefer on a GFI). This is due to the phase shifting effect (voltage versus current) of reactive loads.
4) The "insurance" of a GFI greatly outweighs (in my mind) the inconvenience of an occasional false trip. If a GFI trips repeatedly, replace it and/or have the offending device checked at a tool repair shop.

There is sometimes a lot of misinformation in these posts and this, at times, may lead people astray. I encourage everyone to keep an open mind, research topics on the net, and not believe everthing you hear or read.

Cheers,

Gus

[Chuck Craven]

Well I don’t know if I should jump in or not. But I guess I can’t stop my self!!!

First off all power outlets, switches, light bulb sockets and all electrical devices have to be rated for the maximum current that device can safely handle. This goes for GFI outlets. Circuit breakers are rated for the maximum current the device will allow to pass through it. Which means it will trip at some current above its rated current.
Now what is bothering me about this thread is the word (GROUND). That green wire is not GROUND it is a safety ground wire. It is to supply a safety ground to each electrical device on that electrical circuit. You can’t depend on the thin wall tubing or BX cable to give you a safety ground when it may have a loose mechanical connection some place. Some cords have three wire plugs that will bring the safety ground to that device like your computer, TV may or may not have a three wire plug and your lamp most likely will not have a safety ground. That is up to the manufacture to provide. If your table lamp has a 100-watt light bulb in it does it have a fuse or a breaker in it too? NO! Your camper is just like your table lamp, as the electrical code goes. But there is no law that you can’t put in a breaker / fuse box for your own piece of mind. If your camper is wired for 15 amps or 20 amps why are you plugging it in to a 30 amp circuit?
In the Benroy build document the GFI outlet to be installed as the first outlet is for your protection. It is not needed. If you camp at an old Ma and Pop camp ground the power pole may not have GFI protection. Also if you plug in your tear into an outside or garage outlet, in a house that was built before mid 1980’s a GFI protected outlet was not required. Ask your self do you want to stand in a water puddle and toast some bread in that two wire old toaster with out some type of GFI protection? AS for pounding in a ground rod and connecting your tear to it, you have to be NUTS! Ask your self what is under the surface of the ground you plain on pounding that ground rod into. GAS line, POWER feeder for the campground, may be a oil pipe line. If it’s the power feeder for the campground, that could be fused at 1000 or more amps and if you hit that with your ground rod, POOF no more you….
Ground rods are used to bleed off static electricity from devices in electrical storms.
That is its only purpose and not your TEAR! If lighting directly hits and electrical device the GROUND ROD does nothing!!!! A #14 or #12 wire is just a carbon track to 1,000,000 + volts at 1,000,000 + amps for 1/100th of a second.



Chuck

[eamarquardt]

..........(1) Circuit breakers are rated for the maximum current the device will allow to pass through it. Which means it will trip at some current above its rated current.(2)Now what is bothering me about this thread is the word (GROUND). That green wire is not GROUND it is a safety ground wire. It is to supply a safety ground to each electrical device on that electrical circuit. (3)You can’t depend on the thin wall tubing or BX cable to give you a safety ground when it may have a loose mechanical connection some place. (4)Some cords have three wire plugs that will bring the safety ground to that device like your computer, TV may or may not have a three wire plug and your lamp most likely will not have a safety ground. (5)That is up to the manufacture to provide. If your table lamp has a 100-watt light bulb in it does it have a fuse or a breaker in it too? NO! Your camper is just like your table lamp, as the electrical code goes. But there is no law that you can’t put in a breaker / fuse box for your own piece of mind. If your camper is wired for 15 amps or 20 amps why are you plugging it in to a 30 amp circuit?
(6)In the Benroy build document the GFI outlet to be installed as the first outlet is for your protection. It is not needed. If you camp at an old Ma and Pop camp ground the power pole may not have GFI protection. (7)Also if you plug in your tear into an outside or garage outlet, in a house that was built before mid 1980’s a GFI protected outlet was not required. Ask your self do you want to stand in a water puddle and toast some bread in that two wire old toaster with out some type of GFI protection? (8)AS for pounding in a ground rod and connecting your tear to it, you have to be NUTS! Ask your self what is under the surface of the ground you plain on pounding that ground rod into. GAS line, POWER feeder for the campground, may be a oil pipe line. If it’s the power feeder for the campground, that could be fused at 1000 or more amps and if you hit that with your ground rod, POOF no more you….
(9)Ground rods are used to bleed off static electricity from devices in electrical storms.(10)That is its only purpose and not your TEAR! If lighting directly hits and electrical device the GROUND ROD does nothing!!!! A #14 or #12 wire is just a carbon track to 1,000,000 + volts at 1,000,000 + amps for 1/100th of a second.

:dead:

Chuck

Wow you just said/wrote a lot. Some of which I agree with some of which I do not. I have deleted some stuff to keep this as short as possible and if you feel I have quoted you out of context, my appologies. I have added numbers in (*) to connect our thoughts.

(1) I agree
(2) There are three "colors" of wire in a typical circuit. Black which is hot and carries current in the cicuit during normal operation. White which is neutral and carries current to ground (as in the earth)during normal operation . There is green which is for safety purposes, is connected to ground (as in earth) and should not, during normal circuit operation, carry any current. The ground lead (green) is typically connected to the metal housing of a tool, the white (even though they end up at the same place (earth) is not.
(3) I agree
(4) I agree
(5) I agree
(6) I don't know if it's needed or not (to meet a code requirements where ever you happen to be) but it's a nice thing to have in the circuit and I would include it in any teardrop design for the protection and peace of mind it provides.
(7) I agree
(8) Not likely, but I agree.
(9) Ground rods may serve that function but that is definately not their only function.
(10) One important function of the ground rod is to conduct the neural wire back to ground (earth) so that the electrons can flow back and forth to the power company. Here in the USA we use the earth as a conductor. I don't think this is the case everyplace in the world, but it is here in the USA. The green wire goes to exactly the same place (look in your breaker box) to the ground rod or a copper pipe in the ground. It is there for safety purposes and is only used when there is a short.

Hope this helps.

Cheers,

Gus

[Daniel Bernoulli]

[quote="madjack"]...besides, for less than 3 bucks, you can purchase a sweet little push button, panel mount circuit breaker from www.waytekwire.com ...they are about the size of a matchbook and come in various amp ratings...
madjack [/quote]

MJ,
I located the push button breakers of which you spoke. What panel do you recommend for mounting these? Thanks.
Daniel

[davefullmer]

Daniel,

It looks like to me that the 20 amp (part # 46483) could be mounted in any electrical box. Drill a hole to accept the button and screw the knurled nut on it to hold the breaker to the box. Crimp a push terminals on to the wires and there you have the breaker ready for service. When it trips, push the button from the outside of the box (panel) and power is restored without having to take any covers off the box.

Dave

[Alphacarina]

One important function of the ground rod is to conduct the neural wire back to ground (earth) so that the electrons can flow back and forth to the power company. Here in the USA we use the earth as a conductor. I don't think this is the case everyplace in the world, but it is here in the USA

Nope - You get electrons 'back and forth to the electric company' on the two wires they run to your house and the 'ground' (earth connection) has nothing to do with it

The power company does run their neutral wire highest on their poles and then they 'ground' it at nearly every pole, but this is for lightening protection and the 'earth connection' has nothing to do with moving any electrons . . . . your home power system will still work perfectly with no earth connection - It just won't be very safe

Don