Will GFCI work with items without equipment ground

[mikestock]

I know it's probably a dumb question but my wife's hair dryer is old and has no equipment ground. Wanted to be sure she is still protected if it should be dropped into water or otherwise shorted.

[Dutch_12078]

Harvard wrote:

mikestock wrote:
All this brings up another related topic. I know I'm wavering.

My RV is in a storage lot where a, low potential, outlet is supplied for each camper. An AC unit or electric water heater will immediately trip the main.

We, pretty much, only plug up to keep batteries charged. Nobody loads anything of consequence on the inverter or 12 volt system.

Every motorhome owner I talk with seems to have a persistent problem with the GFCI's tripping. The only thing we all have in common is that we all have an inverter. Mine is a 1500 watt Xantrex PSW.

Is there something inherent with motorhomes that could cause this? I know the 15 amp connections an campgrounds are GFCI, but I doubt they are used by motorhomes.

Can you imagine having your whole house protected by one 5 mA GFCI.
Why do we think a single 5mA GFCI is going to cope with an entire RV sub system. Just saying.

5mA is the leakage trip point, not the load trip point. As long as GFCI circuitry is built heavy enough to carry the intended load, it will work. For example, a 50 amp 2-pole GFCI breaker would handle a 50 amp RV at normal loading, yet still trip with a 5mA+ leakage.

[Harvard]

The under lying issue with "unexpected" GFCI tripping from an RV sub system is called "stray capacitance" which allows for stray current leakage. Every foot of wire has some stray capacitance and some loads have RFI capacitors across their AC input circuits. All this "Normal Capacitance" soon adds up to be a 5 mA current leakage.

[time2roll]

mikestock wrote:
All this brings up another related topic. I know I'm wavering.

My RV is in a storage lot where a, low potential, outlet is supplied for each camper. An AC unit or electric water heater will immediately trip the main.

We, pretty much, only plug up to keep batteries charged. Nobody loads anything of consequence on the inverter or 12 volt system.

Every motorhome owner I talk with seems to have a persistent problem with the GFCI's tripping. The only thing we all have in common is that we all have an inverter. Mine is a 1500 watt Xantrex PSW.

Is there something inherent with motorhomes that could cause this? I know the 15 amp connections an campgrounds are GFCI, but I doubt they are used by motorhomes.

You can isolate the circuits and discover the offending issue. Or consider using a portable battery charger instead of the converter with entire RV system connected. A 5 amp rated charger should be plenty.

[Sam_Spade]

Harvard wrote:

Can you imagine having your whole house protected by one 5 mA GFCI.
Why do we think a single 5mA GFCI is going to cope with an entire RV sub system. Just saying.

Because it WILL.

It is common practice to use a single GFI in buildings to feed/protect multiple outlets, even in different rooms, sometimes on different sides of the house.

I absolutely HATE having it wired that way.
It is a royal pain to have to search out the tripped GFI when it is in the other end of the house......or in the garage.

[Harvard]

mikestock wrote:
All this brings up another related topic. I know I'm wavering.

My RV is in a storage lot where a, low potential, outlet is supplied for each camper. An AC unit or electric water heater will immediately trip the main.

We, pretty much, only plug up to keep batteries charged. Nobody loads anything of consequence on the inverter or 12 volt system.

Every motorhome owner I talk with seems to have a persistent problem with the GFCI's tripping. The only thing we all have in common is that we all have an inverter. Mine is a 1500 watt Xantrex PSW.

Is there something inherent with motorhomes that could cause this? I know the 15 amp connections an campgrounds are GFCI, but I doubt they are used by motorhomes.

Can you imagine having your whole house protected by one 5 mA GFCI.
Why do we think a single 5mA GFCI is going to cope with an entire RV sub system. Just saying.

[DrewE]

ktmrfs wrote:

wa8yxm wrote:
Will it work: Perfectly
Does the GFCI care. On some of 'em the safety ground is not even connected.

the ground lug better be connected on a GFCI outlet or it is a code violation. And GFCI outlets sold today detect ground/neutral bonding so they must have a connection to the downstream ground.

If you have a safety ground conductor available, indeed it must be connected properly, both per the electric code and per common sense.

If you have an old electric system which lacks a safety ground, it is permissible by code to install a GFCI and so be able to plug in three prong cords (for grounded devices) without rewiring everything. Such an outlet must be labeled as not having an actual safety ground. Absent the GFCI, only ungrounded (two prong) outlets would be permitted to be installed.

Current GFCIs do detect ground/neutral shorts upstream and trip if they are found. I don't believe any of them require that ground and neutral be bonded downstream, but perhaps I am misinformed on that. It's not a universal requirement at any rate.

[ktmrfs]

wa8yxm wrote:
Will it work: Perfectly
Does the GFCI care. On some of 'em the safety ground is not even connected.

the ground lug better be connected on a GFCI outlet or it is a code violation. And GFCI outlets sold today detect ground/neutral bonding so they must have a connection to the downstream ground.

[ktmrfs]

mikestock wrote:
All this brings up another related topic. I know I'm wavering.

My RV is in a storage lot where a, low potential, outlet is supplied for each camper. An AC unit or electric water heater will immediately trip the main.

We, pretty much, only plug up to keep batteries charged. Nobody loads anything of consequence on the inverter or 12 volt system.

Every motorhome owner I talk with seems to have a persistent problem with the GFCI's tripping. The only thing we all have in common is that we all have an inverter. Mine is a 1500 watt Xantrex PSW.

Is there something inherent with motorhomes that could cause this? I know the 15 amp connections an campgrounds are GFCI, but I doubt they are used by motorhomes.

if the trailer/motorhome has an outside outlet (which virtually all do) in wet weather moisture can build up in that outlet and cause enough leakage current to trip an upstream GFCI outlet. be it the breaker with GFCI or the trailer GFCI.

[Hurricaner]

mikestock wrote:
All this brings up another related topic. I know I'm wavering.

My RV is in a storage lot where a, low potential, outlet is supplied for each camper. An AC unit or electric water heater will immediately trip the main.

We, pretty much, only plug up to keep batteries charged. Nobody loads anything of consequence on the inverter or 12 volt system.

Every motorhome owner I talk with seems to have a persistent problem with the GFCI's tripping. The only thing we all have in common is that we all have an inverter. Mine is a 1500 watt Xantrex PSW.

Is there something inherent with motorhomes that could cause this? I know the 15 amp connections an campgrounds are GFCI, but I doubt they are used by motorhomes.

Read ktmrfs post above (very good post) and note the last paragraph. If the inverter has the neutral/ ground bonded and its transfer switch defaults to the inverter, before the switch can transfer the gfi will pick up a neutral to ground fault and trips. This use to be a problem years ago but I thought the inverter manufactures had solved it, but maybe not. It could also be the inverters were not installed properly.

Sam

[Sam_Spade]

Terryallan wrote:
In truth. The GFCI is NOT there to protect YOU. It is there to protect the circuits. That by doing it's job, it also protects you, is just a bonus

Absolutely wrong.
Most of the devices don't care where the current goes OUTSIDE the working parts of the device.
Human beings certainly care though.
GFCI is a safety device. Circuit breakers are equipment protection.

[mikestock]

All this brings up another related topic. I know I'm wavering.

My RV is in a storage lot where a, low potential, outlet is supplied for each camper. An AC unit or electric water heater will immediately trip the main.

We, pretty much, only plug up to keep batteries charged. Nobody loads anything of consequence on the inverter or 12 volt system.

Every motorhome owner I talk with seems to have a persistent problem with the GFCI's tripping. The only thing we all have in common is that we all have an inverter. Mine is a 1500 watt Xantrex PSW.

Is there something inherent with motorhomes that could cause this? I know the 15 amp connections an campgrounds are GFCI, but I doubt they are used by motorhomes.

[wa8yxm]

Will it work: Perfectly
Does the GFCI care. On some of 'em the safety ground is not even connected.

[JRscooby]

Terryallan wrote:
In truth. The GFCI is NOT there to protect YOU. It is there to protect the circuits. That by doing it's job, it also protects you, is just a bonus

False. The only reason to have a GFI is to protect people. But still not good to depend on them

[ktmrfs]

while a GFCI is designed to protect you in the case of getting across hot and neutral it is NOT guaranteed to protect you. If you are well insulated from any ground path (in the house with rubber soled insulated shoes) and get across the hot and neutral ALL the current flows through you via the hot and neutral and none through any ground path. hence no GFCI trip.

Of course this is not the typical fault case but it can exist. As an example try using a outlet tester with a GFCI test button in a typical trailer hooked to a typical generator with unbonded ground and neutral. in most cases it will NOT trip any GFCI outlets. The reason is that the neutral and ground in the trailer are not bonded, nor are they bonded at the generator, and the trailer sits on rubber tires generator sits outside with plastic high insulation resistance between the neutral or ground and earth grounde hence limited or no ground path. same as if you got across hot and neutral in the trailer.

A outlet based GFCI provide NO overcurrent protection just current imbalance protection. It relies on an upstream CB for overecurrent protection, a Circuit breaker GFCI will provide overcurrent protection and current imbalance protection.

Now a GFCI will also detect and trip on one other fault. A downstream ground/neutral bond. By code ground and neutral are not to be connected together anywhere but the main breaker panel. so if ground and neutral are bonded downstream of the GFCI it will detect this short and will trip. This will occur even if there is no current flowing in the circuit.

[opnspaces]

time2roll wrote:

Sam Spade wrote:
If the bowl of water it was dropped into is not grounded, then the detector likely wouldn't trip until a persons hand supplied a foreign ground....and maybe not then.

I am trying to figure out how you drop a hot GFCI outlet into a bowl of water and not touch the ground pin of the connector.

However if 5ma leaves the bowl the GFCI will trip.

You're not dropping the outlet into the water. You are dropping the two prong corded hair dryer into the bowl of water.