The only thing I have ever worried about this with is water tank heaters, that the appliance will be submerged while in use and I use the GFI, or whatever the safety plug is called on it so that it shuts down at the first sign of a leak.

I know that in theory this ground is an important thing for every plug. In reality there are very few homes out there that are wired for this third leg to actually do anything. It's just dead, it leads to nothing. There are a few homes out there that are the exception to that. This is why I use the safety plug on the water heaters, they kill the power and your not counting on the home system to do it.

A few years back a friend of mine, who is an electrician was selling his house. To pass the home inspection he had to have all grounded outlets in the home, 3 leg instead of just 2. So it took us almost 4 hours but we changed every outlet in the house to the 3 prong style plugs. Didn't mean we changed anything in the wiring, just what the plugs looked like. So if your counting on that 3rd leg as a true ground, your already wrong. For a true ground it has to be one of the safety switches like they use in most bathrooms of public buildings and some residential.

 

First of all it's not a "leg" at all. Legs refer to voltage supply lines. a 110/115/120 circuit only has one leg, the other two are "conductors". 208/220/230/240 circuits have 2 legs, and a 3 phase circuit of any voltage has 3 legs. High voltage single phase circuits may also have a neutral and a ground conductor for a total of 4 conductors respectively. 3 phase circuits generally are neutral free but have a 4th conductor for a ground. The "ground" conductor is exactly that. An earth return to dissipate stray current. They normally are not current carrying, just as you said, however should a short occur this conductor assumes the role of carrying the stray current back to earth ground, whether it be the box busses tied to a ground spike, a surface or areal transformer , or at another power origin point. There are two types of "shorts". Ones that short the appliance internally that don't necessarily send current to casings. These shorts will overload the breaker causing it to trip, though the user may be in no danger of receiving a shock. The other type of short is a short to ground. This situation sends stray current to the framework, casing, etc of whatever electrical device is in question. This is the type of short that the ground conductor is responsible for handling. If the short is severe enough to draw excess current, the breaker may trip. If not, you'll get shocked unless the current has a conductive path away from the device better than you.

GFCI's (ground fault circuit interrupter)......NOT designed for circuit or device protection. They are designed as people protection. A GFCI monitors current traveling from line to neutral. If it senses a current imbalance between it's line an neutral taps...even milliamps...it trips. It does not have an amp rating and therefor is NOT a circuit or device protection component. It's merely a very sensitive gauge that monitors a circuit confirming that all the current that an electrical device uses flows from line to neutral without any loss indicating a short to ground.

As for your electrician friend, he must have lived in a house that was built in the 20's before ground circuits were national code. If he just put grounded plates on a receptacle without a ground circuit, then the home inspector didn't do his follow-up very well, and that's one electrician I wouldn't let close to any home I live in. Talk about opening yourself up for a lawsuit.....

I don't want to argue here, but you have a misled idea of electricity and i don't want to see your advice spell harm or damage to someone looking for advice. So don't take it personal, as it is not intended. People just need to know the right info. ALL homes built today do indeed have a ground system, and you're right, they don't play a role in supplying or returning voltage anywhere in the house.....unless there's a problem, then they play a very key role. Remember, AC is not at all like DC, and the generic term "ground" is not at all similair to the two. A DC ground is in fact technically a "neutral negative", which acts much like the "neutral" conductor in an AC system. But that's as close as they come in similarity. So don't EVER treat an AC ground like a DC ground, or every piece of metallic conduit, lamp fixture, stove surface etc will instantly become current carrying conductors throughout the whole building. Anyway 'nuff said. You folks take it how you want, but that's the truth.

Chris

 

Its just a cheapo I snagged when shopping at walmart, Im convinced to go spend the 7 dollars at my local hardware store for a outdoor model.


Thanks for all this info fellas I have learned alot. My house and the shop are earth grounded.

 

You don't ever have to worry about makin me mad about dissagreeing with me at all. I relate things to the best of my knowledge, but have never laid claims to knowing everything. If I knew everything i would have a site whre i was the only one able to give answers. That's why we have discussions, to compare notes as long as it stays polite it's all good.

I trust every word you have said here, it is apparent that you know what your talkin about. For myself I'm comfortable with how I'm doing things just beause of my experiances with it. However I am glad you jumped in so that everybody can hear all sides of it and make their own decision.

The only way I can think of this plug being a problem with shorting, or that I have ever had a problem with is if the plug or appliance were submerged while plugged in. Other then this their just really isn't any way that I can think of for this to create a problem. If it is submerged odds are pretty good you got bigger problems on yer hands.

Remember I'm not tellin anybody they are wrong here, just gettin a better understanding of it and asking questions for myself.

 

No worries Uncle....glad I came across non-offensive. Written word sometimes misses the intended context. You are right that most of todays electrical gizmos make it awful hard to get shocked because they are "double insulated". On top of having the ground circuit, their construction also alleviates possibility of shock. Things like non conductive cases and frameworks, triggers, etc etc really leave no path to you for electricity to travel upon even if they do experience an electrical failure. But double insulation doesn't work for everything...if not strictly due to construction materials used to make it. If there is ANY metallic component attached to the current carrying device ie the motor, the elements or whatever the case may be, and a short to ground occurs without a ground conductor...POW, you a$$ is gonna pucker a little providing YOU yourself have a good path to ground....and yup, old worn out wet cowboy boots on a wet driveway grounds you to the earth fairly well and don't mix all that hot with a live camper wall with no grounds LOL!

Chris

 

You nailed it.

 

Regardless of whats been said here - that's a good plan. The block heater draws something like 8 amps and in my book, overkill is best. Get a digital one if you have the extra funds - they are easier to program.