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-   -   Is grounding obsolete? (http://www.diychatroom.com/f18/grounding-obsolete-33647/)

Wildie 12-12-2008 04:28 PM

Is grounding obsolete?
 
GFCI receptacles are now allowed in some area's for replacement of old parallel blade receptacles. As these are usually fed by ungrounded cable.

If GFCI recepts. were to be made manditory for all outlets, then grounded cable would be unnecessary.

Is this possible in the future?

InPhase277 12-12-2008 04:32 PM

Quote:

Originally Posted by Wildie (Post 197233)
GFCI receptacles are now allowed in some area's for replacement of old parallel blade receptacles. As these are usually fed by ungrounded cable.

If GFCI recepts. were to be made manditory for all outlets, then grounded cable would be unnecessary.

Is this possible in the future?

No, because grounding serves more than one purpose. One purpose is to prevent shocks, but other reasons include signal grounding and equipment protection.

And besides, if the GFCI fails in the closed position, then a ground would certainly be helpful. No, there is just no substitute for a real ground. GFCIs are a last ditch effort to keep people safe.

junkcollector 12-12-2008 04:56 PM

Quote:

Originally Posted by InPhase277 (Post 197234)
No, there is just no substitute for a real ground. GFCIs are a last ditch effort to keep people safe.

I agree:thumbsup:

Honestly, the old nongrounding receptacles are fine for 90% of the house. Practically every lamp, TV, and appliance has only a 2 wire cord anyway.


I personally feel much safer with proper grounding than betting my life on a GFCI tripping.

InPhase277 12-12-2008 05:02 PM

Well, I suppose that if someday we only use non-conductive plastics to make our machines with, and no exposed metal parts, and our equipment doesn't require a ground for some kind of signal reference, then maybe all we would need is a 2-wire circuit. Seems to me though that metal will always have some use in our machines, at least for the foreseeable future, so grounding is essential.

KE2KB 12-12-2008 05:33 PM

I can't imaging an all-plastic washing machine. Dryer? Forget it.
3-wire systems are here to stay. I don't even like the fact that most power tools have only 2 wire. I guess I'm an old fashioned fart. I prefer the safety of the 3rd wire.

I suppose that in Europe, where I understand they use a 220V system which is not referenced to Earth (through a CT on the transformer), no 3rd wire is necessry, since no current would ever flow to Earth in such a system.

chris75 12-12-2008 05:38 PM

Quote:

Originally Posted by Wildie (Post 197233)
GFCI receptacles are now allowed in some area's for replacement of old parallel blade receptacles. As these are usually fed by ungrounded cable.

If GFCI recepts. were to be made manditory for all outlets, then grounded cable would be unnecessary.

Is this possible in the future?


No, if you look at 250.114, These cord and plug items require a grounding conductor, and a GFCI cannot be used in lieu of that.


250.114 Equipment Connected by Cord and Plug
Under any of the conditions described in 250.114(1) through (4), exposed non–currentcarrying
metal parts of cord-and-plug-connected equipment likely to become energized
shall be grounded.
Exception: Listed tools, listed appliances, and listed equipment covered in 250.114(2)
through (4) shall not be required to be grounded where protected by a system of double
insulation or its equivalent. Double insulated equipment shall be distinctively marked.
The exception to 250.114 recognizes listed double-insulated appliances, motoroperated
hand-held tools, stationary and fixed motor-operated tools, and light industrial
motor-operated tools as not requiring equipment grounding connections.
(1) In hazardous (classified) locations (see Articles 500 through 517)
(2) Where operated at over 150 volts to ground
Exception No. 1: Motors, where guarded, shall not be required to be grounded.
Exception No. 2: Metal frames of electrically heated appliances, exempted by special
permission, shall not be required to be grounded, in which case the frames shall be
permanently and effectively insulated from ground.
(3) In residential occupancies:
a. Refrigerators, freezers, and air conditioners
b. Clothes-washing, clothes-drying, dish-washing machines; kitchen waste
disposers; information technology equipment; sump pumps and electrical
aquarium equipment
c. Hand-held motor-operated tools, stationary and fixed motor-operated tools,
light industrial motor-operated tools
d. Motor-operated appliances of the following types: hedge clippers, lawn
mowers, snow blowers, and wet scrubbers
e. Portable handlamps
(4) In other than residential occupancies:
a. Refrigerators, freezers, and air conditioners
b. Clothes-washing, clothes-drying, dish-washing machines; information
technology equipment; sump pumps and electrical aquarium equipment
c. Hand-held motor-operated tools, stationary and fixed motor-operated tools,
light industrial motor-operated tools
d. Motor-operated appliances of the following types: hedge clippers, lawn
mowers, snow blowers, and wet scrubbers
e. Portable handlamps
f. Cord-and-plug-connected appliances used in damp or wet locations or by
persons standing on the ground or on metal floors or working inside of metal
tanks or boilers
g. Tools likely to be used in wet or conductive locations

Gigs 12-13-2008 04:45 AM

Quote:

I don't even like the fact that most power tools have only 2 wire
http://en.wikipedia.org/wiki/Appliance_classes

There is no reason to worry about your drill being ungrounded because it's Class 2 double insulated.

Pretty much everything these days is Class 1 (grounded), Class 2 (double insulated), or Class 3 (low voltage wall wart transformer).

Class 0 ungrounded is about a hair away from being banned world wide, and really only still exists for very limited things like table lamps.

LanterDan 12-13-2008 11:36 AM

Realize as well that AC line filters, which are common on things like switch mode power supplies and variable frequency drives, intentionally "leak" current to ground. Take away the ground and the filter won't work as well. And I think the future holds a lot more SMPS and VFDs too.

And as InPhase said above, GFCIs can malfunction too. Several years ago I got bit by a tile saw. I later punched the test button on the GFCI it was plugged into. Nothing. Apparently they all say "Test Monthly" for a reason. (Although I do understand that more recently made devices are supposed to be much better in this regard.)

Wildie 12-13-2008 12:17 PM

Everybody is of the opinion that grounding is important at this time.
With GFCI recepts, ground protection is necessary, as a means of tripping the circuit breaker! However, if AFCI breakers were used, then this would negate the necessity of the ground.
Grounding may increase the cost of wiring by as much as 25%, think of the savings to be had in this regard.

Gigs 12-14-2008 01:20 PM

I suspect as GFCI/AFCI is required in more areas, SMPS makers will have to tighten up their ground leakage. It is possible to do active filtering without leaking as much to ground. Also they can use better Class X/Y caps that don't leak as much.


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