Should you convert all house outlets to GFCI?

  • Thread starter Greg Bernhardt
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In summary, replacing all outlets with GFCIs outside of specific circumstances may be a smart move. However, there are cases where you can still get shocked and it won't help at all. It may also be more expensive to switch to GFCIs than to use a standard outlet.
  • #36
trainman2001 said:
It won't cause any problem have GFICs everywhere other than overkill. They're not cheap. But, unlike a electromechanical circuit breaker which are pretty simple and reasonably failsafe, a GFI is an electronic instrument that has its own failure modes. When the GFI won't reset, or trips repeatedly, the problem is often that the GFI itself has failed. Electromechanical breakers fail less frequently. Sometimes, they do fail after a trip, but not as often as a GFI's. Achem's Razor… simple is better.
Hmm... Occam’s razor is really a principle for assessing the validity of statements. Would you rather your family drove old cars with no ABS, seatbelts, power steering/brakes or crumple zones, and a solid steering column that impales the driver during a head-on collision? He didn’t say, ‘simple is better’. He said that plurality should not be posited without necessity.

I would argue that a GFI is a complication but necessary - standard breakers are there to protect the wiring from overload and fire, but offer no direct protection from electrocution. They also offer protection against Earth faults with too high a loop impedance to trip a breaker, but enough power to start a fire.

My current house’s electrics are protected by an RCD/GFI made and fitted c.1990. It still passes function tests.

Ask yourself: Are your objections to GFIs based on ‘we’ve been alright so far without’? Can you apply the same logic to car seatbelts? An appliance should withstand a high DC voltage between its live conductors and Earth before being certified safe, hence should not trip an RCD. If you get nuisance trips, do you blame the RCD, or the appliance? All my fridges and freezers are on them, and have been since I was in short trousers.
 
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  • #37
Guineafowl said:
and have been since I was in short trousers.
It's nice and warm here today. I am "in short trousers". :smile:
 
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  • #38
trainman2001 said:
...unlike a electromechanical circuit breaker which are pretty simple and reasonably failsafe, a GFI is an electronic instrument that has its own failure modes.
I would consider the basic concept of a GFI to be quite simple and straightforward, and its operation to face fewer challenges than an electromechanical circuit breaker of which quite a bit more is demanded in a protective role. Certainly the two technologies have their differences, but what then about GFPE devices? Thinking bigger than the branch circuit level, the advantages of an imbalanced current sensing method can be much more effective at clearing a fault early than relying on thermal or electromagnetic flux effects to trigger the actuation of a protective device. GFPE use is mandated in certain installations.
trainman2001 said:
When the GFI won't reset, or trips repeatedly, the problem is often that the GFI itself has failed. Electromechanical breakers fail less frequently. Sometimes, they do fail after a trip, but not as often as a GFI's.
This is a vast quantity of baloney. By far the most frequent cause of GFI trips is a fault after the device, commonly something like a bad connection in a cord or piece of equipment. This fault might be present due to moisture or damage, which causes the GFI to act as designed. Removing the fault often resolves the problem. GFI devices are made to be regularly tested and this test regimen can include using an exteral device ("plug tester") to simulate an imbalance that exceeds the threshold of the trip unit. It would make no sense to design a device that is prone to fail on trip and then require regular trip testing of the device.

On the other hand a garden variety inverse time circuit breaker can be observed to "weaken," or trip more easily, after repeated overload trips. Sometimes this is a transient condition, where simply waiting for the heat mirage to dissapate from the abused breaker restores normal function. But with repeated events the behavior of a breaker can change, and typically manufacturers recommend factory inspection and re-calibration of a device after it clears a fault that may have been near or at its rated limit, say due to a short or ground fault.
 
  • #39
trainman2001 said:
But, unlike a electromechanical circuit breaker which are pretty simple and reasonably failsafe, a GFI is an electronic instrument that has its own failure modes. When the GFI won't reset, or trips repeatedly, the problem is often that the GFI itself has failed. Electromechanical breakers fail less frequently. Sometimes, they do fail after a trip, but not as often as a GFI's.
krater said:
This is a vast quantity of baloney.
Sounds like some references links about this assertion by @trainman2001 would be helpful... :smile:
 
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  • #40
I'm in UK. Although this house has a lot of 'renovated' electrics, there's still enough 'legacy' stuff to need a full re-wire to bring us to 'modern' code.

But, we've done what we could...
Fuse-boards without integral breakers have ground-fault breakers instead of fuse-holders.
Outlets at risk of mishap have integral breakers.
Extension cable reels for garden have 'breaker plugs', 'Test Before Each Use'.
The canopy-sheltered 'weatherproof' box on patio with outlets for party lights, security cameras' IR 'flood-lamp' and LED 'night-light' strip in cats' 'p-porch' has such a 'breaker plug' on the indoor end...
The house-front 'weatherproof' double-outlet for eg Halloween decor has such a 'breaker plug' on the indoor end...

The ring-main that supplies our land-line's DECT phones' base-station and 'Aid-Call' pendant system does get nuisance trips, usually from a spilled kettle. So, those essentials share a modest, wall-hung UPS, to be sure, to be sure...

And, yes, there's also a 'basic' handset daisy-chained from the master phone socket. Remember, if your house and a few neighbours lose power, you'll probably get cell-phone service. If whole street trips out, there'll be much contention at the mast. But the old land-line may be okay...
 

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