What is Safer: Old Wiring With AFCI/GFCI Protection or New Wiring With Standard Breakers

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molo

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This is an informal survey: What is a safer situation (less likely to cause a fire):
1.Old damaged (mouse chewed wiring) with AFCI/GFCI breakers
or
2. New Wiring With Standard Breakers
 
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WorthFlorida

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New wiring with afci/gfci. These are not breakers for shorts. They protect from arcs or a ground fault. New breakers have AFCI builtin as one unit. The latest NEC code requires nearly the entire home must be AFCI and GFCI. It is the safest way.
 

molo

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New wiring with afci/gfci. These are not breakers for shorts. They protect from arcs or a ground fault. New breakers have AFCI builtin as one unit. The latest NEC code requires nearly the entire home must be AFCI and GFCI. It is the safest way.

Thank you for the reply. If you had to choose one of the choices in the original post which would you consider safer (less risk of fire)?
 

jadnashua

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If your wires are damaged, and you were to install AFCI and GFCI protection, you may not get the circuit to turn on!

GFCI protects people. AFCI protects property, and indirectly, people. Having them in combination is the safest solution.
 

Reach4

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I would tend to think #1, unless the new wiring was in EMT. Will new wire turn into mouse chewed wiring with time?
 

WorthFlorida

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When any of us are ask this type of question it’s dangerous to answer. Anything damaged must be replaced and to say one is safer than another is a liability factor that only the latest code requirements is the correct answer. The latest code does not need to be implemented with a repair. In this post it is not known what the condition is for the rest of the wiring. Sometimes people ask questions trying to save a dollar or a hassle which usually not the correct way. At times some will ask the same question 10 different ways trying to get an answer that they want to hear.
Just my thoughts. As I have said many times, poor plumbing you get water on your head, poor electric work you get fire and death while standing in water from a leak.
 

molo

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For those who chose the option of new wiring and standard breakers, is that because AFCI and GFCI are not reliable for mouse/squirrel chewed wiring? Are AFCI/GFCI not reliable?
 

wwhitney

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I'm not particularly familiar with the hazards of mouse/squirrel chewed wiring, so my comments are general.

For the hazard of shock, new wiring is useful because it ensures an intact EGC (ground). GFCI is useful because if you are getting shocked hot to ground (rather than neutral), it will detect that and interrupt the circuit. AFCI is not particularly useful, other than to the extent it incorporates GFCI-type technology.

For the hazard of fire, the concern is heating due to a poor connection with a high resistance. New wiring is useful because it will eliminate the damaged sections that may have high resistance or faults. GFCI is maybe useful, as it would detect any hot-ground faults that could cause current flow and heating, but not hot-neutral faults. AFCI is maybe useful--it claims to detect certain types of arcing faults, but I'm not aware of anyone having gathered real world data to show a reduction in fires. And manufacturers grossly exaggerated AFCI's capabilities when they were first required by the NEC, so I am rather skeptical of anything they have to say on the topic.

So I see new wiring as the best/most important mitigation method. GFCI is a simple proven technology that is partially helpful. AFCI is a complex, as yet unproven technology that may be helpful.

Cheers, Wayne

P.S. It is possible my information is out of date, perhaps data has come out in the last 5 or 10 years showing that deployment of AFCIs has in fact led to a reduction in fires. Even if that is the case (I would be interested in a reference), it is at best a second line of defense, the first line being properly installed, undamaged wiring.
 

WorthFlorida

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GFCI's are extremely reliable. They are now microchip controlled and if the chip blows the breaker will trip and not be able to reset. If the power is reversed they will not be able to be reset. If power-in is inadvertently placed on the load side, they will not reset. They are pretty foolproof.

From Leviton GFCI instructions:
• If you miswired the GFCI it may not prevent personal injury or death due to a ground fault (electrical shock).
If you mistakenly connect the LINE wires to the LOAD terminals, the GFCI will not reset and will not provide power to either the GFCI receptacle face or any receptacles fed from the GFCI.
Procedure:
(a) This GFCI is shipped from the factory in the tripped condition and cannot be reset until it is wired correctly and power is supplied to the device. Plug a lamp or radio into the GFCI (and leave it plugged in). Turn the power ON at the service panel. Ensure that the GFCI is still in the tripped condition by pressing the TEST button. If the indicator light on the GFCI receptacle face is ON and the lamp or radio is OFF go to the Troubleshooting section because LINE and LOAD wiring connections have been reversed. You will not be able to RESET the GFCI in this condition.

AFCI most are built into the circuit breakers and the first generation of these about 20 years ago would false trip even with a vacuum clean plugged in. Now as things always improve, they are far more reliable.

https://terrylove.com/forums/index.php?threads/how-does-gfci-go-bad.81779/
Check out these pictures; https://flic.kr/s/aHsmDLAami
 

jadnashua

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As I said earlier, GFCI helps protect people from being shocked...AFCI help people by detecting a flakey connection that is arcing and could cause a fire. The combination is probably your best bet, and is why they are now required on new and remodel work. The definition of new and remodel can vary a bit, so some situations may end up being grandfathered.

Modern GFCI are pretty reliable. AFCI have been around for awhile, but not as long. I personally don't have any experience with them so can't comment on how well or reliably they work. People used to complain about GFCI devices tripping, and people coming home to their freezer melted and the contents lost. If that happens with a newer device, consider it a saving grace, since it could have otherwise killed someone. Enough of a leak to cause a GFCI to trip may not prevent the appliance from appearing to work properly.
 

wwhitney

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As I said earlier, GFCI helps protect people from being shocked...AFCI help people by detecting a flakey connection that is arcing and could cause a fire. The combination is probably your best bet, and is why they are now required on new and remodel work.
To clarify, the phrase "combination AFCI" does not refer to a GFCI/AFCI device. Instead it refers to the 2nd generation of AFCIs which supposedly detect both series and parallel arcs. The 1st generation only attempted to detect parallel arcs.

A GFCI/AFCI device is often called "dual function" by the manufacturer. And several brands of AFCI include some GF capability already, just not necessarily at the ~5ma trip threshold that is required for GFCI. Originally they all did, but a couple brands have eliminated the the GF capability, thereby allowing the use of two single pole AFCIs for a MWBC.

Cheers, Wayne
 
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