GFCI vs. Arc Fault

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  #1  
Old 06-21-05, 09:10 AM
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GFCI vs. Arc Fault

What is the difference between GFCI and Arc Fault circuit breakers, or actually do Arc Fault breakers also act as GFCI? I went to buy a GFCI at Lowe's for my Square D load center. It was ~$32, but turned out to be for the Homeline series, and I need QO series. The 20 amp breaker for QO is ~$54. They have Arc Fault breakers for much less. Will they accomplish the same purpose as GFCI or do I have to suck it up and spend the $54?

Thanks, James
 
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  #2  
Old 06-21-05, 09:23 AM
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AFCI breakers protect against arc faults. GFCI breakers protect against ground faults. They are different kinds of faults.

Most AFCI breakers do have at least some GFCI capability. Some have only 30mA GFCI protection, and others have 5mA protection. If you need to meet GFCI code requirements (e.g., for a bathroom or kitchen), you need 5mA protection.

But most people don't buy GFCI breakers at all these days, except for things like hot tubs. A GFCI receptacle, installed at the first outlet on a circuit, provides the same protection for a lot less money.
 
  #3  
Old 06-21-05, 09:27 AM
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GFCI and AFCI are quite different.

If you need ground fault protection (ie, bathroom, kitchen, outdoors, unfinished basement, garage, etc), you either use a GFCI breaker, or, MUCH cheaper, a GFCI receptical. An Arc Fault breaker will NOT provide this protection.

What is your application where you need ground fault protection?
 
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Old 06-21-05, 09:51 AM
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The circuit covers a bathroom outlet, bathroom lighting, and 4 outdoor outlets.

Are you saying that I would only need one GFCI receptacle to cover the whole circuit? What if there are multiple runs on the same circuit?

If I can use a GFCI receptacle and it has to be at the first outlet on the circuit, how would I determine which is the first outlet?

Thanks,

James
 
  #5  
Old 06-21-05, 09:54 AM
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Is this a new circuit, or an existing circuit? Did it have GFCI protection before? What happened to that? Why are you doing anything at all?

In most cases, one GFCI receptacle can cover the whole circuit. But it's possible that you might have unusual cable routing that would require more than one. Even so, multiple GFCI receptacles is often cheaper than one GFCI breaker.

In what year was this house built?
 
  #6  
Old 06-21-05, 10:35 AM
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Originally Posted by John Nelson
Is this a new circuit, or an existing circuit? Did it have GFCI protection before? What happened to that? Why are you doing anything at all?

In most cases, one GFCI receptacle can cover the whole circuit. But it's possible that you might have unusual cable routing that would require more than one. Even so, multiple GFCI receptacles is often cheaper than one GFCI breaker.

In what year was this house built?
Existing circuit. Had a GFCI circuit breaker that failed and was replaced with a standard breaker. Last week one of the outlets on the ciruict failed (open neutral) and I'm trying to get the circuit back to meeting code, being safe, and hopefully preventing the problem from reoccurring. What makes me think the circuit has multiple runs is, there are two receptacles on the circuit that are at the ends of a run (wires coming in, but not going out of the junction box) on opposite sides of the house.

House was built in 1979 if I remember correctly. Cheap!

Jas.
 
  #7  
Old 06-22-05, 07:03 AM
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jascooper,

Basically you can use a GFCI to cover what you are saying but as JOHN has said it would need to be the FIRST recept in the chain of items you are planning to cover.

To find the FIRST one in the chain you usually have to do a process of elimination but for the most part you find the closest recept to the circuit in question nearest to the panel and start their.....You will know quicking as you disconnect them if the other items on the circuit no longer work....

As a side note for NEW installations of GFCI circuits....you are not allowed to run the GFCI in the bathroom with the outside recepts and basement recepts and so on.......they have to be different circuits not to mention alot of other issues when dealing with bathrooms...but one key thing many overlook is the bathroom has to be GFCI 20A and the outside recepts and basements can be 15A or 20A.....many thing all the GFCI's need to be 20A but not the case......Just wanted to throw that at ya...but in your case it is all existing..so not possible for ya unless major reworking....

So basically I would put a GFCI in the bathroom recept and you JUST may get lucky and it cover the outside recepts....as to be honest with you chances are they hit the indoor ones first before doing the outdoor ones...so you never know...you may luck out with that recept being first in the chain...
 
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Old 06-22-05, 08:44 AM
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Unless you relish the challenge and money is very tight, I'd just spring for the $54 and get it over with. On the other hand, if time is more available than money, you can do some investigation and see how few GFCIs you can get away with. I'd probably start by going to the outlet physically closest to the panel, one that has more than one cable in the box. Shut off the breaker, pull out the receptacle, disconnect all the wires (after recording how they were connected!), and turn the breaker back on. Whatever is now dead will be protected by a GFCI at that location. So shut off the breaker again, and install the GFCI receptacle there (after figuring out which is line and which is load). Repeat this process until all the outlets requiring GFCI protection are protected. It'll be more work, but it'll almost certainly be cheaper than $54, and you'll learn something in the process.

If time is much more plentiful than money, you can disconnect the receptacles one at a time, and make a complete list of what is downstream from what before installing any GFCIs. In that way, you can determine exactly what is the absolute fewest GFCI receptacles you can get away with, and where they should go. Think of it as a science fair project.
 
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Old 06-22-05, 12:06 PM
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Thanks for all the advice. Although I could afford the $54, I hate the fact that the breaker I need is the only one that costs that much. Every other GFCI or AFCI breaker is <$32. I'd also like to get a better idea of what's going on in my house, and I have lots of time to waste, being retired.

Just a couple more questions if I might:

I had replaced the GFCI breaker that I had with a 10 amp standard breaker. Should that be upped to 20amps (standard breaker) or doesn't it make a difference? There is a small air conditioner (6,000 BTU?) on the circuit which probably draws the most power.

The circuit also controls bathroom lighting (3 lights, exahust fan). Is there anything I need to consider here in doing my troubleshooting? (e.g. removing bulbs, disconnecting the switches, etc.)

Thanks again. The folks on this site have already saved me a bunch of money, and solved many problems that otherwise would have required expensive service professionals to solve.

James
 
  #10  
Old 06-22-05, 12:13 PM
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Are you 100% sure that you have a 10-amp breaker? Although such breakers exist, they are extremely rare in most homes. The minimum size typically used is 15 amps, especially in a house built in 1979.

You can almost never safely increase the size of your breaker without creating a serious code violation and substantially increasing the risk of burning your house down.

Part of the reason your breaker is so expensive is that you have the cream of the crop panel. It should be of some comfort to you that you have the best, and then maybe it won't be so painful paying more for the breaker.
 
  #11  
Old 06-22-05, 01:36 PM
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Yeah, I'm sure it's 10 amp. I was the one who put it in, and it's clearly marked on the face of it.

I replace a GFCI breaker that was bad (or at least I thought it was bad) with the 10 amp breaker. I figured it was just a matter of not plugging anything in to a socket while brushing my teeth or standing in water until I could find a replacement GFCI breaker. WRONG!

So now I don't have the original breaker, or know what amperage it was, other than knowing the width of the opening it fit in. All I know now is that the circuit controls 1 bathroom outlet, 5 bathroom light bulbs, 2 inside (dual) outlets and 4 ouside (dual) outlets.

Everything has worked fine for a few years now until I developed this open neutral problem when the air conditioner kicked in. This has happened twice. Neither time did it trip the circuit breaker. The first time, I replaced 3 outlets, and moved the connections from backstab to screw terminals. Doing that didn't solve the problem but the outlets mysteriously started working again a short time later. The second time it happened, I checked connections again, and again after a few hours rest with no load, things mysteriously are working again.

Right now I just want to get where my house is safe, I won't get electrocuted using my bathroom or outside outlets, and hopefully the open neutral problem won't reoccur.

James
 
  #12  
Old 06-22-05, 01:39 PM
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Well, now you're in the unenviable position of not knowing what size breaker belongs there. I would check the gauge of the wire connected to the breaker, and make sure it is copper. I would then open up all the boxes on the circuit to make sure the same gauge wire is there too. If you don't know how to tell the difference between 12-gauge and 14-gauge, then go to your home center and spend a quarter to buy a foot of each for comparison.
 
  #13  
Old 06-22-05, 01:51 PM
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Originally Posted by John Nelson
If you don't know how to tell the difference between 12-gauge and 14-gauge, then go to your home center and spend a quarter to buy a foot of each for comparison.

...And be sure to look at the thinkness of the actual wire, NOT just the insulation, and definately not the entire cable. The cable thickness will deceive you. A piece of 14 guage Romex from the 1970s probably looks as thick if not thicker than a piece of 12 guage Romex you would buy today.

I had to splice some new 12-3 in a j-box with some original 12-3 in my 1975 house. The old stuff looked nearly twice as thick. I assume todays insulation is better, hence thinner.
 
  #14  
Old 06-23-05, 04:05 PM
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Solid copper. I got a piece of 12 and 14 gauge for comparison. Looks like 14 at the circuit breaker. I haven't checked the outlet boxes yet, but have to assume it will be 14 gauge too.
 
  #15  
Old 06-23-05, 08:09 PM
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So then you need a 15-amp breaker.
 
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