Number of recps on GFCI

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jeff43222

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Minneapolis, Minnesota
I just completed roughing a basement finish yesterday that will have 15 duplex receptacles on a 20A circuit (most will be unused and are only installed because code requires them). I originally planned on having GFCI protection on only two of the receptacles -- the ones that will be in unfinished spaces. But when I talked to the inspector yesterday and got the local interpretation of what they consider "finished," it seems that one of the receptacles almost at the end of the chain will be in an unfinished area that I thought would be finished.

So I was thinking of having all the receptacles GFCI protected from the load side of the first GFCI receptacle. I know I'm OK as far as the code is concerned, but I'm wondering if there is a limit to how many receptacles should be installed on the load side. Mainly, my concern is whether having too many would result in either limited GFCI protection (i.e., not tripping when it should), or nuisance tripping. I don't know if receptacle-style GFCIs are designed to only have so many other receptacles downstream.

Or am I worrying about nothing? :D

Inicidentally, the inspector told me that the exceptions to the GFCI rules in unfinished basements are going to disappear in the 2008 NEC.
 
I asked Leviton tech support a while back and they responded that you could protect up to 9 duplex receptacles on the load side of one of their GFCIs (with a caution that your local AHJ may have their own rules)

Other manufacturers may vary - I've never seen a number published by anyone.
 
jeff43222 said:
my concern is whether having too many would result in either limited GFCI protection (i.e., not tripping when it should), or nuisance tripping.
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The protection will remain, nuisance tripping may be an issue.

Each appliance is likely to have some leakage current each one bring the GFCI closer to the trip range.

Also you have more capacitance coupling between hot and ground for each foot of protected branch circuit.

The best way to go IMO is a GFCI receptacle at each point of use with no load side GFCI connections.

But it is not my money to spend.
 
I had a feeling putting too many receptacles on the load side of a GFCI might not be a great idea.

What about protecting the entire circuit with a GFCI breaker? Or would that not make any difference in terms of leakage current and nuisance tripping?
 
jeff43222 said:
I had a feeling putting too many receptacles on the load side of a GFCI might not be a great idea.

What about protecting the entire circuit with a GFCI breaker? Or would that not make any difference in terms of leakage current and nuisance tripping?
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Would this be greatly different than a GFCI as the first receptacle in the circuit?
 
On the one hand, I can see how it wouldn't be greatly different from a single GFCI receptacle at the head of the stream, but I was wondering if the circuitry in a GFCI breaker might make a difference. Then again, leakage current is leakage current, so I guess it wouldn't matter.

It sounds to me like Bob's suggestion is the way to go. That way, there wouldn't be leakage current accumulating from several devices and adding up to enough to trip the GFCI at the head of the stream.
 
What if? you come in to 1st gfi on line side leave on line side to 2nd gfi in on line side out on line side to reg. recp. and hit last one that requried gfci in on line side. each in one in the unfinished area would be protected
 
I don't see much difference between a GFCI receptacle and a GFI breaker in the panelboard when it comes to leakage current. The big difference is that the breaker in the panelboard actually serves two purposes. One is leakage and the other is just as important and that being overcurrent - i.e. it should trip, in your case, somewhere around 20 amps or so. I don't think GFCI receptacles trip on overcurrent.

I've wired lots of these over the years and the only difference is the cost of the breaker versus the cost of the receptacle. You are not worried (maybe you are??) about overcurrent with the GFCI receptacle, only the leakage current since a normal breaker should trip anyways.

Breaker-receptacle - no difference when it comes to leakage current. Properly installed, 5 milliamps or so will trip either device in my experience.

The thing to realize is that GFCI receptacles are NOT overcurrent breakers but merely leakage detectors so my opinion would be to go for the whole string on the GFCI and depend on the panelboard breaker to do it's job in the event of a fault current.
 
If the first ten or so in the string are in the finished area of the basement, then how about just sticking the gfi in the first one of the unfinished area. Now you have 3 or 4 or so protected on the load side of the gfi receptacle outlet , code is met, and money is saved. Just for the record, if you do do it this way, the one gfi will end up behind some sort of unmovable furniture object or other obstructions. This is just a plain electrical law sort of like Ohms Law. It alway's works out that way. Call it Mikey's axiom.
 
The way I laid it out, one receptacle in the furnace room has a separate homerun in MC, one quad receptacle at the panel has its own homerun, and the remaining 12 are daisy-chained on one homerun in NM. The receptacle that I will have to give GFCI protection to is #10 in the chain. Several of the receptacles are in locations where they will only be used for vacuum cleaners and such, and a few will be used for TVs and other electronics. The HO originally only wanted a few receptacles, but I let them know all the others were required by code.
 
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