AFCI for exterior receptacles

[Bruce Ramsey]

Client sent me email yesterday. Has an electric lawn mower. Plugged into the front porch receptacle and cut the front yard no problem. Plugged into receptacle on rear of house and the power shut off. Some lights on the inside went out as well.

So he called the builder. Builder explained that he is required to use AFCI breakers on all circuits. He said the home owner could replace the AFCI with a GFCI on his own but it would be against code. Builder claims he has had other homeowners mention the same issue and there is nothing he can do.

Sounds like the electrician put interior lighting and external receptacles on the same circuit and choose to use an AFCI breaker to meet the interior requirements vs. a GFCI for the external requirements. Either way the combined load of the lights and lawnmower are too much for the circuit and it is tripping.

Finally there is a question in all of this...

Which trumps which? AFCI or GFCI if there are conflicting demands like in this silly builders case of putting external and internal demands on a single circuit?

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[Michael Thomas]

GFCI protection is required at the exterior receptacle outlet - how about a combo AFCI/GFCI breaker?

96-3880-8 BC55C CH FIRE-GUARD AFCI With 5ma GFCI 1 Pole 20 Amp [CH CH120AFGF] - KSCDirect: MRO SuperStore

[Bruce Ramsey]

NC adopted the 2008 NEC effective June 1, 2008, statewide. I know of no NEC requirement for AFCI protection of exterior receptacles. So, unless it is some AHJ's wild wet dream, it is not required.

I agree that there is no need for AFCI protection for exterior receptacles. BUT...there are also interior lighting on the same circuit. So which form of protection is required? AFCI or GFCI?

Yeah, I know they should split the load over two circuits and then the problem does not exist.

[Lou Romano]

Most electrical engineers nowadays give exterior outlets there own circuits so if something on the exterior causes problems it doesn't effect anything inside. The electrician on this job may have cut a corner to save a circuit worth of labor and material or added the outlet in after the fact upon the owner/builders request and just tapped an existing circuit! I would look at the plans and see!

[Jim Port]

Because the circuit serves areas where both AFCI (inside) and the exterior where GFI protection is required, both types of protection will need to be installed.

IMO a poor design choice, but no prohibition code-wise. Just another example of low price winning the bid.

[Jim Luttrall]

The combination AFCI/GFCI breaker is not sufficient for an outlet requiring GFCI protection. There are different values on the sensor and the combo breakers GFCI rating is too high to protect people.
They need to use a dedicated circuit, not a bedroom circuit for the exterior outlet. Most around here use one circuit for all exterior and garage outlets. The builder is trying to save the cost of running the wire from the existing garage /front porch outlet. He saved maybe 15 bucks and likely does not have approved GFCI protection on the rear outlet circuit.

It is likely not the combined load that gives the problem, it is the arc signature of the lawn mower (likely brush type motor) that is tripping the AFCI.

[Jerry Peck]

Finally there is a question in all of this...

Which trumps which? AFCI or GFCI if there are conflicting demands like in this silly builders case of putting external and internal demands on a single circuit?

The AFCI protections is not required ... the GFCI protection is required ... so GFCI protection trumps ... sounds to me like the builder 'trumped' something up at the spur of the moment ...

[Jim Port]

Jerry, how can you say the AFCI component is not needed when the Op said the circuit served an area inside the house that needs AFCI protection? One does not override the other. In this case both protections would be needed as I pointed out above.

[Michael Thomas]

The combination AFCI/GFCI breaker is not sufficient for an outlet requiring GFCI protection. There are different values on the sensor and the combo breakers GFCI rating is too high to protect people.

Depends, for example if you check the specs on the breakers in the link I posted they are Class A GFCIs (5mA trip), and intended to protect building occupants, not Class B (30mA) units intended for equipment protection.

[Jim Luttrall]

Depends, for example if you check the specs on the breakers in the link I posted they are Class A GFCIs (5mA trip), and intended to protect building occupants, not Class B (30mA) units intended for equipment protection.

Sorry, did not notice your link.
It appears that would qualify and do the job but that is not the standard equipment I see around here for an AFCI circuit. That would also not solve the nuisance trip problem associated with an arc producing motor.

[Jerry Peck]

Jerry, how can you say the AFCI component is not needed when the Op said the circuit served an area inside the house that needs AFCI protection? One does not override the other. In this case both protections would be needed as I pointed out above.

Good point ... I was addressing the exterior receptacle outlet itself, not the circuit as the exterior receptacle outlet ITSELF REQUIRES GFCI protection ... which means that GFCI protection is required. Period, no ifs, ands, or buts.

The "good point" part is that the interior CIRCUIT needs AFCI protection ... but not at the expense of not providing GFCI protection for the exterior receptacle outlet.

Thus my answer:

The AFCI protections is not required ... the GFCI protection is required ... so GFCI protection trumps ...

Now, with all the above said, how does the builder provide THE REQUIRED GFCI PROTECTION FOR THE EXTERIOR receptacle outlets? NOT having those receptacle outlets is NOT AN OPTION.

The answer lies in installing GFCI protection for the exterior receptacle outlets, it is, after all, REQUIRED. Period. No going back from that.

And, yes, the interior CIRCUIT needs to be AFCI protected, but I thought we were talking about that exterior receptacle outlet.

The solution, then, is to *re-wire something*, either the interior circuit separate from the exterior receptacle, or, the exterior receptacle from the interior circuit - which is one and the same in what needs to be done.

Will the breakers Micheal linked to work for AFCI protection and for GFCI protection? Only in "USED ON LOADCENTER; FIRE-GUARD[T] BRAND; CH MODEL".

Jim, I do see where my first post only touched on one aspect of what what going through my mind, hopefully, this finishes the thought process in the post.

[Bill Kriegh]

Depends, for example if you check the specs on the breakers in the link I posted they are Class A GFCIs (5mA trip), and intended to protect building occupants, not Class B (30mA) units intended for equipment protection.

The AFCIs referenced in the link are the branch circuit type required prior to the 2008 NEC. And they are available in a number of configurations from CH.

The combination type AFCI required by the 2008 NEC is only available from CH with the 30 mA GFCI.

[Jim Robinson]

What are the breaker sizes? The load should not trip the AFCI, unless it is over the breaker rating, in which case it would trip it regardless of the AFCI feature. If the front is 20 amps, and the back is 15, then there is your problem. Either way the back and front receptacle should be GFCI protected, whether it is at the receptacle or in the panel.

[Michael Thomas]

The combination type AFCI required by the 2008 NEC is only available from CH with the 30 mA GFCI.

Good point, I had not thought to check if the 5mA breakers met the "combination type" requirement.

[Jerry Peck]

Good point, I had not thought to check if the 5mA breakers met the "combination type" requirement.

I missed that too.

[ken horak]

GFCI protection is required at the exterior receptacle outlet - how about a combo AFCI/GFCI breaker?

96-3880-8 BC55C CH FIRE-GUARD AFCI With 5ma GFCI 1 Pole 20 Amp [CH CH120AFGF] - KSCDirect: MRO SuperStore

How about just installing a 12 dollar GFCI receptacle at the outdoor location? Simple,effective,code compliant, and cost effective.

[Lou Romano]

How about just installing a 12 dollar GFCI receptacle at the outdoor location? Simple,effective,code compliant, and cost effective.

What good is that if the AFCI breaker in the panel still trips?

[ken horak]

What good is that if the AFCI breaker in the panel still trips?

As like most others in this thread I was addressing the issue of afci / gfci protection.
Rather then spand 60.00 or more for a breaker ( which i haven't researched to see if it qualifies as protection for personnel) spend 12.00 on a gfci receptacle.
The issue of an overloaded circuit when one is trying to draw more current then the breaker will allow is to just do a rewire of the exterior receptacles or turn off the lights when mowing.

[Lou Romano]

Ken, I may be wrong but I don't think the OP was talking about an overloaded circuit. It was my impression that the OP was saying the circuit was tripping because it is an arc fault circuit and the motor of the electric lawn mower with brushes that arc is tripping it. The only real solution is to run a non arc fault circuit to the outlet and protect it with a GFCI. It is bad planning to install an exterior outlet on a circuit shared with outlets and or lighting inside the house.

[ken horak]

Lou-
Read the third paragraph in the original post, the last sentence
"either way the combined load of the lights and the lawnmower are too much for the circuit and it is tripping"

I agree it is not the smartest way to wire it ,but it is allowed

[John Steinke]

It's a common misconception that ALL circuits need to be AFCI protected. Look to the exact code language; there are plenty of situations where neither AFCI or GFCI protection is required.

Still, that was not the reason for this thread. Let's look at the actual situation:

Either the AFCI is acting badly, or there's a problem. Despite my own opposition to the entire movement to mandate AFCI's -that's not the issue here- the devices are developing a track record of avoiding nuisance tripping.

Moving the mower from one AFCI to another seems to remove the mower as the source of the problem. It's very possible that the AFCI was actually working as designed, and that there is a problem with the circuit.

The AFCI has adopted the position that there has NEVER been a documented instance of a listed, properly operating appliance tripping a properly installed AFCI on a good circuit. Here is your chance to be the first .....

[Vernon Sanders]

A GFCI outlet should have been installed per NEC at exterior outlet. Nothing in code says it can't be tied into lighting circuit, but, a seperate circuit or a receptacle circuit should have been used.

[ken horak]

JOhn
I read the original post as the circuit became overloade with the interior lights on , the mower, and what ever else was operating on that circuit.
I did not read it as an AFCI problem.

[Vernon Sanders]

The lighting circuit was probably overloaded as soon as the mower was turned on, showing that with interior lighting and the mower turned on that the circuit breaker was doing its job. The NEC states that the system will be essentially safe and not necessarily efficient in Article 90 under purpose at the beginning of the code.

[Vernon Sanders]

Remember also that a lighting circuit is only a 15 amp circuit, and that a 20 amp receptacle circuit could have been installed but was not required for exterior outlets.

[Jerry Peck]

This was the ORIGINAL question:

Finally there is a question in all of this...

Which trumps which? AFCI or GFCI if there are conflicting demands like in this silly builders case of putting external and internal demands on a single circuit?

Bruce can tell us if we have answered it yet or not ...

[ken horak]

AFCI or GFCI which trumps which ?

simple neither trumps either

[Vernon Sanders]

In a exterior location receptacle GFCI trumps AFCI. My guess is the only reason that the receptacle was AFCI was that it was tied into a lighting circuit with AFCI breaker. GFCI's are specifically spelled out in the NEC for exterior receptacles with a few exceptions, and this location probably doesn't qualify for these exceptions. Also depending on year of construction a GFCI may not even be required.

[Jerry Peck]

Also depending on year of construction a GFCI may not even be required.

If a GFCI was not required for an exterior receptacle outlet ... no AFCI protection was required either.

[Bruce Ramsey]

Also depending on year of construction a GFCI may not even be required.

new construction closed last month

[Wayne Carlisle]

Tell them to buy a friggin gas powered lawn mower and forget about it!