The NEC has changed through the years regarding GFCI protection.
120vac outdoor outlets were required to be GFCI protected since ~1972.
In the '80s when I worked as an electrician, outdoor 240 volt NEMA 14-50
outlets were not required to be GFCI protected, but when used to power a
hot tub, or near a pool, they were required to be GFCI protected.
However, the newest NEC regulations require, as I understand it, all
outdoor outlets up to 50 amps be GFCI protected. (I suppose you could
put in a 60 amp breaker to get around the regulation...)
You should not even mention that an EV might use this outlet. It is
simply an outdoor NEMA 14-50 outlet. Perhaps for a welder, or ???
The NEC has become more strict in the past 40 years. :-)
Depending on the brand of panel, 50amp 240V two-pole GFCI breakers are
not insanely expensive. Typically $100 to $150. (For a Scheneider brand,
they can cost over $400, however.) Choose your brand of sub-panel panel
based on your breaker cost. :-) I would put the GFCI breaker so that is
is handy to the outlet so you can easily reset it. At 5 mA trip
threshold, you are likely to have to reset it with regularity. :-)
>>>> GFCI rant <<<
In the USA, the GFCI is set at an insanely low trip threshold of 5 mA.
This is a bit of overreach by the NEC folks. It was initially set far to
conservatively and they can't go up now that they have set the standard
at 5 mA.
In NZ, and other parts of the civilized world, the ground fault (or
residual current) trip threshold is 30 mA. For context, it takes about
100 mA, directly across the chest of a healthy adult to cause a fatal
shock. Small children and adults with unhealthy hearts, have a lower
threshold than 100 mA. Thus, in hospitals, daycare facilities, etc. they
set the requirement at 10 mA for devices with in their reach.
The base voltage in NZ, and most of the world, is 230V. This actually
doubles the chance of getting the critical 100 mA jolt across the chest,
but 30 mA is is still a safer option. First, the threshold is 1/3 of
what is considered the lowest fatal shock current. Next, a shock
directly across the chest is quite rare. You have to touch something of
opposite electrical potential with each hand or arm. This is a _very_
rare occurrence.
The consequence of 5 mA threshold is nuisance tripping. Indeed, less
trip current is "more safe" than more, I suppose, but it is impractical
to apply GFCI to more that select parts of the house (and to the
business.) In contrast the ENTIRE house is protected by GFCI in NZ under
the modern NZ electrical code. Your electric range is GFCI protected, as
are all your appliances, and every light fixture. Every outlet in the
entire house is GFCI protected. You have one GFCI 30 mA breaker to cover
the entire house, and it rarely trips. If the trip was 5 mA, this would
be completely impractical as the nuisance tripping would make normal
activities impossible. A hair dryer could easily darken your entire house.
I should note that commercial settings also have (with some exceptions)
this facility-wide 30 mA GFCI protection on everything, under the modern
electrical code.
Bill D.
On 3/11/2024 10:55 AM, Mark Hanson via EV wrote:
Hi Folks
I was reading in Solar Power World where a California solar installer adds a
14/50 240Vac 50A outlet on the same solar array 50a circuit (for EV charging).
We have added 120vac courtesy outlets on our solar array and pass inspection
even though NEC says solar must be on a dedicated circuit (also tap off garage
circuits that are not dedicated). I couldn’t find anything direct on Google if
it’s a code violation to add a 240V outlet like we do a 120V outlet on the same
50A branch circuit? Does anyone know if this is ok/code compliant?
I assume a local 50A breaker to the 14/50 outlet might be needed since there’s
two sources, 40A solar plus 50A from panel branch circuit.
Best regards Mark
Sent from my iPhone
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