Nissan finally gets it with new 240V portable EVSE

[MikeD]

wwhitney: The following manufacturer's data sheet lists allowable ampacities for NM-B 8/2 and NM-B 8/3 as 40a, not 50a, together with the statement "Type NM-B ampacity limitation shall be in accordance with the 60ºC conductor temperature rating, as specified in the NEC":

https://www.encorewire.com/wp-content/u ... re-NMB.pdf

Am I misunderstanding something? Thanks for all your valuable and informative posts here over the years, btw!

[wwhitney]

No, you're not missing anything, did something earlier in the thread give you a different impression?

NM cable cable is limited to the 60C ampacity for historical/political/robustness issues. Other wiring methods can typically use the 75C ampacity if used with 75C rated terminations. For #8 copper, the 60C ampacity is 40A, and the 75C ampacity is 50A.

Cheers, Wayne

[MikeD]

wwhitney: Yes, your insistence that "The only part of a (properly installed) 40 amp circuit that isn't rated for 40 amps continuous is the circuit breaker itself.".

I did not want readers of this thread to get the mistaken impression that that the NEC currently supports your position that the very commonly used NM-B 8/x cable was "rated 40 amps continuous" when it is appears evident (from NEC article 334.80 "Nonmetallic-Sheathed Cable Types NM, NMC, and NMS/Ampacity" etc) that it does not.

Now, the reason for this (as is the case for many rules in the NEC) is not clear, certainly not to me. I usually assume that it is due to discovery from experimental data and/or experience data over time that there there is a substantial risk of fire and/or shock hazard to rule otherwise.

[wwhitney]

I did not want readers of this thread to get the mistaken impression that that the NEC currently supports your position that the very commonly used NM-B 8/x cable was "rated 40 amps continuous" when it is appears evident (from NEC article 334.80 "Nonmetallic-Sheathed Cable Types NM, NMC, and NMS/Ampacity" etc) that it does not.

Ah, you're still missing the point. When a conductor has a 40 amp rating, that is a continuous rating. Again, it is only the circuit breaker whose rating is not continuous, and that is the reason everything gets upsized by a factor of 125%.

Cheers, Wayne

[goldbrick]

wwhitney: Thanks for all your valuable and informative posts here over the years, btw!

+1

[MikeD]

wwhitney: Yes, I forgot that the basic NEC definition of ampacity involves maximum CONTINUOUS current not just maximum current (more specifically "Ampacity: The current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature rating."), so thank you for being patient in reminding me of that.

I read an explanation of some of the reasoning behind Article 210.10 (A)(1) (...the minimum branch-circuit conductor size...shall have an allowable ampacity not less than ...125 percent of the continuous load...), which readers of this thread might be interested as well, although I am not certain that it applies with a circuit load connected via a receptacle.

Briefly, "The manufacturer [of a connected electrical device] ... [may] count on a relatively cool conductor to function as a heat sink for heat generated within the device under these continuous operating conditions.".

This is a subtlety that I, for one, rarely think about. However, I am all for better understanding of reasons behind important safety rules.

[xhaltsalute]

I'm hoping some of the uber-knowledgeable people on this board can help me out with some advice/opinions. I recently purchased a 2018 Leaf SL which came with the portable 240v EVSE (along with the adapter to plug in to a regular 110v outlet). I am planning on having an "RV plug" (NEMA14-50) installed by a licensed electrician so that I can achieve Level 2 charging at home. I do not have a garage and my car is parked in my driveway. I am planning on having the plug mounted on one of the support posts of my side porch. My main question is: can the EVSE that came with the car safely be used outdoors? (I would also be installing the bracket that came with the EVSE which presumably supports it sufficiently).

Any help is much appreciated. Thanks!

[SageBrush]

I'm hoping some of the uber-knowledgeable people on this board can help me out with some advice/opinions. I recently purchased a 2018 Leaf SL which came with the portable 240v EVSE (along with the adapter to plug in to a regular 110v outlet). I am planning on having an "RV plug" (NEMA14-50) installed by a licensed electrician so that I can achieve Level 2 charging at home. I do not have a garage and my car is parked in my driveway. I am planning on having the plug mounted on one of the support posts of my side porch. My main question is: can the EVSE that came with the car safely be used outdoors? (I would also be installing the bracket that came with the EVSE which presumably supports it sufficiently).

Any help is much appreciated. Thanks!

Go check out an RV park for examples of outdoor plugs and the things people do with them without dying.
That said, do yourself a favor and buy a socket rated for outdoor use and think about a hood to keep it dry.

Better safe than sorry.

[wwhitney]

I don't have an answer to the question on the rating of the Nissan EVSE, but it is worth noting that a Tentative Interim Amendment was issued for the 2017 NEC that would require a GFCI breaker and an in-use weatherproof cover for the receptacle in your application. Even if your jurisdiction hasn't adopted the TIA, it would still be best practice.

Cheers, Wayne

[alozzy]

A cheap enclosure idea for a portable EVSE, like the stock one:

http://www.mynissanleaf.com/viewtopic.p ... 40#p511953