Probably a more germaine section of the code would be 240.5 B(1) which deals
with portable cords. The BIG sticking point is of course as Lee pointed out
the NEC deals with "listed" equipment as much as possible. Unfortunately ,
listing often means that the manufacturer has paid tribute to the listing
agency. I know from experience that UL will sell me a license to put their
sticker on the control panels I build but they don't accept any liability
for the quality or workmanship.
I am not suggesting that someone use a too small "stench" cord as Mr Rice so
poeticly calls them, but the code section above calls out a supply cord of a
listed appliance to be permitted to be supplied with a 20 amp cord capacity
on a 50 amp circuit. I expect the logical thought in the section is that
the listing of the appliance (battery charger for example) would require the
necessary overcurrent device as the first component fed in the appliance.
Personally, I use a heavy duty 12 ga SO cord on The Skunk and if I ever get
a PFC 30 I will use at least a 10 ga cord. In all cases the extension cord
should be as short as possible. It makes no sense to spring for a high
power charger and then lose the power in heat and voltage drop in the
extension cord.
respectfully,
John Neiswanger
The Skunk
http://www.austinev.org/evalbum/751
----- Original Message -----
From: "Lee Hart" <
[email protected]>
To: "Electric Vehicle Discussion List" <
[email protected]>
Sent: Sunday, October 14, 2007 6:34 PM
Subject: Re: [EVDL] 220 volt breaker box + outlet combo
> From: Roland Wiench
>> Correct... You should not take a 50 foot length of No. 18 extension
>> cord and put a 15 amp load on it and plug it into a 15 amp receptacle
>> that is wired with No. 12 AWG wire to a 20 amp circuit breaker...
>> The device at the end of this cord may have overload limits built
>> into it... Some taps that are hard wired (not plug in) will have tap
>> fuses either by a hard wire circuit breaker or even a plug in circuit
>> breaker into a feeder.
>
> Good points.
>
> But, one concern is that most EV battery chargers are *not* UL listed,
> because UL hasn't written test standards for them, and battery charger
> manufacturers haven't seen fit to encourage them to do so. This means that
> they often do *not* adhere to UL or NEC guidelines. There is a tendency to
> depend on these loopholes:
>
> - The charger goes in the car, and UL doesn't regulate stuff in cars.
> - The SAE regulates stuff in cars; but they haven't bothered with EVs.
>
> So, typical chargers do not have the safety overload devices to work
> safely if plugged into a receptacle with a higher current rating.
>
> Part of any EV charging receptacle standard would also need to define what
> must be in the *charger* to make it compliant.
>
> --
> "Excellence does not require perfection." -- Henry James
> --
> Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart-at-earthlink.net
>
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