Thanks for bringing this up David! This is a very important topic that I
hope everyone pays attention too. If people are charging their EV's at a
higher rate than they should be, it could create a problem with breakers
getting tripped. While this is not damaging, it may become bothersome to the
provider of the circuit and get them to start questioning the charging of
EV's at their location. It could also be a problem if someone trips a
breaker that they can't get access to so it can be reset - then that circuit
would not be available for the next person to use. 


In more extreme cases, but highly likely, someone drawing more amps than
they should can create a more serious safety issue. Drawing more amps than
the 80% that David points out could result in melted wiring, or worse a
fire. The last thing any of us, the club or EV's in general need is a news
story on how a charging EV caused a fire and property damage. Many of these
circuits and wires are old, with potentially weaker connections and higher


Please heed David's warning. Always check to see what type of power is
available on the circuit, not just by looking at the outlet type but asking
what type of breaker it is and if anything else is sharing the connection,
and set your charger to use NO MORE than 80% of that circuit. It is tempting
to want to charge at a higher rate to be done sooner, but please, take the
few extra moments and keep everyone safe and EV's out the news (at least for
bad news!).




Shawn Waggoner

Florida EAA



[mailto:[EMAIL PROTECTED] On Behalf Of David, FloridaAME
Sent: Sunday, August 10, 2008 5:55 PM
To: 'FLEAA Mailing List'
Subject: [FLEAA] August Meeting and charging


While the meeting yesterday had no real topic I learned a lot about public
charging in a discussion with Charles.  I think others learned a little
about the implications of the National Electric Code Article 625 which is
about charging EV's and conduction charging sites.  

After the meeting I was thinking about something Andrew said about charging
his EV at various sites and having to change the vehicles charge rate.  Back
to the National Electric Code, if you have a 50 Amp circuit breaker and 50
amp wiring, a 50 amp receptacle, you can only use 80% of it  or 40 Amps.
The missing 20% allows for variations in the circuit breaker manufacturing,
things heating up, and a safety factor so the breaker does not trip.  

The other thing is when a 50 amp receptacle is used, many people expect a 50
amp breaker.  But the 50 amp 14-50P receptacle has become the standard or
the RV industry but actually supplies vary 30, 40 and 50 Amps.   

For no problems ask what amperage is available and use 80% of that.


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